code: public void updateAttrValue(final AttrName _attrName,
                                  final String _value,
                                  final String _updateValue)
      {
          synchronized (this.attrUpdated) {
              synchronized (this.attrValues) {
                  this.attrValues.put(_attrName, _value);
              }
              this.attrUpdated.put(_attrName, _updateValue);
          }
      }
docs: Updates a value for an attribute in the cache and marks then as modified.
  Only after calling method {@link #commitAttrValuesInDB} the updated
  attribute value is stored in the database!
  
  @param _attrName name of attribute to update
  @param _value new value to set directly
  @param _updateValue new value to be set in the database
  @see #attrUpdated
  @see #attrValues