structuredviewer.java

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/*******************************************************************************
 * Copyright (c) 2000, 2006 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.jface.viewers;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;

import org.eclipse.core.runtime.ListenerList;
import org.eclipse.jface.util.Assert;
import org.eclipse.jface.util.IOpenEventListener;
import org.eclipse.jface.util.OpenStrategy;
import org.eclipse.jface.util.SafeRunnable;
import org.eclipse.swt.custom.TableTreeItem;
import org.eclipse.swt.dnd.DragSource;
import org.eclipse.swt.dnd.DragSourceListener;
import org.eclipse.swt.dnd.DropTarget;
import org.eclipse.swt.dnd.DropTargetListener;
import org.eclipse.swt.dnd.Transfer;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.events.SelectionListener;
import org.eclipse.swt.graphics.Color;
import org.eclipse.swt.graphics.Font;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Item;
import org.eclipse.swt.widgets.TableItem;
import org.eclipse.swt.widgets.TreeItem;
import org.eclipse.swt.widgets.Widget;

/**
 * Abstract base implementation for structure-oriented viewers (trees, lists,
 * tables). Supports custom sorting, filtering, and rendering.
 * <p>
 * Any number of viewer filters can be added to this viewer (using
 * <code>addFilter</code>). When the viewer receives an update, it asks each
 * of its filters if it is out of date, and refilters elements as required.
 * </p>
 * 
 * @see ViewerFilter
 * @see ViewerSorter
 * @see ViewerComparator
 */
public abstract class StructuredViewer extends ContentViewer implements IPostSelectionProvider {

	/**
	 * A map from the viewer's model elements to SWT widgets. (key type:
	 * <code>Object</code>, value type: <code>Widget</code>, or <code>Widget[]</code>).
	 * <code>null</code> means that the element map is disabled.
	 */
	private CustomHashtable elementMap;

	/**
	 * The comparer to use for comparing elements, or <code>null</code> to use
	 * the default <code>equals</code> and <code>hashCode</code> methods on
	 * the element itself.
	 */
	private IElementComparer comparer;

	/**
	 * This viewer's comparator used for sorting. <code>null</code> means there is no comparator.
	 */
	private ViewerComparator sorter;

	/**
	 * This viewer's filters (element type: <code>ViewerFilter</code>).
	 * <code>null</code> means there are no filters.
	 */
	private List filters;

	/**
	 * Indicates whether a selection change is in progress on this viewer.
	 * 
	 * @see #setSelection(ISelection, boolean)
	 */
	private boolean inChange;

	/**
	 * Used while a selection change is in progress on this viewer to indicates
	 * whether the selection should be restored.
	 * 
	 * @see #setSelection(ISelection, boolean)
	 */
	private boolean restoreSelection;

	/**
	 * List of double-click state listeners (element type:
	 * <code>IDoubleClickListener</code>).
	 * 
	 * @see #fireDoubleClick
	 */
	private ListenerList doubleClickListeners = new ListenerList();

	/**
	 * List of open listeners (element type:
	 * <code>ISelectionActivateListener</code>).
	 * 
	 * @see #fireOpen
	 */
	private ListenerList openListeners = new ListenerList();

	/**
	 * List of post selection listeners (element type:
	 * <code>ISelectionActivateListener</code>).
	 * 
	 * @see #firePostSelectionChanged
	 */
	private ListenerList postSelectionChangedListeners = new ListenerList();

	/**
	 * The colorAndFontCollector is an object used by viewers that
	 * support the IColorProvider, the IFontProvider and/or the 
	 * IViewerLabelProvider for color and font updates.
	 * Initialize it to have no color or font providing
	 * initially.
	 * @since 3.1
	 */
	private ColorAndFontCollector colorAndFontCollector = new ColorAndFontCollector();
	
	/**
	 * Empty array of widgets.
	 */
	private static Widget[] NO_WIDGETS = new Widget[0];

	/**
	 * The ColorAndFontCollector is a helper class for viewers
	 * that have color and font support ad optionally decorators.
	 * @see IColorDecorator
	 * @see IFontDecorator
	 * @see IColorProvider
	 * @see IFontProvider
	 * @see IDecoration
	 */
	protected class ColorAndFontCollectorWithProviders extends ColorAndFontCollector{

		IColorProvider colorProvider;

		IFontProvider fontProvider;
		
		/**
		 * Create a new instance of the receiver using the supplied
		 * label provider. If it is an IColorProvider or IFontProvider
		 * set these values up.
		 * @param provider IBaseLabelProvider
		 * @see IColorProvider
		 * @see IFontProvider
		 */
		public ColorAndFontCollectorWithProviders(IBaseLabelProvider provider) {
			super();
			if (provider instanceof IColorProvider) {
				colorProvider = (IColorProvider) provider;
			}
			if (provider instanceof IFontProvider) {
				fontProvider = (IFontProvider) provider;
			}
		}
		
	
		/* (non-Javadoc)
		 * @see org.eclipse.jface.viewers.StructuredViewer.ColorAndFontManager#setFontsAndColors(java.lang.Object)
		 */
		public void setFontsAndColors(Object element){
			
			if(fontProvider != null){
				if(font == null) {
					font = fontProvider.getFont(element);
				}	
			}
			
			if(colorProvider == null) {
				return;
			}			
			//Set the colors if they are not set yet
			if(background == null) {
				background = colorProvider.getBackground(element);
			}
			
			if(foreground == null) {
				foreground = colorProvider.getForeground(element);
			}			
		}
		
		/**
		 * Apply the fonts and colors to the control if
		 * required.
		 * @param control
		 */
		public void applyFontsAndColors(TableItem control) {
			
			if(colorProvider == null){
				if(usedDecorators){
					//If there is no provider only apply set values
					if(background != null) {
						control.setBackground(background);
					}
				
					if(foreground != null) {
						control.setForeground(foreground);
					}
				}
			}
			else{
				//Always set the value if there is a provider
				control.setBackground(background);
				control.setForeground(foreground);
			}
			
			if(fontProvider == null){
				if(usedDecorators && font != null) {
					control.setFont(font);
				}
			} else {
				control.setFont(font);
			}
			
			clear();
		}
		

	
		/* (non-Javadoc)
		 * @see org.eclipse.jface.viewers.StructuredViewer.ColorAndFontManager#applyFontsAndColors(org.eclipse.swt.widgets.TreeItem)
		 */
		public void applyFontsAndColors(TreeItem control) {
			
			if(colorProvider == null){
				if(usedDecorators){
					//If there is no provider only apply set values
					if(background != null) {
						control.setBackground(background);
					}
				
					if(foreground != null) {
						control.setForeground(foreground);
					}
				}
			}
			else{
				//Always set the value if there is a provider
				control.setBackground(background);
				control.setForeground(foreground);
			}
			
			if(fontProvider == null){
				if(usedDecorators && font != null) {
					control.setFont(font);
				}
			} else {
				control.setFont(font);
			}
			
			clear();
		}
		
	
		/* (non-Javadoc)
		 * @see org.eclipse.jface.viewers.StructuredViewer.ColorAndFontManager#applyFontsAndColors(org.eclipse.swt.custom.TableTreeItem)
		 */
		public void applyFontsAndColors(TableTreeItem control) {
			
			if(colorProvider == null){
				if(usedDecorators){
					//If there is no provider only apply set values
					if(background != null) {
						control.setBackground(background);
					}
				
					if(foreground != null) {
						control.setForeground(foreground);
					}
				}
			}
			else{
				//Always set the value if there is a provider
				control.setBackground(background);
				control.setForeground(foreground);
			}
			
			if(fontProvider == null){
				if(usedDecorators && font != null) {
					control.setFont(font);
				}
			} else {
				control.setFont(font);
			}
			
			clear();
		}
		
		
	}
	
	/**
	 * The ColorAndFontManager collects fonts and colors without a
	 * a color or font provider.
	 *
	 */
	protected class ColorAndFontCollector {

		Color foreground = null;

		Color background = null;

		Font font = null;

		boolean usedDecorators = false;

		/**
		 * Create a new instance of the receiver with
		 * no colour and font provider.	
		 */
		public ColorAndFontCollector(){
			super();
		}
		

		/**
		 * Clear all of the results.
		 */
		public void clear() {
			foreground = null;
			background = null;
			font = null;
			usedDecorators = false;
		}

		
		/**
		 * Set the initial fonts and colors for the element from the
		 * content providers.
		 * @param element Object
		 */
		public void setFontsAndColors(Object element){
			//Do nothing if there are no providers
		}

		/**
		 * Set that decorators were applied.
		 */
		public void setUsedDecorators() {
			this.usedDecorators = true;
		}

		/**
		 * Apply the fonts and colors to the control if
		 * required.
		 * @param control
		 */
		public void applyFontsAndColors(TableItem control) {
			
			if(usedDecorators){
				//If there is no provider only apply set values
				if(background != null) {
					control.setBackground(background);
				}
			
				if(foreground != null) {
					control.setForeground(foreground);
				}
		
				if(font != null) {
					control.setFont(font);
				}
			}
			clear();
		}
		
		/**
		 * Apply the fonts and colors to the control if
		 * required.
		 * @param control
		 */
		public void applyFontsAndColors(TreeItem control) {
			if(usedDecorators){
				//If there is no provider only apply set values
				if(background != null) {
					control.setBackground(background);
				}
			
				if(foreground != null) {
					control.setForeground(foreground);
				}
		
				if(font != null) {
					control.setFont(font);
				}
			}
			clear();
		}
		
		/**
		 * Apply the fonts and colors to the control if
		 * required.
		 * @param control
		 */
		public void applyFontsAndColors(TableTreeItem control) {
			if(usedDecorators){
				//If there is no provider only apply set values
				if(background != null) {
					control.setBackground(background);
				}
			
				if(foreground != null) {
					control.setForeground(foreground);
				}
		
				if(font != null) {
					control.setFont(font);
				}
			}
			clear();
		}
		
		/**
		 * Set the background color.