/*
 * @(#)ExampleFileFilter.java	1.16 04/07/26
 * 
 * Copyright (c) 2004 Sun Microsystems, Inc. All Rights Reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * 
 * -Redistribution of source code must retain the above copyright notice, this
 *  list of conditions and the following disclaimer.
 * 
 * -Redistribution in binary form must reproduce the above copyright notice, 
 *  this list of conditions and the following disclaimer in the documentation
 *  and/or other materials provided with the distribution.
 * 
 * Neither the name of Sun Microsystems, Inc. or the names of contributors may 
 * be used to endorse or promote products derived from this software without 
 * specific prior written permission.
 * 
 * This software is provided "AS IS," without a warranty of any kind. ALL 
 * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING
 * ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE
 * OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN MIDROSYSTEMS, INC. ("SUN")
 * AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE
 * AS A RESULT OF USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS
 * DERIVATIVES. IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE FOR ANY LOST 
 * REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL, 
 * INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY 
 * OF LIABILITY, ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE, 
 * EVEN IF SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
 * 
 * You acknowledge that this software is not designed, licensed or intended
 * for use in the design, construction, operation or maintenance of any
 * nuclear facility.
 */

/*
 * @(#)ExampleFileFilter.java	1.16 04/07/26
 */
package org.jalgo.module.kmp.algorithm;

import java.io.File;
import java.util.Hashtable;
import java.util.Enumeration;
import javax.swing.filechooser.FileFilter;

/**
 * A convenience implementation of FileFilter that filters out
 * all files except for those type extensions that it knows about.
 *
 * Extensions are of the type ".foo", which is typically found on
 * Windows and Unix boxes, but not on Macinthosh. Case is ignored.
 *
 * Example - create a new filter that filerts out all files
 * but gif and jpg image files:
 *
 *     JFileChooser chooser = new JFileChooser();
 *     ExampleFileFilter filter = new ExampleFileFilter(
 *                   new String{"gif", "jpg"}, "JPEG & GIF Images")
 *     chooser.addChoosableFileFilter(filter);
 *     chooser.showOpenDialog(this);
 *
 * @version 1.16 07/26/04
 * @author Jeff Dinkins, redesign by Danilo Lisske
 */
public class ExampleFileFilter extends FileFilter {
    private Hashtable filters = null;
    private String description = null;
    private String fullDescription = null;
    private boolean useExtensionsInDescription = true;

    /**
     * Creates a file filter. If no filters are added, then all
     * files are accepted.
     *
     * @see #addExtension
     */
    public ExampleFileFilter() {
    	this.filters = new Hashtable();
    }

    /**
     * Creates a file filter that accepts files with the given extension.
     * Example: new ExampleFileFilter("jpg");
     *
     * @see #addExtension
     * @param extension the extension
     */
    public ExampleFileFilter(String extension) {
    	this(extension,null);
    }

    /**
     * Creates a file filter that accepts the given file type.
     * Example: new ExampleFileFilter("jpg", "JPEG Image Images");
     *
     * Note that the "." before the extension is not needed. If
     * provided, it will be ignored.
     *
     * @see #addExtension
     * @param extension the extension
     * @param description the description
     */
    public ExampleFileFilter(String extension, String description) {
    	this();
    	if(extension!=null) addExtension(extension);
    	if(description!=null) setDescription(description);
    }

    /**
     * Creates a file filter from the given string array.
     * Example: new ExampleFileFilter(String {"gif", "jpg"});
     *
     * Note that the "." before the extension is not needed adn
     * will be ignored.
     *
     * @see #addExtension
     * @param filters the filters
     */
    public ExampleFileFilter(String[] filters) {
    	this(filters, null);
    }

    /**
     * Creates a file filter from the given string array and description.
     * Example: new ExampleFileFilter(String {"gif", "jpg"}, "Gif and JPG Images");
     *
     * Note that the "." before the extension is not needed and will be ignored.
     *
     * @see #addExtension
     * @param filters the filters
     * @param description the description
     */
    public ExampleFileFilter(String[] filters, String description) {
    	this();
    	for (int i = 0; i < filters.length; i++) {
    		// add filters one by one
    		addExtension(filters[i]);
    	}
    	if (description != null) setDescription(description);
    }

    /**
     * Return true if this file should be shown in the directory pane,
     * false if it shouldn't.
     *
     * Files that begin with "." are ignored.
     *
     * @see #getExtension
     */
    public boolean accept(File f) {
		if(f != null) {
		    if(f.isDirectory()) {
			return true;
		    }
		    String extension = getExtension(f);
		    if(extension != null && filters.get(getExtension(f)) != null) {
			return true;
		    };
		}
		return false;
    }

    /**
     * Return the extension portion of the file's name .
     *
     * @see #getExtension
     * @see FileFilter#accept
     * @param f the file
     * @return the extension
     */
    public String getExtension(File f) {
		if(f != null) {
		    String filename = f.getName();
		    int i = filename.lastIndexOf('.');
		    if(i>0 && i<filename.length()-1) {
			return filename.substring(i+1).toLowerCase();
		    };
		}
		return null;
    }

    /**
     * Adds a filetype "dot" extension to filter against.
     *
     * For example: the following code will create a filter that filters
     * out all files except those that end in ".jpg" and ".tif":
     *
     *   ExampleFileFilter filter = new ExampleFileFilter();
     *   filter.addExtension("jpg");
     *   filter.addExtension("tif");
     *
     * Note that the "." before the extension is not needed and will be ignored.
     * 
     * @param extension the extension
     */
    public void addExtension(String extension) {
		if(filters == null) {
		    filters = new Hashtable(5);
		}
		filters.put(extension.toLowerCase(), this);
		fullDescription = null;
    }


    /**
     * Returns the human readable description of this filter. For
     * example: "JPEG and GIF Image Files (*.jpg, *.gif)"
     *
     * @see FileFilter#getDescription
     */
    public String getDescription() {
		if(fullDescription == null) {
		    if(description == null || isExtensionListInDescription()) {
	 		fullDescription = description==null ? "(" : description + " (";
			// build the description from the extension list
			Enumeration extensions = filters.keys();
			if(extensions != null) {
			    fullDescription += "." + (String) extensions.nextElement();
			    while (extensions.hasMoreElements()) {
				fullDescription += ", ." + (String) extensions.nextElement();
			    }
			}
			fullDescription += ")";
		    } else {
			fullDescription = description;
		    }
		}
		return fullDescription;
    }

    /**
     * Sets the human readable description of this filter. For
     * example: filter.setDescription("Gif and JPG Images");
     *
     * @param description the description
     */
    public void setDescription(String description) {
		this.description = description;
		fullDescription = null;
    }

    /**
     * Determines whether the extension list (.jpg, .gif, etc) should
     * show up in the human readable description.
     *
     * Only relevent if a description was provided in the constructor
     * or using setDescription();
     *
     * @param b the value
     */
    public void setExtensionListInDescription(boolean b) {
		useExtensionsInDescription = b;
		fullDescription = null;
    }

    /**
     * Returns whether the extension list (.jpg, .gif, etc) should
     * show up in the human readable description.
     *
     * Only relevent if a description was provided in the constructor
     * or using setDescription();
     *
     * @return the value
     */
    public boolean isExtensionListInDescription() {
    	return useExtensionsInDescription;
    }
}
