/* ===========================================================
 * JFreeChart : a free chart library for the Java(tm) platform
 * ===========================================================
 *
 * (C) Copyright 2000-2013, by Object Refinery Limited and Contributors.
 *
 * Project Info:  http://www.jfree.org/jfreechart/index.html
 *
 * This library is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2.1 of the License, or
 * (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
 * USA.
 *
 * [Oracle and Java are registered trademarks of Oracle and/or its affiliates.
 * Other names may be trademarks of their respective owners.]
 *
 * ---------------------
 * DatasetUtilities.java
 * ---------------------
 * (C) Copyright 2000-2013, by Object Refinery Limited and Contributors.
 *
 * Original Author:  David Gilbert (for Object Refinery Limited);
 * Contributor(s):   Andrzej Porebski (bug fix);
 *                   Jonathan Nash (bug fix);
 *                   Richard Atkinson;
 *                   Andreas Schroeder;
 *                   Rafal Skalny (patch 1925366);
 *                   Jerome David (patch 2131001);
 *                   Peter Kolb (patch 2791407);
 *                   Martin Hoeller (patch 2952086);
 *
 * Changes (from 18-Sep-2001)
 * --------------------------
 * 18-Sep-2001 : Added standard header and fixed DOS encoding problem (DG);
 * 22-Oct-2001 : Renamed DataSource.java --> Dataset.java etc. (DG);
 * 15-Nov-2001 : Moved to package com.jrefinery.data.* in the JCommon class
 *               library (DG);
 *               Changed to handle null values from datasets (DG);
 *               Bug fix (thanks to Andrzej Porebski) - initial value now set
 *               to positive or negative infinity when iterating (DG);
 * 22-Nov-2001 : Datasets with containing no data now return null for min and
 *               max calculations (DG);
 * 13-Dec-2001 : Extended to handle HighLowDataset and IntervalXYDataset (DG);
 * 15-Feb-2002 : Added getMinimumStackedRangeValue() and
 *               getMaximumStackedRangeValue() (DG);
 * 28-Feb-2002 : Renamed Datasets.java --> DatasetUtilities.java (DG);
 * 18-Mar-2002 : Fixed bug in min/max domain calculation for datasets that
 *               implement the CategoryDataset interface AND the XYDataset
 *               interface at the same time.  Thanks to Jonathan Nash for the
 *               fix (DG);
 * 23-Apr-2002 : Added getDomainExtent() and getRangeExtent() methods (DG);
 * 13-Jun-2002 : Modified range measurements to handle
 *               IntervalCategoryDataset (DG);
 * 12-Jul-2002 : Method name change in DomainInfo interface (DG);
 * 30-Jul-2002 : Added pie dataset summation method (DG);
 * 01-Oct-2002 : Added a method for constructing an XYDataset from a Function2D
 *               instance (DG);
 * 24-Oct-2002 : Amendments required following changes to the CategoryDataset
 *               interface (DG);
 * 18-Nov-2002 : Changed CategoryDataset to TableDataset (DG);
 * 04-Mar-2003 : Added isEmpty(XYDataset) method (DG);
 * 05-Mar-2003 : Added a method for creating a CategoryDataset from a
 *               KeyedValues instance (DG);
 * 15-May-2003 : Renamed isEmpty --> isEmptyOrNull (DG);
 * 25-Jun-2003 : Added limitPieDataset methods (RA);
 * 26-Jun-2003 : Modified getDomainExtent() method to accept null datasets (DG);
 * 27-Jul-2003 : Added getStackedRangeExtent(TableXYDataset data) (RA);
 * 18-Aug-2003 : getStackedRangeExtent(TableXYDataset data) now handles null
 *               values (RA);
 * 02-Sep-2003 : Added method to check for null or empty PieDataset (DG);
 * 18-Sep-2003 : Fix for bug 803660 (getMaximumRangeValue for
 *               CategoryDataset) (DG);
 * 20-Oct-2003 : Added getCumulativeRangeExtent() method (DG);
 * 09-Jan-2003 : Added argument checking code to the createCategoryDataset()
 *               method (DG);
 * 23-Mar-2004 : Fixed bug in getMaximumStackedRangeValue() method (DG);
 * 31-Mar-2004 : Exposed the extent iteration algorithms to use one of them and
 *               applied noninstantiation pattern (AS);
 * 11-May-2004 : Renamed getPieDatasetTotal --> calculatePieDatasetTotal (DG);
 * 15-Jul-2004 : Switched getX() with getXValue() and getY() with getYValue();
 * 24-Aug-2004 : Added argument checks to createCategoryDataset() method (DG);
 * 04-Oct-2004 : Renamed ArrayUtils --> ArrayUtilities (DG);
 * 06-Oct-2004 : Renamed findDomainExtent() --> findDomainBounds(),
 *               findRangeExtent() --> findRangeBounds() (DG);
 * 07-Jan-2005 : Renamed findStackedRangeExtent() --> findStackedRangeBounds(),
 *               findCumulativeRangeExtent() --> findCumulativeRangeBounds(),
 *               iterateXYRangeExtent() --> iterateXYRangeBounds(),
 *               removed deprecated methods (DG);
 * 03-Feb-2005 : The findStackedRangeBounds() methods now return null for
 *               empty datasets (DG);
 * 03-Mar-2005 : Moved createNumberArray() and createNumberArray2D() methods
 *               from DatasetUtilities --> DataUtilities (DG);
 * 22-Sep-2005 : Added new findStackedRangeBounds() method that takes base
 *               argument (DG);
 * ------------- JFREECHART 1.0.x ---------------------------------------------
 * 15-Mar-2007 : Added calculateStackTotal() method (DG);
 * 27-Mar-2008 : Fixed bug in findCumulativeRangeBounds() method (DG);
 * 28-Mar-2008 : Fixed sample count in sampleFunction2D() method, renamed
 *               iterateXYRangeBounds() --> iterateRangeBounds(XYDataset), and
 *               fixed a bug in findRangeBounds(XYDataset, false) (DG);
 * 28-Mar-2008 : Applied a variation of patch 1925366 (from Rafal Skalny) for
 *               slightly more efficient iterateRangeBounds() methods (DG);
 * 08-Apr-2008 : Fixed typo in iterateRangeBounds() (DG);
 * 08-Oct-2008 : Applied patch 2131001 by Jerome David, with some modifications
 *               and additions and some new unit tests (DG);
 * 12-Feb-2009 : Added sampleFunction2DToSeries() method (DG);
 * 27-Mar-2009 : Added new methods to find domain and range bounds taking into
 *               account hidden series (DG);
 * 01-Apr-2009 : Handle a StatisticalCategoryDataset in
 *               iterateToFindRangeBounds() (DG);
 * 16-May-2009 : Patch 2791407 - fix iterateToFindRangeBounds for
 *               MultiValueCategoryDataset (PK);
 * 10-Sep-2009 : Fix bug 2849731 for IntervalCategoryDataset (DG);
 * 16-Feb-2010 : Patch 2952086 - find z-bounds (MH);
 *
 */

package org.jfree.data.general;

import java.util.ArrayList;
import java.util.List;

import org.jfree.chart.util.ArrayUtilities;
import org.jfree.chart.util.ParamChecks;
import org.jfree.data.DomainInfo;
import org.jfree.data.DomainOrder;
import org.jfree.data.KeyToGroupMap;
import org.jfree.data.KeyedValues;
import org.jfree.data.Range;
import org.jfree.data.RangeInfo;
import org.jfree.data.category.CategoryDataset;
import org.jfree.data.category.CategoryRangeInfo;
import org.jfree.data.category.DefaultCategoryDataset;
import org.jfree.data.category.IntervalCategoryDataset;
import org.jfree.data.function.Function2D;
import org.jfree.data.statistics.BoxAndWhiskerCategoryDataset;
import org.jfree.data.statistics.BoxAndWhiskerXYDataset;
import org.jfree.data.statistics.MultiValueCategoryDataset;
import org.jfree.data.statistics.StatisticalCategoryDataset;
import org.jfree.data.xy.IntervalXYDataset;
import org.jfree.data.xy.OHLCDataset;
import org.jfree.data.xy.TableXYDataset;
import org.jfree.data.xy.XYDataset;
import org.jfree.data.xy.XYDomainInfo;
import org.jfree.data.xy.XYRangeInfo;
import org.jfree.data.xy.XYSeries;
import org.jfree.data.xy.XYSeriesCollection;
import org.jfree.data.xy.XYZDataset;


/**
 * A collection of useful static methods relating to datasets.
 */
public final class DatasetUtilities {

    /**
     * Private constructor for non-instanceability.
     */
    private DatasetUtilities() {
        // now try to instantiate this ;-)
    }

    /**
     * Calculates the total of all the values in a {@link PieDataset}.  If
     * the dataset contains negative or <code>null</code> values, they are
     * ignored.
     *
     * @param dataset  the dataset (<code>null</code> not permitted).
     *
     * @return The total.
     */
    public static double calculatePieDatasetTotal(PieDataset dataset) {
        ParamChecks.nullNotPermitted(dataset, "dataset");
        List<Comparable> keys = dataset.getKeys();
        double totalValue = 0;
        for (Comparable current : keys) {
            if (current != null) {
                Number value = dataset.getValue(current);
                double v = 0.0;
                if (value != null) {
                    v = value.doubleValue();
                }
                if (v > 0) {
                    totalValue = totalValue + v;
                }
            }
        }
        return totalValue;
    }

    /**
     * Creates a pie dataset from a table dataset by taking all the values
     * for a single row.
     *
     * @param dataset  the dataset (<code>null</code> not permitted).
     * @param rowKey  the row key.
     *
     * @return A pie dataset.
     */
    public static PieDataset createPieDatasetForRow(CategoryDataset dataset,
                                                    Comparable rowKey) {
        int row = dataset.getRowIndex(rowKey);
        return createPieDatasetForRow(dataset, row);
    }

    /**
     * Creates a pie dataset from a table dataset by taking all the values
     * for a single row.
     *
     * @param dataset  the dataset (<code>null</code> not permitted).
     * @param row  the row (zero-based index).
     *
     * @return A pie dataset.
     */
    public static PieDataset createPieDatasetForRow(CategoryDataset dataset,
                                                    int row) {
        DefaultPieDataset result = new DefaultPieDataset();
        int columnCount = dataset.getColumnCount();
        for (int current = 0; current < columnCount; current++) {
            Comparable columnKey = dataset.getColumnKey(current);
            result.setValue(columnKey, dataset.getValue(row, current));
        }
        return result;
    }

    /**
     * Creates a pie dataset from a table dataset by taking all the values
     * for a single column.
     *
     * @param dataset  the dataset (<code>null</code> not permitted).
     * @param columnKey  the column key.
     *
     * @return A pie dataset.
     */
    public static PieDataset createPieDatasetForColumn(CategoryDataset dataset,
                                                       Comparable columnKey) {
        int column = dataset.getColumnIndex(columnKey);
        return createPieDatasetForColumn(dataset, column);
    }

    /**
     * Creates a pie dataset from a {@link CategoryDataset} by taking all the
     * values for a single column.
     *
     * @param dataset  the dataset (<code>null</code> not permitted).
     * @param column  the column (zero-based index).
     *
     * @return A pie dataset.
     */
    public static PieDataset createPieDatasetForColumn(CategoryDataset dataset,
                                                       int column) {
        DefaultPieDataset result = new DefaultPieDataset();
        int rowCount = dataset.getRowCount();
        for (int i = 0; i < rowCount; i++) {
            Comparable rowKey = dataset.getRowKey(i);
            result.setValue(rowKey, dataset.getValue(i, column));
        }
        return result;
    }

    /**
     * Creates a new pie dataset based on the supplied dataset, but modified
     * by aggregating all the low value items (those whose value is lower
     * than the <code>percentThreshold</code>) into a single item with the
     * key "Other".
     *
     * @param source  the source dataset (<code>null</code> not permitted).
     * @param key  a new key for the aggregated items (<code>null</code> not
     *             permitted).
     * @param minimumPercent  the percent threshold.
     *
     * @return The pie dataset with (possibly) aggregated items.
     */
    public static PieDataset createConsolidatedPieDataset(PieDataset source,
            Comparable key, double minimumPercent) {
        return DatasetUtilities.createConsolidatedPieDataset(source, key,
                minimumPercent, 2);
    }

    /**
     * Creates a new pie dataset based on the supplied dataset, but modified
     * by aggregating all the low value items (those whose value is lower
     * than the <code>percentThreshold</code>) into a single item.  The
     * aggregated items are assigned the specified key.  Aggregation only
     * occurs if there are at least <code>minItems</code> items to aggregate.
     *
     * @param source  the source dataset (<code>null</code> not permitted).
     * @param key  the key to represent the aggregated items.
     * @param minimumPercent  the percent threshold (ten percent is 0.10).
     * @param minItems  only aggregate low values if there are at least this
     *                  many.
     *
     * @return The pie dataset with (possibly) aggregated items.
     */
    public static PieDataset createConsolidatedPieDataset(PieDataset source,
            Comparable key, double minimumPercent, int minItems) {

        DefaultPieDataset result = new DefaultPieDataset();
        double total = DatasetUtilities.calculatePieDatasetTotal(source);

        //  Iterate and find all keys below threshold percentThreshold
        List<Comparable> keys = source.getKeys();
        List<Comparable> otherKeys = new ArrayList<Comparable>();
        for (Comparable currentKey : keys) {
            Number dataValue = source.getValue(currentKey);
            if (dataValue != null) {
                double value = dataValue.doubleValue();
                if (value / total < minimumPercent) {
                    otherKeys.add(currentKey);
                }
            }
        }

        //  Create new dataset with keys above threshold percentThreshold
        double otherValue = 0;
        for (Comparable currentKey : keys) {
            Number dataValue = source.getValue(currentKey);
            if (dataValue != null) {
                if (otherKeys.contains(currentKey)
                        && otherKeys.size() >= minItems) {
                    //  Do not add key to dataset
                    otherValue += dataValue.doubleValue();
                } else {
                    //  Add key to dataset
                    result.setValue(currentKey, dataValue);
                }
            }
        }
        //  Add other category if applicable
        if (otherKeys.size() >= minItems) {
            result.setValue(key, otherValue);
        }
        return result;
    }

    /**
     * Creates a {@link CategoryDataset} that contains a copy of the data in an
     * array (instances of <code>Double</code> are created to represent the
     * data items).
     * <p>
     * Row and column keys are created by appending 0, 1, 2, ... to the
     * supplied prefixes.
     *
     * @param rowKeyPrefix  the row key prefix.
     * @param columnKeyPrefix  the column key prefix.
     * @param data  the data.
     *
     * @return The dataset.
     */
    public static CategoryDataset createCategoryDataset(String rowKeyPrefix,
            String columnKeyPrefix, double[][] data) {

        DefaultCategoryDataset result = new DefaultCategoryDataset();
        for (int r = 0; r < data.length; r++) {
            String rowKey = rowKeyPrefix + (r + 1);
            for (int c = 0; c < data[r].length; c++) {
                String columnKey = columnKeyPrefix + (c + 1);
                result.addValue(new Double(data[r][c]), rowKey, columnKey);
            }
        }
        return result;

    }

    /**
     * Creates a {@link CategoryDataset} that contains a copy of the data in
     * an array.
     * <p>
     * Row and column keys are created by appending 0, 1, 2, ... to the
     * supplied prefixes.
     *
     * @param rowKeyPrefix  the row key prefix.
     * @param columnKeyPrefix  the column key prefix.
     * @param data  the data.
     *
     * @return The dataset.
     */
    public static CategoryDataset createCategoryDataset(String rowKeyPrefix,
            String columnKeyPrefix, Number[][] data) {

        DefaultCategoryDataset result = new DefaultCategoryDataset();
        for (int r = 0; r < data.length; r++) {
            String rowKey = rowKeyPrefix + (r + 1);
            for (int c = 0; c < data[r].length; c++) {
                String columnKey = columnKeyPrefix + (c + 1);
                result.addValue(data[r][c], rowKey, columnKey);
            }
        }
        return result;

    }

    /**
     * Creates a {@link CategoryDataset} that contains a copy of the data in
     * an array (instances of <code>Double</code> are created to represent the
     * data items).
     * <p>
     * Row and column keys are taken from the supplied arrays.
     *
     * @param rowKeys  the row keys (<code>null</code> not permitted).
     * @param columnKeys  the column keys (<code>null</code> not permitted).
     * @param data  the data.
     *
     * @return The dataset.
     */
    public static CategoryDataset createCategoryDataset(Comparable[] rowKeys,
            Comparable[] columnKeys, double[][] data) {

        ParamChecks.nullNotPermitted(rowKeys, "rowKeys");
        ParamChecks.nullNotPermitted(columnKeys, "columnKeys");
        if (ArrayUtilities.hasDuplicateItems(rowKeys)) {
            throw new IllegalArgumentException("Duplicate items in 'rowKeys'.");
        }
        if (ArrayUtilities.hasDuplicateItems(columnKeys)) {
            throw new IllegalArgumentException(
                    "Duplicate items in 'columnKeys'.");
        }
        if (rowKeys.length != data.length) {
            throw new IllegalArgumentException(
                "The number of row keys does not match the number of rows in "
                + "the data array.");
        }
        int columnCount = 0;
        for (double[] aData : data) {
            columnCount = Math.max(columnCount, aData.length);
        }
        if (columnKeys.length != columnCount) {
            throw new IllegalArgumentException(
                "The number of column keys does not match the number of "
                + "columns in the data array.");
        }

        // now do the work...
        DefaultCategoryDataset result = new DefaultCategoryDataset();
        for (int r = 0; r < data.length; r++) {
            Comparable rowKey = rowKeys[r];
            for (int c = 0; c < data[r].length; c++) {
                Comparable columnKey = columnKeys[c];
                result.addValue(new Double(data[r][c]), rowKey, columnKey);
            }
        }
        return result;

    }

    /**
     * Creates a {@link CategoryDataset} by copying the data from the supplied
     * {@link KeyedValues} instance.
     *
     * @param rowKey  the row key (<code>null</code> not permitted).
     * @param rowData  the row data (<code>null</code> not permitted).
     *
     * @return A dataset.
     */
    public static CategoryDataset createCategoryDataset(Comparable rowKey,
                                                        KeyedValues rowData) {
        ParamChecks.nullNotPermitted(rowKey, "rowKey");
        ParamChecks.nullNotPermitted(rowData, "rowData");

        DefaultCategoryDataset result = new DefaultCategoryDataset();
        for (int i = 0; i < rowData.getItemCount(); i++) {
            result.addValue(rowData.getValue(i), rowKey, rowData.getKey(i));
        }
        return result;

    }

    /**
     * Creates an {@link XYDataset} by sampling the specified function over a
     * fixed range.
     *
     * @param f  the function (<code>null</code> not permitted).
     * @param start  the start value for the range.
     * @param end  the end value for the range.
     * @param samples  the number of sample points (must be > 1).
     * @param seriesKey  the key to give the resulting series
     *                   (<code>null</code> not permitted).
     *
     * @return A dataset.
     */
    public static XYDataset sampleFunction2D(Function2D f, double start,
            double end, int samples, Comparable seriesKey) {

        // defer argument checking
        XYSeries series = sampleFunction2DToSeries(f, start, end, samples,
                seriesKey);
        XYSeriesCollection collection = new XYSeriesCollection(series);
        return collection;
    }

    /**
     * Creates an {@link XYSeries} by sampling the specified function over a
     * fixed range.
     *
     * @param f  the function (<code>null</code> not permitted).
     * @param start  the start value for the range.
     * @param end  the end value for the range.
     * @param samples  the number of sample points (must be > 1).
     * @param seriesKey  the key to give the resulting series
     *                   (<code>null</code> not permitted).
     *
     * @return A series.
     *
     * @since 1.0.13
     */
    public static XYSeries sampleFunction2DToSeries(Function2D f,
            double start, double end, int samples, Comparable seriesKey) {

        ParamChecks.nullNotPermitted(f, "f");
        ParamChecks.nullNotPermitted(seriesKey, "seriesKey");
        if (start >= end) {
            throw new IllegalArgumentException("Requires 'start' < 'end'.");
        }
        if (samples < 2) {
            throw new IllegalArgumentException("Requires 'samples' > 1");
        }

        XYSeries series = new XYSeries(seriesKey);
        double step = (end - start) / (samples - 1);
        for (int i = 0; i < samples; i++) {
            double x = start + (step * i);
            series.add(x, f.getValue(x));
        }
        return series;
    }

    /**
     * Returns <code>true</code> if the dataset is empty (or <code>null</code>),
     * and <code>false</code> otherwise.
     *
     * @param dataset  the dataset (<code>null</code> permitted).
     *
     * @return A boolean.
     */
    public static boolean isEmptyOrNull(PieDataset dataset) {

        if (dataset == null) {
            return true;
        }

        int itemCount = dataset.getItemCount();
        if (itemCount == 0) {
            return true;
        }

        for (int item = 0; item < itemCount; item++) {
            Number y = dataset.getValue(item);
            if (y != null) {
                double yy = y.doubleValue();
                if (yy > 0.0) {
                    return false;
                }
            }
        }

        return true;

    }

    /**
     * Returns <code>true</code> if the dataset is empty (or <code>null</code>),
     * and <code>false</code> otherwise.
     *
     * @param dataset  the dataset (<code>null</code> permitted).
     *
     * @return A boolean.
     */
    public static boolean isEmptyOrNull(CategoryDataset dataset) {

        if (dataset == null) {
            return true;
        }

        int rowCount = dataset.getRowCount();
        int columnCount = dataset.getColumnCount();
        if (rowCount == 0 || columnCount == 0) {
            return true;
        }

        for (int r = 0; r < rowCount; r++) {
            for (int c = 0; c < columnCount; c++) {
                if (dataset.getValue(r, c) != null) {
                    return false;
                }

            }
        }

        return true;

    }

    /**
     * Returns <code>true</code> if the dataset is empty (or <code>null</code>),
     * and <code>false</code> otherwise.
     *
     * @param dataset  the dataset (<code>null</code> permitted).
     *
     * @return A boolean.
     */
    public static boolean isEmptyOrNull(XYDataset dataset) {
        if (dataset != null) {
            for (int s = 0; s < dataset.getSeriesCount(); s++) {
                if (dataset.getItemCount(s) > 0) {
                    return false;
                }
            }
        }
        return true;
    }

    /**
     * Returns the range of values in the domain (x-values) of a dataset.
     *
     * @param dataset  the dataset (<code>null</code> not permitted).
     *
     * @return The range of values (possibly <code>null</code>).
     */
    public static Range findDomainBounds(XYDataset dataset) {
        return findDomainBounds(dataset, true);
    }

    /**
     * Returns the range of values in the domain (x-values) of a dataset.
     *
     * @param dataset  the dataset (<code>null</code> not permitted).
     * @param includeInterval  determines whether or not the x-interval is taken
     *                         into account (only applies if the dataset is an
     *                         {@link IntervalXYDataset}).
     *
     * @return The range of values (possibly <code>null</code>).
     */
    public static Range findDomainBounds(XYDataset dataset,
                                         boolean includeInterval) {

        ParamChecks.nullNotPermitted(dataset, "dataset");

        Range result;
        // if the dataset implements DomainInfo, life is easier
        if (dataset instanceof DomainInfo) {
            DomainInfo info = (DomainInfo) dataset;
            result = info.getDomainBounds(includeInterval);
        }
        else {
            result = iterateDomainBounds(dataset, includeInterval);
        }
        return result;

    }

    /**
     * Returns the bounds of the x-values in the specified <code>dataset</code>
     * taking into account only the visible series and including any x-interval
     * if requested.
     *
     * @param dataset  the dataset (<code>null</code> not permitted).
     * @param visibleSeriesKeys  the visible series keys (<code>null</code>
     *     not permitted).
     * @param includeInterval  include the x-interval (if any)?
     *
     * @return The bounds (or <code>null</code> if the dataset contains no
     *     values.
     *
     * @since 1.0.13
     */
    public static Range findDomainBounds(XYDataset dataset,
            List<Comparable> visibleSeriesKeys, boolean includeInterval) {
        ParamChecks.nullNotPermitted(dataset, "dataset");
        Range result;
        if (dataset instanceof XYDomainInfo) {
            XYDomainInfo info = (XYDomainInfo) dataset;
            result = info.getDomainBounds(visibleSeriesKeys, includeInterval);
        }
        else {
            result = iterateToFindDomainBounds(dataset, visibleSeriesKeys,
                    includeInterval);
        }
        return result;
    }

    /**
     * Iterates over the items in an {@link XYDataset} to find
     * the range of x-values.  If the dataset is an instance of
     * {@link IntervalXYDataset}, the starting and ending x-values
     * will be used for the bounds calculation.
     *
     * @param dataset  the dataset (<code>null</code> not permitted).
     *
     * @return The range (possibly <code>null</code>).
     */
    public static Range iterateDomainBounds(XYDataset dataset) {
        return iterateDomainBounds(dataset, true);
    }

    /**
     * Iterates over the items in an {@link XYDataset} to find
     * the range of x-values.
     *
     * @param dataset  the dataset (<code>null</code> not permitted).
     * @param includeInterval  a flag that determines, for an
     *          {@link IntervalXYDataset}, whether the x-interval or just the
     *          x-value is used to determine the overall range.
     *
     * @return The range (possibly <code>null</code>).
     */
    public static Range iterateDomainBounds(XYDataset dataset,
                                            boolean includeInterval) {
        ParamChecks.nullNotPermitted(dataset, "dataset");
        double minimum = Double.POSITIVE_INFINITY;
        double maximum = Double.NEGATIVE_INFINITY;
        int seriesCount = dataset.getSeriesCount();
        double lvalue;
        double uvalue;
        if (includeInterval && dataset instanceof IntervalXYDataset) {
            IntervalXYDataset intervalXYData = (IntervalXYDataset) dataset;
            for (int series = 0; series < seriesCount; series++) {
                int itemCount = dataset.getItemCount(series);
                for (int item = 0; item < itemCount; item++) {
                    double value = intervalXYData.getXValue(series, item);
                    lvalue = intervalXYData.getStartXValue(series, item);
                    uvalue = intervalXYData.getEndXValue(series, item);
                    if (!Double.isNaN(value)) {
                        minimum = Math.min(minimum, value);
                        maximum = Math.max(maximum, value);
                    }
                    if (!Double.isNaN(lvalue)) {
                        minimum = Math.min(minimum, lvalue);
                        maximum = Math.max(maximum, lvalue);
                    }
                    if (!Double.isNaN(uvalue)) {
                        minimum = Math.min(minimum, uvalue);
                        maximum = Math.max(maximum, uvalue);
                    }
                }
            }
        }
        else {
            for (int series = 0; series < seriesCount; series++) {
                int itemCount = dataset.getItemCount(series);
                for (int item = 0; item < itemCount; item++) {
                    lvalue = dataset.getXValue(series, item);
                    uvalue = lvalue;
                    if (!Double.isNaN(lvalue)) {
                        minimum = Math.min(minimum, lvalue);
                        maximum = Math.max(maximum, uvalue);
                    }
                }
            }
        }
        if (minimum > maximum) {
            return null;
        }
        else {
            return new Range(minimum, maximum);
        }
    }

    /**
     * Returns the range of values in the range for the dataset.
     *
     * @param dataset  the dataset (<code>null</code> not permitted).
     *
     * @return The range (possibly <code>null</code>).
     */
    public static Range findRangeBounds(CategoryDataset dataset) {
        return findRangeBounds(dataset, true);
    }

    /**
     * Returns the range of values in the range for the dataset.
     *
     * @param dataset  the dataset (<code>null</code> not permitted).
     * @param includeInterval  a flag that determines whether or not the
     *                         y-interval is taken into account.
     *
     * @return The range (possibly <code>null</code>).
     */
    public static Range findRangeBounds(CategoryDataset dataset,
                                        boolean includeInterval) {
        ParamChecks.nullNotPermitted(dataset, "dataset");
        Range result;
        if (dataset instanceof RangeInfo) {
            RangeInfo info = (RangeInfo) dataset;
            result = info.getRangeBounds(includeInterval);
        }
        else {
            result = iterateRangeBounds(dataset, includeInterval);
        }
        return result;
    }

    /**
     * Finds the bounds of the y-values in the specified dataset, including
     * only those series that are listed in visibleSeriesKeys.
     *
     * @param dataset  the dataset (<code>null</code> not permitted).
     * @param visibleSeriesKeys  the keys for the visible series
     *     (<code>null</code> not permitted).
     * @param includeInterval  include the y-interval (if the dataset has a
     *     y-interval).
     *
     * @return The data bounds.
     *
     * @since 1.0.13
     */
    public static Range findRangeBounds(CategoryDataset dataset,
            List<Comparable> visibleSeriesKeys, boolean includeInterval) {
        ParamChecks.nullNotPermitted(dataset, "dataset");
        ParamChecks.nullNotPermitted(visibleSeriesKeys, "visibleSeriesKeys");
        Range result;
        if (dataset instanceof CategoryRangeInfo) {
            CategoryRangeInfo info = (CategoryRangeInfo) dataset;
            result = info.getRangeBounds(visibleSeriesKeys, includeInterval);
        }
        else {
            result = iterateToFindRangeBounds(dataset, visibleSeriesKeys,
                    includeInterval);
        }
        return result;
    }

    /**
     * Returns the range of values in the range for the dataset.  This method
     * is the partner for the {@link #findDomainBounds(XYDataset)} method.
     *
     * @param dataset  the dataset (<code>null</code> not permitted).
     *
     * @return The range (possibly <code>null</code>).
     */
    public static Range findRangeBounds(XYDataset dataset) {
        return findRangeBounds(dataset, true);
    }

    /**
     * Returns the range of values in the range for the dataset.  This method
     * is the partner for the {@link #findDomainBounds(XYDataset, boolean)}
     * method.
     *
     * @param dataset  the dataset (<code>null</code> not permitted).
     * @param includeInterval  a flag that determines whether or not the
     *                         y-interval is taken into account.
     *
     * @return The range (possibly <code>null</code>).
     */
    public static Range findRangeBounds(XYDataset dataset,
                                        boolean includeInterval) {
        ParamChecks.nullNotPermitted(dataset, "dataset");
        Range result;
        if (dataset instanceof RangeInfo) {
            RangeInfo info = (RangeInfo) dataset;
            result = info.getRangeBounds(includeInterval);
        }
        else {
            result = iterateRangeBounds(dataset, includeInterval);
        }
        return result;
    }

    /**
     * Finds the bounds of the y-values in the specified dataset, including
     * only those series that are listed in visibleSeriesKeys, and those items
     * whose x-values fall within the specified range.
     *
     * @param dataset  the dataset (<code>null</code> not permitted).
     * @param visibleSeriesKeys  the keys for the visible series
     *     (<code>null</code> not permitted).
     * @param xRange  the x-range (<code>null</code> not permitted).
     * @param includeInterval  include the y-interval (if the dataset has a
     *     y-interval).
     *
     * @return The data bounds.
     *
     * @since 1.0.13
     */
    public static Range findRangeBounds(XYDataset dataset,
            List<Comparable> visibleSeriesKeys, Range xRange, boolean includeInterval) {
        ParamChecks.nullNotPermitted(dataset, "dataset");
        Range result;
        if (dataset instanceof XYRangeInfo) {
            XYRangeInfo info = (XYRangeInfo) dataset;
            result = info.getRangeBounds(visibleSeriesKeys, xRange,
                    includeInterval);
        }
        else {
            result = iterateToFindRangeBounds(dataset, visibleSeriesKeys,
                    xRange, includeInterval);
        }
        return result;
    }

    /**
     * Iterates over the data item of the category dataset to find
     * the range bounds.
     *
     * @param dataset  the dataset (<code>null</code> not permitted).
     *
     * @return The range (possibly <code>null</code>).
     *
     * @since 1.0.10
     */
    public static Range iterateRangeBounds(CategoryDataset dataset) {
        return iterateRangeBounds(dataset, true);
    }

    /**
     * Iterates over the data item of the category dataset to find
     * the range bounds.
     *
     * @param dataset  the dataset (<code>null</code> not permitted).
     * @param includeInterval  a flag that determines whether or not the
     *                         y-interval is taken into account.
     *
     * @return The range (possibly <code>null</code>).
     *
     * @since 1.0.10
     */
    public static Range iterateRangeBounds(CategoryDataset dataset,
            boolean includeInterval) {
        double minimum = Double.POSITIVE_INFINITY;
        double maximum = Double.NEGATIVE_INFINITY;
        int rowCount = dataset.getRowCount();
        int columnCount = dataset.getColumnCount();
        if (includeInterval && dataset instanceof IntervalCategoryDataset) {
            // handle the special case where the dataset has y-intervals that
            // we want to measure
            IntervalCategoryDataset icd = (IntervalCategoryDataset) dataset;
            Number value, lvalue, uvalue;
            for (int row = 0; row < rowCount; row++) {
                for (int column = 0; column < columnCount; column++) {
                    value = icd.getValue(row, column);
                    double v;
                    if ((value != null)
                            && !Double.isNaN(v = value.doubleValue())) {
                        minimum = Math.min(v, minimum);
                        maximum = Math.max(v, maximum);
                    }
                    lvalue = icd.getStartValue(row, column);
                    if (lvalue != null
                            && !Double.isNaN(v = lvalue.doubleValue())) {
                        minimum = Math.min(v, minimum);
                        maximum = Math.max(v, maximum);
                    }
                    uvalue = icd.getEndValue(row, column);
                    if (uvalue != null
                            && !Double.isNaN(v = uvalue.doubleValue())) {
                        minimum = Math.min(v, minimum);
                        maximum = Math.max(v, maximum);
                    }
                }
            }
        }
        else {
            // handle the standard case (plain CategoryDataset)
            for (int row = 0; row < rowCount; row++) {
                for (int column = 0; column < columnCount; column++) {
                    Number value = dataset.getValue(row, column);
                    if (value != null) {
                        double v = value.doubleValue();
                        if (!Double.isNaN(v)) {
                            minimum = Math.min(minimum, v);
                            maximum = Math.max(maximum, v);
                        }
                    }
                }
            }
        }
        if (minimum == Double.POSITIVE_INFINITY) {
            return null;
        }
        else {
            return new Range(minimum, maximum);
        }
    }

    /**
     * Iterates over the data item of the category dataset to find
     * the range bounds.
     *
     * @param dataset  the dataset (<code>null</code> not permitted).
     * @param includeInterval  a flag that determines whether or not the
     *                         y-interval is taken into account.
     * @param visibleSeriesKeys  the visible series keys.
     *
     * @return The range (possibly <code>null</code>).
     *
     * @since 1.0.13
     */
    public static Range iterateToFindRangeBounds(CategoryDataset dataset,
            List<Comparable> visibleSeriesKeys, boolean includeInterval) {

        ParamChecks.nullNotPermitted(dataset, "dataset");
        ParamChecks.nullNotPermitted(visibleSeriesKeys, "visibleSeriesKeys");

        double minimum = Double.POSITIVE_INFINITY;
        double maximum = Double.NEGATIVE_INFINITY;
        int columnCount = dataset.getColumnCount();
        if (includeInterval
                && dataset instanceof BoxAndWhiskerCategoryDataset) {
            // handle special case of BoxAndWhiskerDataset
            BoxAndWhiskerCategoryDataset bx
                    = (BoxAndWhiskerCategoryDataset) dataset;
            for (Comparable seriesKey : visibleSeriesKeys) {
                int series = dataset.getRowIndex(seriesKey);
                int itemCount = dataset.getColumnCount();
                for (int item = 0; item < itemCount; item++) {
                    Number lvalue = bx.getMinRegularValue(series, item);
                    if (lvalue == null) {
                        lvalue = bx.getValue(series, item);
                    }
                    Number uvalue = bx.getMaxRegularValue(series, item);
                    if (uvalue == null) {
                        uvalue = bx.getValue(series, item);
                    }
                    if (lvalue != null) {
                        minimum = Math.min(minimum, lvalue.doubleValue());
                    }
                    if (uvalue != null) {
                        maximum = Math.max(maximum, uvalue.doubleValue());
                    }
                }
            }
        }
        else if (includeInterval
                && dataset instanceof IntervalCategoryDataset) {
            // handle the special case where the dataset has y-intervals that
            // we want to measure
            IntervalCategoryDataset icd = (IntervalCategoryDataset) dataset;
            Number lvalue, uvalue;
            for (Comparable seriesKey : visibleSeriesKeys) {
                int series = dataset.getRowIndex(seriesKey);
                for (int column = 0; column < columnCount; column++) {
                    lvalue = icd.getStartValue(series, column);
                    uvalue = icd.getEndValue(series, column);
                    if (lvalue != null && !Double.isNaN(lvalue.doubleValue())) {
                        minimum = Math.min(minimum, lvalue.doubleValue());
                    }
                    if (uvalue != null && !Double.isNaN(uvalue.doubleValue())) {
                        maximum = Math.max(maximum, uvalue.doubleValue());
                    }
                }
            }
        }
        else if (includeInterval
                && dataset instanceof MultiValueCategoryDataset) {
            // handle the special case where the dataset has y-intervals that
            // we want to measure
            MultiValueCategoryDataset mvcd
                    = (MultiValueCategoryDataset) dataset;
            for (Comparable seriesKey : visibleSeriesKeys) {
                int series = dataset.getRowIndex(seriesKey);
                for (int column = 0; column < columnCount; column++) {
                    List<Number> values = mvcd.getValues(series, column);
                    for (Number o : values) {
                        double v = o.doubleValue();
                        if (!Double.isNaN(v)) {
                            minimum = Math.min(minimum, v);
                            maximum = Math.max(maximum, v);
                        }
                    }
                }
            }
        }
        else if (includeInterval
                && dataset instanceof StatisticalCategoryDataset) {
            // handle the special case where the dataset has y-intervals that
            // we want to measure
            StatisticalCategoryDataset scd
                    = (StatisticalCategoryDataset) dataset;
            for (Comparable seriesKey : visibleSeriesKeys) {
                int series = dataset.getRowIndex(seriesKey);
                for (int column = 0; column < columnCount; column++) {
                    Number meanN = scd.getMeanValue(series, column);
                    if (meanN != null) {
                        double std = 0.0;
                        Number stdN = scd.getStdDevValue(series, column);
                        if (stdN != null) {
                            std = stdN.doubleValue();
                            if (Double.isNaN(std)) {
                                std = 0.0;
                            }
                        }
                        double mean = meanN.doubleValue();
                        if (!Double.isNaN(mean)) {
                            minimum = Math.min(minimum, mean - std);
                            maximum = Math.max(maximum, mean + std);
                        }
                    }
                }
            }
        }
        else {
            // handle the standard case (plain CategoryDataset)
            for (Comparable seriesKey : visibleSeriesKeys) {
                int series = dataset.getRowIndex(seriesKey);
                for (int column = 0; column < columnCount; column++) {
                    Number value = dataset.getValue(series, column);
                    if (value != null) {
                        double v = value.doubleValue();
                        if (!Double.isNaN(v)) {
                            minimum = Math.min(minimum, v);
                            maximum = Math.max(maximum, v);
                        }
                    }
                }
            }
        }
        if (minimum == Double.POSITIVE_INFINITY) {
            return null;
        }
        else {
            return new Range(minimum, maximum);
        }
    }

    /**
     * Iterates over the data item of the xy dataset to find
     * the range bounds.
     *
     * @param dataset  the dataset (<code>null</code> not permitted).
     *
     * @return The range (possibly <code>null</code>).
     *
     * @since 1.0.10
     */
    public static Range iterateRangeBounds(XYDataset dataset) {
        return iterateRangeBounds(dataset, true);
    }

    /**
     * Iterates over the data items of the xy dataset to find
     * the range bounds.
     *
     * @param dataset  the dataset (<code>null</code> not permitted).
     * @param includeInterval  a flag that determines, for an
     *          {@link IntervalXYDataset}, whether the y-interval or just the
     *          y-value is used to determine the overall range.
     *
     * @return The range (possibly <code>null</code>).
     *
     * @since 1.0.10
     */
    public static Range iterateRangeBounds(XYDataset dataset,
            boolean includeInterval) {
        double minimum = Double.POSITIVE_INFINITY;
        double maximum = Double.NEGATIVE_INFINITY;
        int seriesCount = dataset.getSeriesCount();

        // handle three cases by dataset type
        if (includeInterval && dataset instanceof IntervalXYDataset) {
            // handle special case of IntervalXYDataset
            IntervalXYDataset ixyd = (IntervalXYDataset) dataset;
            for (int series = 0; series < seriesCount; series++) {
                int itemCount = dataset.getItemCount(series);
                for (int item = 0; item < itemCount; item++) {
                    double value = ixyd.getYValue(series, item);
                    double lvalue = ixyd.getStartYValue(series, item);
                    double uvalue = ixyd.getEndYValue(series, item);
                    if (!Double.isNaN(value)) {
                        minimum = Math.min(minimum, value);
                        maximum = Math.max(maximum, value);
                    }
                    if (!Double.isNaN(lvalue)) {
                        minimum = Math.min(minimum, lvalue);
                        maximum = Math.max(maximum, lvalue);
                    }
                    if (!Double.isNaN(uvalue)) {
                        minimum = Math.min(minimum, uvalue);
                        maximum = Math.max(maximum, uvalue);
                    }
                }
            }
        }
        else if (includeInterval && dataset instanceof OHLCDataset) {
            // handle special case of OHLCDataset
            OHLCDataset ohlc = (OHLCDataset) dataset;
            for (int series = 0; series < seriesCount; series++) {
                int itemCount = dataset.getItemCount(series);
                for (int item = 0; item < itemCount; item++) {
                    double lvalue = ohlc.getLowValue(series, item);
                    double uvalue = ohlc.getHighValue(series, item);
                    if (!Double.isNaN(lvalue)) {
                        minimum = Math.min(minimum, lvalue);
                    }
                    if (!Double.isNaN(uvalue)) {
                        maximum = Math.max(maximum, uvalue);
                    }
                }
            }
        }
        else {
            // standard case - plain XYDataset
            for (int series = 0; series < seriesCount; series++) {
                int itemCount = dataset.getItemCount(series);
                for (int item = 0; item < itemCount; item++) {
                    double value = dataset.getYValue(series, item);
                    if (!Double.isNaN(value)) {
                        minimum = Math.min(minimum, value);
                        maximum = Math.max(maximum, value);
                    }
                }
            }
        }
        if (minimum == Double.POSITIVE_INFINITY) {
            return null;
        }
        else {
            return new Range(minimum, maximum);
        }
    }

    /**
     * Returns the range of values in the z-dimension for the dataset. This
     * method is the partner for the {@link #findRangeBounds(XYDataset)}
     * and {@link #findDomainBounds(XYDataset)} methods.
     *
     * @param dataset  the dataset (<code>null</code> not permitted).
     *
     * @return The range (possibly <code>null</code>).
     */
    public static Range findZBounds(XYZDataset dataset) {
        return findZBounds(dataset, true);
    }

    /**
     * Returns the range of values in the z-dimension for the dataset.  This
     * method is the partner for the
     * {@link #findRangeBounds(XYDataset, boolean)} and
     * {@link #findDomainBounds(XYDataset, boolean)} methods.
     *
     * @param dataset  the dataset (<code>null</code> not permitted).
     * @param includeInterval  a flag that determines whether or not the
     *                         z-interval is taken into account.
     *
     * @return The range (possibly <code>null</code>).
     */
    public static Range findZBounds(XYZDataset dataset,
                                        boolean includeInterval) {
        ParamChecks.nullNotPermitted(dataset, "dataset");
        Range result = iterateZBounds(dataset, includeInterval);
        return result;
    }

    /**
     * Finds the bounds of the z-values in the specified dataset, including
     * only those series that are listed in visibleSeriesKeys, and those items
     * whose x-values fall within the specified range.
     *
     * @param dataset  the dataset (<code>null</code> not permitted).
     * @param visibleSeriesKeys  the keys for the visible series
     *     (<code>null</code> not permitted).
     * @param xRange  the x-range (<code>null</code> not permitted).
     * @param includeInterval  include the z-interval (if the dataset has a
     *     z-interval).
     *
     * @return The data bounds.
     */
    public static Range findZBounds(XYZDataset dataset,
            List<Comparable> visibleSeriesKeys, Range xRange, boolean includeInterval) {
        ParamChecks.nullNotPermitted(dataset, "dataset");
        Range result = iterateToFindZBounds(dataset, visibleSeriesKeys,
                    xRange, includeInterval);
        return result;
    }

    /**
     * Iterates over the data item of the xyz dataset to find
     * the z-dimension bounds.
     *
     * @param dataset  the dataset (<code>null</code> not permitted).
     *
     * @return The range (possibly <code>null</code>).
     */
    public static Range iterateZBounds(XYZDataset dataset) {
        return iterateZBounds(dataset, true);
    }

    /**
     * Iterates over the data items of the xyz dataset to find
     * the z-dimension bounds.
     *
     * @param dataset  the dataset (<code>null</code> not permitted).
     * @param includeInterval  include the z-interval (if the dataset has a
     *     z-interval.
     *
     * @return The range (possibly <code>null</code>).
     */
    public static Range iterateZBounds(XYZDataset dataset,
            boolean includeInterval) {
        double minimum = Double.POSITIVE_INFINITY;
        double maximum = Double.NEGATIVE_INFINITY;
        int seriesCount = dataset.getSeriesCount();

        for (int series = 0; series < seriesCount; series++) {
            int itemCount = dataset.getItemCount(series);
            for (int item = 0; item < itemCount; item++) {
                double value = dataset.getZValue(series, item);
                if (!Double.isNaN(value)) {
                    minimum = Math.min(minimum, value);
                    maximum = Math.max(maximum, value);
                }
            }
        }

        if (minimum == Double.POSITIVE_INFINITY) {
            return null;
        }
        else {
            return new Range(minimum, maximum);
        }
    }

    /**
     * Returns the range of x-values in the specified dataset for the
     * data items belonging to the visible series.
     *
     * @param dataset  the dataset (<code>null</code> not permitted).
     * @param visibleSeriesKeys  the visible series keys (<code>null</code> not
     *     permitted).
     * @param includeInterval  a flag that determines whether or not the
     *     y-interval for the dataset is included (this only applies if the
     *     dataset is an instance of IntervalXYDataset).
     *
     * @return The x-range (possibly <code>null</code>).
     *
     * @since 1.0.13
     */
    public static Range iterateToFindDomainBounds(XYDataset dataset,
            List<Comparable> visibleSeriesKeys, boolean includeInterval) {

        ParamChecks.nullNotPermitted(dataset, "dataset");
        ParamChecks.nullNotPermitted(visibleSeriesKeys, "visibleSeriesKeys");

        double minimum = Double.POSITIVE_INFINITY;
        double maximum = Double.NEGATIVE_INFINITY;

        if (includeInterval && dataset instanceof IntervalXYDataset) {
            // handle special case of IntervalXYDataset
            IntervalXYDataset ixyd = (IntervalXYDataset) dataset;
            for (Comparable seriesKey : visibleSeriesKeys) {
                int series = dataset.indexOf(seriesKey);
                int itemCount = dataset.getItemCount(series);
                for (int item = 0; item < itemCount; item++) {
                    double lvalue = ixyd.getStartXValue(series, item);
                    double uvalue = ixyd.getEndXValue(series, item);
                    if (!Double.isNaN(lvalue)) {
                        minimum = Math.min(minimum, lvalue);
                    }
                    if (!Double.isNaN(uvalue)) {
                        maximum = Math.max(maximum, uvalue);
                    }
                }
            }
        }
        else {
            // standard case - plain XYDataset
            for (Comparable seriesKey : visibleSeriesKeys) {
                int series = dataset.indexOf(seriesKey);
                int itemCount = dataset.getItemCount(series);
                for (int item = 0; item < itemCount; item++) {
                    double x = dataset.getXValue(series, item);
                    if (!Double.isNaN(x)) {
                        minimum = Math.min(minimum, x);
                        maximum = Math.max(maximum, x);
                    }
                }
            }
        }

        if (minimum == Double.POSITIVE_INFINITY) {
            return null;
        }
        else {
            return new Range(minimum, maximum);
        }
    }

    /**
     * Returns the range of y-values in the specified dataset for the
     * data items belonging to the visible series and with x-values in the
     * given range.
     *
     * @param dataset  the dataset (<code>null</code> not permitted).
     * @param visibleSeriesKeys  the visible series keys (<code>null</code> not
     *     permitted).
     * @param xRange  the x-range (<code>null</code> not permitted).
     * @param includeInterval  a flag that determines whether or not the
     *     y-interval for the dataset is included (this only applies if the
     *     dataset is an instance of IntervalXYDataset).
     *
     * @return The y-range (possibly <code>null</code>).
     *
     * @since 1.0.13
     */
    public static Range iterateToFindRangeBounds(XYDataset dataset,
            List<Comparable> visibleSeriesKeys, Range xRange, boolean includeInterval) {

        ParamChecks.nullNotPermitted(dataset, "dataset");
        ParamChecks.nullNotPermitted(visibleSeriesKeys, "visibleSeriesKeys");
        ParamChecks.nullNotPermitted(xRange, "xRange");

        double minimum = Double.POSITIVE_INFINITY;
        double maximum = Double.NEGATIVE_INFINITY;

        // handle three cases by dataset type
        if (includeInterval && dataset instanceof OHLCDataset) {
            // handle special case of OHLCDataset
            OHLCDataset ohlc = (OHLCDataset) dataset;
            for (Comparable seriesKey : visibleSeriesKeys) {
                int series = dataset.indexOf(seriesKey);
                int itemCount = dataset.getItemCount(series);
                for (int item = 0; item < itemCount; item++) {
                    double x = ohlc.getXValue(series, item);
                    if (xRange.contains(x)) {
                        double lvalue = ohlc.getLowValue(series, item);
                        double uvalue = ohlc.getHighValue(series, item);
                        if (!Double.isNaN(lvalue)) {
                            minimum = Math.min(minimum, lvalue);
                        }
                        if (!Double.isNaN(uvalue)) {
                            maximum = Math.max(maximum, uvalue);
                        }
                    }
                }
            }
        }
        else if (includeInterval && dataset instanceof BoxAndWhiskerXYDataset) {
            // handle special case of BoxAndWhiskerXYDataset
            BoxAndWhiskerXYDataset bx = (BoxAndWhiskerXYDataset) dataset;
            for (Comparable seriesKey : visibleSeriesKeys) {
                int series = dataset.indexOf(seriesKey);
                int itemCount = dataset.getItemCount(series);
                for (int item = 0; item < itemCount; item++) {
                    double x = bx.getXValue(series, item);
                    if (xRange.contains(x)) {
                        Number lvalue = bx.getMinRegularValue(series, item);
                        Number uvalue = bx.getMaxRegularValue(series, item);
                        if (lvalue != null) {
                            minimum = Math.min(minimum, lvalue.doubleValue());
                        }
                        if (uvalue != null) {
                            maximum = Math.max(maximum, uvalue.doubleValue());
                        }
                    }
                }
            }
        }
        else if (includeInterval && dataset instanceof IntervalXYDataset) {
            // handle special case of IntervalXYDataset
            IntervalXYDataset ixyd = (IntervalXYDataset) dataset;
            for (Comparable seriesKey : visibleSeriesKeys) {
                int series = dataset.indexOf(seriesKey);
                int itemCount = dataset.getItemCount(series);
                for (int item = 0; item < itemCount; item++) {
                    double x = ixyd.getXValue(series, item);
                    if (xRange.contains(x)) {
                        double lvalue = ixyd.getStartYValue(series, item);
                        double uvalue = ixyd.getEndYValue(series, item);
                        if (!Double.isNaN(lvalue)) {
                            minimum = Math.min(minimum, lvalue);
                        }
                        if (!Double.isNaN(uvalue)) {
                            maximum = Math.max(maximum, uvalue);
                        }
                    }
                }
            }
        }
        else {
            // standard case - plain XYDataset
            for (Comparable seriesKey : visibleSeriesKeys) {
                int series = dataset.indexOf(seriesKey);
                int itemCount = dataset.getItemCount(series);
                for (int item = 0; item < itemCount; item++) {
                    double x = dataset.getXValue(series, item);
                    double y = dataset.getYValue(series, item);
                    if (xRange.contains(x)) {
                        if (!Double.isNaN(y)) {
                            minimum = Math.min(minimum, y);
                            maximum = Math.max(maximum, y);
                        }
                    }
                }
            }
        }
        if (minimum == Double.POSITIVE_INFINITY) {
            return null;
        }
        else {
            return new Range(minimum, maximum);
        }
    }

    /**
     * Returns the range of z-values in the specified dataset for the
     * data items belonging to the visible series and with x-values in the
     * given range.
     *
     * @param dataset  the dataset (<code>null</code> not permitted).
     * @param visibleSeriesKeys  the visible series keys (<code>null</code> not
     *     permitted).
     * @param xRange  the x-range (<code>null</code> not permitted).
     * @param includeInterval  a flag that determines whether or not the
     *     z-interval for the dataset is included (this only applies if the
     *     dataset has an interval, which is currently not supported).
     *
     * @return The y-range (possibly <code>null</code>).
     */
    public static Range iterateToFindZBounds(XYZDataset dataset,
            List<Comparable> visibleSeriesKeys, Range xRange, boolean includeInterval) {

        ParamChecks.nullNotPermitted(dataset, "dataset");
        ParamChecks.nullNotPermitted(visibleSeriesKeys, "visibleSeriesKeys");
        ParamChecks.nullNotPermitted(xRange, "xRange");

        double minimum = Double.POSITIVE_INFINITY;
        double maximum = Double.NEGATIVE_INFINITY;

        for (Comparable seriesKey : visibleSeriesKeys) {
            int series = dataset.indexOf(seriesKey);
            int itemCount = dataset.getItemCount(series);
            for (int item = 0; item < itemCount; item++) {
                double x = dataset.getXValue(series, item);
                double z = dataset.getZValue(series, item);
                if (xRange.contains(x)) {
                    if (!Double.isNaN(z)) {
                        minimum = Math.min(minimum, z);
                        maximum = Math.max(maximum, z);
                    }
                }
            }
        }

        if (minimum == Double.POSITIVE_INFINITY) {
            return null;
        }
        else {
            return new Range(minimum, maximum);
        }
    }

    /**
     * Finds the minimum domain (or X) value for the specified dataset.  This
     * is easy if the dataset implements the {@link DomainInfo} interface (a
     * good idea if there is an efficient way to determine the minimum value).
     * Otherwise, it involves iterating over the entire data-set.
     * <p>
     * Returns <code>null</code> if all the data values in the dataset are
     * <code>null</code>.
     *
     * @param dataset  the dataset (<code>null</code> not permitted).
     *
     * @return The minimum value (possibly <code>null</code>).
     */
    public static Number findMinimumDomainValue(XYDataset dataset) {
        ParamChecks.nullNotPermitted(dataset, "dataset");
        Number result;
        // if the dataset implements DomainInfo, life is easy
        if (dataset instanceof DomainInfo) {
            DomainInfo info = (DomainInfo) dataset;
            return info.getDomainLowerBound(true);
        }
        else {
            double minimum = Double.POSITIVE_INFINITY;
            int seriesCount = dataset.getSeriesCount();
            for (int series = 0; series < seriesCount; series++) {
                int itemCount = dataset.getItemCount(series);
                for (int item = 0; item < itemCount; item++) {

                    double value;
                    if (dataset instanceof IntervalXYDataset) {
                        IntervalXYDataset intervalXYData
                            = (IntervalXYDataset) dataset;
                        value = intervalXYData.getStartXValue(series, item);
                    }
                    else {
                        value = dataset.getXValue(series, item);
                    }
                    if (!Double.isNaN(value)) {
                        minimum = Math.min(minimum, value);
                    }

                }
            }
            if (minimum == Double.POSITIVE_INFINITY) {
                result = null;
            }
            else {
                result = minimum;
            }
        }

        return result;
    }

    /**
     * Returns the maximum domain value for the specified dataset.  This is
     * easy if the dataset implements the {@link DomainInfo} interface (a good
     * idea if there is an efficient way to determine the maximum value).
     * Otherwise, it involves iterating over the entire data-set.  Returns
     * <code>null</code> if all the data values in the dataset are
     * <code>null</code>.
     *
     * @param dataset  the dataset (<code>null</code> not permitted).
     *
     * @return The maximum value (possibly <code>null</code>).
     */
    public static Number findMaximumDomainValue(XYDataset dataset) {
        ParamChecks.nullNotPermitted(dataset, "dataset");
        Number result;
        // if the dataset implements DomainInfo, life is easy
        if (dataset instanceof DomainInfo) {
            DomainInfo info = (DomainInfo) dataset;
            return info.getDomainUpperBound(true);
        }

        // hasn't implemented DomainInfo, so iterate...
        else {
            double maximum = Double.NEGATIVE_INFINITY;
            int seriesCount = dataset.getSeriesCount();
            for (int series = 0; series < seriesCount; series++) {
                int itemCount = dataset.getItemCount(series);
                for (int item = 0; item < itemCount; item++) {

                    double value;
                    if (dataset instanceof IntervalXYDataset) {
                        IntervalXYDataset intervalXYData
                            = (IntervalXYDataset) dataset;
                        value = intervalXYData.getEndXValue(series, item);
                    }
                    else {
                        value = dataset.getXValue(series, item);
                    }
                    if (!Double.isNaN(value)) {
                        maximum = Math.max(maximum, value);
                    }
                }
            }
            if (maximum == Double.NEGATIVE_INFINITY) {
                result = null;
            }
            else {
                result = maximum;
            }

        }

        return result;
    }

    /**
     * Returns the minimum range value for the specified dataset.  This is
     * easy if the dataset implements the {@link RangeInfo} interface (a good
     * idea if there is an efficient way to determine the minimum value).
     * Otherwise, it involves iterating over the entire data-set.  Returns
     * <code>null</code> if all the data values in the dataset are
     * <code>null</code>.
     *
     * @param dataset  the dataset (<code>null</code> not permitted).
     *
     * @return The minimum value (possibly <code>null</code>).
     */
    public static Number findMinimumRangeValue(CategoryDataset dataset) {

        ParamChecks.nullNotPermitted(dataset, "dataset");

        if (dataset instanceof RangeInfo) {
            RangeInfo info = (RangeInfo) dataset;
            return new Double(info.getRangeLowerBound(true));
        }

        // hasn't implemented RangeInfo, so we'll have to iterate...
        else {
            double minimum = Double.POSITIVE_INFINITY;
            int seriesCount = dataset.getRowCount();
            int itemCount = dataset.getColumnCount();
            for (int series = 0; series < seriesCount; series++) {
                for (int item = 0; item < itemCount; item++) {
                    Number value;
                    if (dataset instanceof IntervalCategoryDataset) {
                        IntervalCategoryDataset icd
                                = (IntervalCategoryDataset) dataset;
                        value = icd.getStartValue(series, item);
                    }
                    else {
                        value = dataset.getValue(series, item);
                    }
                    if (value != null) {
                        minimum = Math.min(minimum, value.doubleValue());
                    }
                }
            }
            if (minimum == Double.POSITIVE_INFINITY) {
                return null;
            }
            else {
                return minimum;
            }

        }

    }

    /**
     * Returns the minimum range value for the specified dataset.  This is
     * easy if the dataset implements the {@link RangeInfo} interface (a good
     * idea if there is an efficient way to determine the minimum value).
     * Otherwise, it involves iterating over the entire data-set.  Returns
     * <code>null</code> if all the data values in the dataset are
     * <code>null</code>.
     *
     * @param dataset  the dataset (<code>null</code> not permitted).
     *
     * @return The minimum value (possibly <code>null</code>).
     */
    public static Number findMinimumRangeValue(XYDataset dataset) {

        ParamChecks.nullNotPermitted(dataset, "dataset");

        // work out the minimum value...
        if (dataset instanceof RangeInfo) {
            RangeInfo info = (RangeInfo) dataset;
            return info.getRangeLowerBound(true);
        }

        // hasn't implemented RangeInfo, so we'll have to iterate...
        else {
            double minimum = Double.POSITIVE_INFINITY;
            int seriesCount = dataset.getSeriesCount();
            for (int series = 0; series < seriesCount; series++) {
                int itemCount = dataset.getItemCount(series);
                for (int item = 0; item < itemCount; item++) {

                    double value;
                    if (dataset instanceof IntervalXYDataset) {
                        IntervalXYDataset intervalXYData
                                = (IntervalXYDataset) dataset;
                        value = intervalXYData.getStartYValue(series, item);
                    }
                    else if (dataset instanceof OHLCDataset) {
                        OHLCDataset highLowData = (OHLCDataset) dataset;
                        value = highLowData.getLowValue(series, item);
                    }
                    else {
                        value = dataset.getYValue(series, item);
                    }
                    if (!Double.isNaN(value)) {
                        minimum = Math.min(minimum, value);
                    }

                }
            }
            if (minimum == Double.POSITIVE_INFINITY) {
                return null;
            }
            else {
                return minimum;
            }

        }

    }

    /**
     * Returns the maximum range value for the specified dataset.  This is easy
     * if the dataset implements the {@link RangeInfo} interface (a good idea
     * if there is an efficient way to determine the maximum value).
     * Otherwise, it involves iterating over the entire data-set.  Returns
     * <code>null</code> if all the data values are <code>null</code>.
     *
     * @param dataset  the dataset (<code>null</code> not permitted).
     *
     * @return The maximum value (possibly <code>null</code>).
     */
    public static Number findMaximumRangeValue(CategoryDataset dataset) {

        ParamChecks.nullNotPermitted(dataset, "dataset");

        // work out the minimum value...
        if (dataset instanceof RangeInfo) {
            RangeInfo info = (RangeInfo) dataset;
            return info.getRangeUpperBound(true);
        }

        // hasn't implemented RangeInfo, so we'll have to iterate...
        else {

            double maximum = Double.NEGATIVE_INFINITY;
            int seriesCount = dataset.getRowCount();
            int itemCount = dataset.getColumnCount();
            for (int series = 0; series < seriesCount; series++) {
                for (int item = 0; item < itemCount; item++) {
                    Number value;
                    if (dataset instanceof IntervalCategoryDataset) {
                        IntervalCategoryDataset icd
                            = (IntervalCategoryDataset) dataset;
                        value = icd.getEndValue(series, item);
                    }
                    else {
                        value = dataset.getValue(series, item);
                    }
                    if (value != null) {
                        maximum = Math.max(maximum, value.doubleValue());
                    }
                }
            }
            if (maximum == Double.NEGATIVE_INFINITY) {
                return null;
            }
            else {
                return maximum;
            }

        }

    }

    /**
     * Returns the maximum range value for the specified dataset.  This is
     * easy if the dataset implements the {@link RangeInfo} interface (a good
     * idea if there is an efficient way to determine the maximum value).
     * Otherwise, it involves iterating over the entire data-set.  Returns
     * <code>null</code> if all the data values are <code>null</code>.
     *
     * @param dataset  the dataset (<code>null</code> not permitted).
     *
     * @return The maximum value (possibly <code>null</code>).
     */
    public static Number findMaximumRangeValue(XYDataset dataset) {

        ParamChecks.nullNotPermitted(dataset, "dataset");

        // work out the minimum value...
        if (dataset instanceof RangeInfo) {
            RangeInfo info = (RangeInfo) dataset;
            return info.getRangeUpperBound(true);
        }

        // hasn't implemented RangeInfo, so we'll have to iterate...
        else  {

            double maximum = Double.NEGATIVE_INFINITY;
            int seriesCount = dataset.getSeriesCount();
            for (int series = 0; series < seriesCount; series++) {
                int itemCount = dataset.getItemCount(series);
                for (int item = 0; item < itemCount; item++) {
                    double value;
                    if (dataset instanceof IntervalXYDataset) {
                        IntervalXYDataset intervalXYData
                                = (IntervalXYDataset) dataset;
                        value = intervalXYData.getEndYValue(series, item);
                    }
                    else if (dataset instanceof OHLCDataset) {
                        OHLCDataset highLowData = (OHLCDataset) dataset;
                        value = highLowData.getHighValue(series, item);
                    }
                    else {
                        value = dataset.getYValue(series, item);
                    }
                    if (!Double.isNaN(value)) {
                        maximum = Math.max(maximum, value);
                    }
                }
            }
            if (maximum == Double.NEGATIVE_INFINITY) {
                return null;
            }
            else {
                return maximum;
            }

        }

    }

    /**
     * Returns the minimum and maximum values for the dataset's range
     * (y-values), assuming that the series in one category are stacked.
     *
     * @param dataset  the dataset (<code>null</code> not permitted).
     *
     * @return The range (<code>null</code> if the dataset contains no values).
     */
    public static Range findStackedRangeBounds(CategoryDataset dataset) {
        return findStackedRangeBounds(dataset, 0.0);
    }

    /**
     * Returns the minimum and maximum values for the dataset's range
     * (y-values), assuming that the series in one category are stacked.
     *
     * @param dataset  the dataset (<code>null</code> not permitted).
     * @param base  the base value for the bars.
     *
     * @return The range (<code>null</code> if the dataset contains no values).
     */
    public static Range findStackedRangeBounds(CategoryDataset dataset,
            double base) {
        ParamChecks.nullNotPermitted(dataset, "dataset");
        Range result = null;
        double minimum = Double.POSITIVE_INFINITY;
        double maximum = Double.NEGATIVE_INFINITY;
        int categoryCount = dataset.getColumnCount();
        for (int item = 0; item < categoryCount; item++) {
            double positive = base;
            double negative = base;
            int seriesCount = dataset.getRowCount();
            for (int series = 0; series < seriesCount; series++) {
                Number number = dataset.getValue(series, item);
                if (number != null) {
                    double value = number.doubleValue();
                    if (value > 0.0) {
                        positive = positive + value;
                    }
                    if (value < 0.0) {
                        negative = negative + value;
                        // '+', remember value is negative
                    }
                }
            }
            minimum = Math.min(minimum, negative);
            maximum = Math.max(maximum, positive);
        }
        if (minimum <= maximum) {
            result = new Range(minimum, maximum);
        }
        return result;

    }

    /**
     * Returns the minimum and maximum values for the dataset's range
     * (y-values), assuming that the series in one category are stacked.
     *
     * @param dataset  the dataset (<code>null</code> not permitted).
     * @param map  a structure that maps series to groups.
     *
     * @return The value range (<code>null</code> if the dataset contains no
     *         values).
     */
    public static Range findStackedRangeBounds(CategoryDataset dataset,
                                               KeyToGroupMap map) {
        ParamChecks.nullNotPermitted(dataset, "dataset");
        boolean hasValidData = false;
        Range result = null;

        // create an array holding the group indices for each series...
        int[] groupIndex = new int[dataset.getRowCount()];
        for (int i = 0; i < dataset.getRowCount(); i++) {
            groupIndex[i] = map.getGroupIndex(map.getGroup(
                    dataset.getRowKey(i)));
        }

        // minimum and maximum for each group...
        int groupCount = map.getGroupCount();
        double[] minimum = new double[groupCount];
        double[] maximum = new double[groupCount];

        int categoryCount = dataset.getColumnCount();
        for (int item = 0; item < categoryCount; item++) {
            double[] positive = new double[groupCount];
            double[] negative = new double[groupCount];
            int seriesCount = dataset.getRowCount();
            for (int series = 0; series < seriesCount; series++) {
                Number number = dataset.getValue(series, item);
                if (number != null) {
                    hasValidData = true;
                    double value = number.doubleValue();
                    if (value > 0.0) {
                        positive[groupIndex[series]]
                                 = positive[groupIndex[series]] + value;
                    }
                    if (value < 0.0) {
                        negative[groupIndex[series]]
                                 = negative[groupIndex[series]] + value;
                                 // '+', remember value is negative
                    }
                }
            }
            for (int g = 0; g < groupCount; g++) {
                minimum[g] = Math.min(minimum[g], negative[g]);
                maximum[g] = Math.max(maximum[g], positive[g]);
            }
        }
        if (hasValidData) {
            for (int j = 0; j < groupCount; j++) {
                result = Range.combine(result, new Range(minimum[j],
                        maximum[j]));
            }
        }
        return result;
    }

    /**
     * Returns the minimum value in the dataset range, assuming that values in
     * each category are "stacked".
     *
     * @param dataset  the dataset (<code>null</code> not permitted).
     *
     * @return The minimum value.
     *
     * @see #findMaximumStackedRangeValue(CategoryDataset)
     */
    public static Number findMinimumStackedRangeValue(CategoryDataset dataset) {
        ParamChecks.nullNotPermitted(dataset, "dataset");
        Number result = null;
        boolean hasValidData = false;
        double minimum = 0.0;
        int categoryCount = dataset.getColumnCount();
        for (int item = 0; item < categoryCount; item++) {
            double total = 0.0;
            int seriesCount = dataset.getRowCount();
            for (int series = 0; series < seriesCount; series++) {
                Number number = dataset.getValue(series, item);
                if (number != null) {
                    hasValidData = true;
                    double value = number.doubleValue();
                    if (value < 0.0) {
                        total = total + value;
                        // '+', remember value is negative
                    }
                }
            }
            minimum = Math.min(minimum, total);
        }
        if (hasValidData) {
            result = minimum;
        }
        return result;
    }

    /**
     * Returns the maximum value in the dataset range, assuming that values in
     * each category are "stacked".
     *
     * @param dataset  the dataset (<code>null</code> not permitted).
     *
     * @return The maximum value (possibly <code>null</code>).
     *
     * @see #findMinimumStackedRangeValue(CategoryDataset)
     */
    public static Number findMaximumStackedRangeValue(CategoryDataset dataset) {
        ParamChecks.nullNotPermitted(dataset, "dataset");
        Number result = null;
        boolean hasValidData = false;
        double maximum = 0.0;
        int categoryCount = dataset.getColumnCount();
        for (int item = 0; item < categoryCount; item++) {
            double total = 0.0;
            int seriesCount = dataset.getRowCount();
            for (int series = 0; series < seriesCount; series++) {
                Number number = dataset.getValue(series, item);
                if (number != null) {
                    hasValidData = true;
                    double value = number.doubleValue();
                    if (value > 0.0) {
                        total = total + value;
                    }
                }
            }
            maximum = Math.max(maximum, total);
        }
        if (hasValidData) {
            result = maximum;
        }
        return result;
    }

    /**
     * Returns the minimum and maximum values for the dataset's range,
     * assuming that the series are stacked.
     *
     * @param dataset  the dataset (<code>null</code> not permitted).
     *
     * @return The range ([0.0, 0.0] if the dataset contains no values).
     */
    public static Range findStackedRangeBounds(TableXYDataset dataset) {
        return findStackedRangeBounds(dataset, 0.0);
    }

    /**
     * Returns the minimum and maximum values for the dataset's range,
     * assuming that the series are stacked, using the specified base value.
     *
     * @param dataset  the dataset (<code>null</code> not permitted).
     * @param base  the base value.
     *
     * @return The range (<code>null</code> if the dataset contains no values).
     */
    public static Range findStackedRangeBounds(TableXYDataset dataset,
                                               double base) {
        ParamChecks.nullNotPermitted(dataset, "dataset");
        double minimum = base;
        double maximum = base;
        for (int itemNo = 0; itemNo < dataset.getItemCount(); itemNo++) {
            double positive = base;
            double negative = base;
            int seriesCount = dataset.getSeriesCount();
            for (int seriesNo = 0; seriesNo < seriesCount; seriesNo++) {
                double y = dataset.getYValue(seriesNo, itemNo);
                if (!Double.isNaN(y)) {
                    if (y > 0.0) {
                        positive += y;
                    }
                    else {
                        negative += y;
                    }
                }
            }
            if (positive > maximum) {
                maximum = positive;
            }
            if (negative < minimum) {
                minimum = negative;
            }
        }
        if (minimum <= maximum) {
            return new Range(minimum, maximum);
        }
        else {
            return null;
        }
    }

    /**
     * Calculates the total for the y-values in all series for a given item
     * index.
     *
     * @param dataset  the dataset (<code>null</code> not permitted).
     * @param item  the item index.
     *
     * @return The total.
     *
     * @since 1.0.5
     */
    public static double calculateStackTotal(TableXYDataset dataset, int item) {
        double total = 0.0;
        int seriesCount = dataset.getSeriesCount();
        for (int s = 0; s < seriesCount; s++) {
            double value = dataset.getYValue(s, item);
            if (!Double.isNaN(value)) {
                total = total + value;
            }
        }
        return total;
    }

    /**
     * Calculates the range of values for a dataset where each item is the
     * running total of the items for the current series.
     *
     * @param dataset  the dataset (<code>null</code> not permitted).
     *
     * @return The range.
     *
     * @see #findRangeBounds(CategoryDataset)
     */
    public static Range findCumulativeRangeBounds(CategoryDataset dataset) {
        ParamChecks.nullNotPermitted(dataset, "dataset");
        boolean allItemsNull = true; // we'll set this to false if there is at
                                     // least one non-null data item...
        double minimum = 0.0;
        double maximum = 0.0;
        for (int row = 0; row < dataset.getRowCount(); row++) {
            double runningTotal = 0.0;
            for (int column = 0; column <= dataset.getColumnCount() - 1;
                 column++) {
                Number n = dataset.getValue(row, column);
                if (n != null) {
                    allItemsNull = false;
                    double value = n.doubleValue();
                    if (!Double.isNaN(value)) {
                        runningTotal = runningTotal + value;
                        minimum = Math.min(minimum, runningTotal);
                        maximum = Math.max(maximum, runningTotal);
                    }
                }
            }
        }
        if (!allItemsNull) {
            return new Range(minimum, maximum);
        }
        else {
            return null;
        }
    }

    /**
     * Returns the interpolated value of y that corresponds to the specified
     * x-value in the given series.  If the x-value falls outside the range of
     * x-values for the dataset, this method returns <code>Double.NaN</code>.
     * 
     * @param dataset  the dataset (<code>null</code> not permitted).
     * @param series  the series index.
     * @param x  the x-value.
     * 
     * @return The y value.
     * 
     * @since 1.0.16
     */
    public static double findYValue(XYDataset dataset, int series, double x) {
        // delegate null check on dataset
        int[] indices = findItemIndicesForX(dataset, series, x);
        if (indices[0] == -1) {
            return Double.NaN;
        }
        if (indices[0] == indices[1]) {
            return dataset.getYValue(series, indices[0]);
        }
        double x0 = dataset.getXValue(series, indices[0]);
        double x1 = dataset.getXValue(series, indices[1]);
        double y0 = dataset.getYValue(series, indices[0]);
        double y1 = dataset.getYValue(series, indices[1]);
        return y0 + (y1 - y0) * (x - x0) / (x1 - x0);
    }
    
    /**
     * Finds the indices of the the items in the dataset that span the 
     * specified x-value.  There are three cases for the return value:
     * <ul>
     * <li>there is an exact match for the x-value at index i 
     * (returns <code>int[] {i, i}</code>);</li>
     * <li>the x-value falls between two (adjacent) items at index i and i+1 
     * (returns <code>int[] {i, i+1}</code>);</li>
     * <li>the x-value falls outside the domain bounds, in which case the 
     *    method returns <code>int[] {-1, -1}</code>.</li>
     * </ul>
     * @param dataset  the dataset (<code>null</code> not permitted).
     * @param series  the series index.
     * @param x  the x-value.
     *
     * @return The indices of the two items that span the x-value.
     *
     * @since 1.0.16
     * 
     * @see #findYValue(org.jfree.data.xy.XYDataset, int, double) 
     */
    public static int[] findItemIndicesForX(XYDataset dataset, int series,
            double x) {
        ParamChecks.nullNotPermitted(dataset, "dataset");
        int itemCount = dataset.getItemCount(series);
        if (itemCount == 0) {
            return new int[] {-1, -1};
        }
        if (itemCount == 1) {
            if (x == dataset.getXValue(series, 0)) {
                return new int[] {0, 0};
            } else {
                return new int[] {-1, -1};
            }
        }
        if (dataset.getDomainOrder() == DomainOrder.ASCENDING) {
            int low = 0;
            int high = itemCount - 1;
            double lowValue = dataset.getXValue(series, low);
            if (lowValue > x) {
                return new int[] {-1, -1};
            }
            if (lowValue == x) {
                return new int[] {low, low};
            }
            double highValue = dataset.getXValue(series, high);
            if (highValue < x) {
                return new int[] {-1, -1};
            }
            if (highValue == x) {
                return new int[] {high, high};
            }
            int mid = (low + high) / 2;
            while (high - low > 1) {
                double midV = dataset.getXValue(series, mid);
                if (x == midV) {
                    return new int[] {mid, mid};
                }
                if (midV < x) {
                    low = mid;
                }
                else {
                    high = mid;
                }
                mid = (low + high) / 2;
            }
            return new int[] {low, high};
        }
        else if (dataset.getDomainOrder() == DomainOrder.DESCENDING) {
            int high = 0;
            int low = itemCount - 1;
            double lowValue = dataset.getXValue(series, low);
            if (lowValue > x) {
                return new int[] {-1, -1};
            }
            double highValue = dataset.getXValue(series, high);
            if (highValue < x) {
                return new int[] {-1, -1};
            }
            int mid = (low + high) / 2;
            while (high - low > 1) {
                double midV = dataset.getXValue(series, mid);
                if (x == midV) {
                    return new int[] {mid, mid};
                }
                if (midV < x) {
                    low = mid;
                }
                else {
                    high = mid;
                }
                mid = (low + high) / 2;
            }
            return new int[] {low, high};
        }
        else {
            // we don't know anything about the ordering of the x-values,
            // so we iterate until we find the first crossing of x (if any)
            // we know there are at least 2 items in the series at this point
            double prev = dataset.getXValue(series, 0);
            if (x == prev) {
                return new int[] {0, 0}; // exact match on first item
            }
            for (int i = 1; i < itemCount; i++) {
                double next = dataset.getXValue(series, i);
                if (x == next) {
                    return new int[] {i, i}; // exact match
                }
                if ((x > prev && x < next) || (x < prev && x > next)) {
                    return new int[] {i - 1, i}; // spanning match
                }
            }
            return new int[] {-1, -1}; // no crossing of x
        }
    }

}
