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/*
 * Copyright © 1996-2009 GlobalMentor, Inc. 
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.globalmentor.swing.tree;

import java.awt.Component;
import java.util.*;
import javax.swing.*;
import javax.swing.tree.*;

/**
 * A tree cell renderer that can render different icons and strings for various types of user objects. If the a tree node is an {@link IconTreeNode} that has an
 * icon, its icon is used. If not, specified icons are used for the specified types of user objects if a tree node is a {@link DefaultMutableTreeNode};
 * otherwise, the default icons are used from the parent class. //TODO fix to get strings just like we get icons: Specified strings are constructed from
 * @author Garret Wilson
 */
public class UserObjectTreeCellRenderer extends DefaultTreeCellRenderer {

	/** The map used to hold the open icons, keyed to user object classes. */
	private final Map openIconMap = new HashMap();

	/**
	 * Retrieves the open icon for a user object of the indicated key.
	 * @param userObjectKey The key of the user object.
	 * @return The icon to use for the user object, or null if no open icon is registered for this user object type.
	 */
	public Icon getOpenIcon(final Object userObjectKey) {
		return openIconMap.get(userObjectKey); //return whatever icon we find for this user object key
	}

	/**
	 * Registers an open icon to be used with a particular user object.
	 * @param userObjectKey The key of the user object.
	 * @param icon The icon to register with the user object, or null if no icon should be associated with the user object.
	 */
	protected void registerOpenIcon(final Object userObjectKey, final Icon icon) {
		openIconMap.put(userObjectKey, icon); //put the icon in the map
	}

	/**
	 * Registers an open icon to be used with a particular user object.
	 * @param userObjectClass The class of the user object.
	 * @param icon The icon to register with the user object, or null if no icon should be associated with the user object.
	 */
	public void registerOpenIcon(final Class userObjectClass, final Icon icon) {
		openIconMap.put(userObjectClass, icon); //put the icon in the map, keyed to the class of the user object
	}

	/** The map used to hold the closed icons, keyed to user object classes. */
	private final Map closedIconMap = new HashMap();

	/**
	 * Retrieves the closed icon for a user object of the indicated key.
	 * @param userObjectKey The key of the user object.
	 * @return The icon to use for the user object, or null if no closed icon is registered for this user object type.
	 */
	public Icon getClosedIcon(final Object userObjectKey) {
		return closedIconMap.get(userObjectKey); //return whatever icon we find for this user object class
	}

	/**
	 * Registers a closed icon to be used with a particular user object.
	 * @param userObjectKey The key of the user object.
	 * @param icon The icon to register with the user object, or null if no icon should be associated with the user object.
	 */
	protected void registerClosedIcon(final Object userObjectKey, final Icon icon) {
		closedIconMap.put(userObjectKey, icon); //put the icon in the map
	}

	/**
	 * Registers a closed icon to be used with a particular user object.
	 * @param userObjectClass The class of the user object.
	 * @param icon The icon to register with the user object, or null if no icon should be associated with the user object.
	 */
	public void registerClosedIcon(final Class userObjectClass, final Icon icon) {
		closedIconMap.put(userObjectClass, icon); //put the icon in the map, keyed to the class of the user object
	}

	/** The map used to hold the leaf icons, keyed to user object classes. */
	private final Map leafIconMap = new HashMap();

	/**
	 * Retrieves the leaf icon for a user object of the indicated key.
	 * @param userObjectKey The class of the user object.
	 * @return The icon to use for the user object, or null if no leaf icon is registered for this user object type.
	 */
	public Icon getLeafIcon(final Object userObjectKey) {
		return leafIconMap.get(userObjectKey); //return whatever icon we find for this user object class
	}

	/**
	 * Registers a leaf icon to be used with a particular user object.
	 * @param userObjectKey The key of the user object.
	 * @param icon The icon to register with the user object, or null if no icon should be associated with the user object.
	 */
	protected void registerLeafIcon(final Object userObjectKey, final Icon icon) {
		leafIconMap.put(userObjectKey, icon); //put the icon in the map
	}

	/**
	 * Registers a leaf icon to be used with a particular user object.
	 * @param userObjectClass The class of the user object.
	 * @param icon The icon to register with the user object, or null if no icon should be associated with the user object.
	 */
	public void registerLeafIcon(final Class userObjectClass, final Icon icon) {
		leafIconMap.put(userObjectClass, icon); //put the icon in the map, keyed to the class of the user object
	}

	/** Default constructor. */
	public UserObjectTreeCellRenderer() {
		super(); //construct the parent object
	}

	/**
	 * Configures the renderer based on the passed in components. The component is configured using the defaults of the parent class, except for the icon. If the
	 * value is a {@link DefaultMutableTreeNode}, the user object is examined and any icon registered for the user item's class is used. Otherwise, the default
	 * icon (that configured by the parent class) is used. Note that this version only works properly with implementations of {@link DefaultTreeCellRenderer} that
	 * return an instance of {@link JLabel}.
	 * @param tree The tree component.
	 * @param value The value for which a renderer should be returned.
	 * @param isSelected Whether the value is selected.
	 * @param isExpanded Whether the value is expanded.
	 * @param isLeaf Whether the value is a leaf.
	 * @param row The row of the value in the tree.
	 * @param hasFocus Whether the value has the focus.
	 * @return The component to use for rendering.
	 * @see DefaultTreeCellRenderer#getTreeCellRendererComponent
	 */
	public Component getTreeCellRendererComponent(final JTree tree, final Object value, final boolean isSelected, final boolean isExpanded, final boolean isLeaf,
			final int row, final boolean hasFocus) {
		//get the default component to be used for rendering
		final Component component = super.getTreeCellRendererComponent(tree, value, isSelected, isExpanded, isLeaf, row, hasFocus);
		if(value instanceof DefaultMutableTreeNode) { //if the value is a DefaultMutableTreeNode, which stores user objects
			if(component instanceof JLabel) { //if the component is a label (as we expect from the default implementation of DefaultTreeCellRenderer)
				final JLabel label = (JLabel)component; //cast the component to a label
				final DefaultMutableTreeNode defaultMutableTreeNode = (DefaultMutableTreeNode)value; //cast the value to the type of node that will let us get the user object
				//get the key associated with the user object
				final Object userObjectKey = getUserObjectKey(defaultMutableTreeNode.getUserObject());
				Icon icon = null; //we'll try to assign a new icon here
				if(isLeaf) { //if this is a leaf node
					if(value instanceof IconTreeNode) { //if the tree node is an icon tree node
						icon = ((IconTreeNode)value).getLeafIcon(); //get the leaf icon
					}
					if(icon == null) { //if the tree node is not an icon tree node, or it didn't have an appropriate icon
						icon = getLeafIcon(userObjectKey); //get the leaf icon registered for this user object key
					}
				} else if(isExpanded) { //if this value is expanded
					if(value instanceof IconTreeNode) { //if the tree node is an icon tree node
						icon = ((IconTreeNode)value).getOpenIcon(); //get the open icon
					}
					if(icon == null) { //if the tree node is not an icon tree node, or it didn't have an appropriate icon
						icon = getOpenIcon(userObjectKey); //get the open icon registered for this user object key
					}
				} else { //if we shouldn't look for a leaf or open icon
					if(value instanceof IconTreeNode) { //if the tree node is an icon tree node
						icon = ((IconTreeNode)value).getClosedIcon(); //get the closed icon
					}
					if(icon == null) { //if the tree node is not an icon tree node, or it didn't have an appropriate icon
						icon = getClosedIcon(userObjectKey); //get the closed icon registered for this user object key
					}
				}
				if(icon != null) { //if we found a new icon to use
					if(tree.isEnabled()) //if the tree is enabled
						label.setIcon(icon); //set the enabled icon
					else
						//if the tree is not enabled
						label.setDisabledIcon(icon); //set the disabled icon
				}
			}
		}
		return component; //return the component, possibly with our modifications
	}

	/**
	 * Retrieves the key used to lookup data, such as icons, specific for this user object.
	 * 
	 * This version returns the class of the user object, but subclasses may override this method to return other keys. Such subclasses should also allow other
	 * ways of populating the icon map to allow for other keys.
	 * 
	 * @param userObject The user object for which a key should be returned.
	 * @return The key for looking up data for the user object, or null if no key could be determined for the user object or if the user object is
	 *         null.
	 * @see Object#getClass
	 */
	protected Object getUserObjectKey(final Object userObject) {
		return userObject != null ? userObject.getClass() : null; //return the class of the user object, if there is a valid user object
	}
}