ByteEdit/src/org/fife/ui/autocomplete/DelegatingCellRenderer.java

/*
 * 12/22/2008
 * DelegatingCellRenderer.java - A renderer for Completions that will delegate
 * to the Completion's provider's renderer, if there is one.
 * This library is distributed under a modified BSD license. See the included
 * AutoComplete.License.txt file for details.
 */
package org.fife.ui.autocomplete;

import java.awt.Component;

import javax.swing.DefaultListCellRenderer;
import javax.swing.JComponent;
import javax.swing.JList;
import javax.swing.ListCellRenderer;

/**
 * List cell renderer that delegates to a {@link CompletionProvider}'s renderer,
 * if it has one. If it doesn't, it calls into a fallback renderer. If a
 * fallback renderer isn't specified, it simply renders
 * <code>(({@link Completion})value).toString()</code>.
 *
 * @author Robert Futrell
 * @version 1.0
 */
class DelegatingCellRenderer extends DefaultListCellRenderer {

	/**
	 * The renderer to fall back on if one isn't specified by a provider. This is
	 * usually <tt>this</tt>.
	 */
	private ListCellRenderer fallback;

	/**
	 * Returns the fallback cell renderer.
	 *
	 * @return The fallback cell renderer.
	 * @see #setFallbackCellRenderer(ListCellRenderer)
	 */
	public ListCellRenderer getFallbackCellRenderer() {
		return fallback;
	}

	/**
	 * {@inheritDoc}
	 */
	@Override
	public Component getListCellRendererComponent(JList list, Object value, int index, boolean selected,
			boolean hasFocus) {
		Completion c = (Completion) value;
		CompletionProvider p = c.getProvider();
		ListCellRenderer r = p.getListCellRenderer();
		if (r != null) {
			return r.getListCellRendererComponent(list, value, index, selected, hasFocus);
		}
		if (fallback == null) {
			return super.getListCellRendererComponent(list, value, index, selected, hasFocus);
		}
		return fallback.getListCellRendererComponent(list, value, index, selected, hasFocus);
	}

	/**
	 * Sets the fallback cell renderer.
	 *
	 * @param fallback The fallback cell renderer. If this is <code>null</code>,
	 *                 <tt>this</tt> will be used.
	 * @see #getFallbackCellRenderer()
	 */
	public void setFallbackCellRenderer(ListCellRenderer fallback) {
		this.fallback = fallback;
	}

	/**
	 * {@inheritDoc}
	 */
	@Override
	public void updateUI() {
		super.updateUI();
		if ((fallback instanceof JComponent) && fallback != this) {
			((JComponent) fallback).updateUI();
		}
	}
}