/*
 * GNU LESSER GENERAL PUBLIC LICENSE Copyright (C) 2006 The Lobo Project
 * 
 * This library is free software; you can redistribute it and/or modify it under
 * the terms of the GNU Lesser General Public License as published by the Free
 * Software Foundation; either version 2.1 of the License, or (at your option)
 * any later version.
 * 
 * This library is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
 * details.
 * 
 * You should have received a copy of the GNU Lesser General Public License
 * along with this library; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 * 
 * Contact info: xamjadmin@users.sourceforge.net
 */
/*
 * Created on Oct 8, 2005
 */
package com.nvarghese.beowulf.common.cobra.html.domimpl;

import java.util.Map;

import org.w3c.dom.Node;
import org.w3c.dom.html2.HTMLCollection;

import com.nvarghese.beowulf.common.cobra.js.AbstractScriptableDelegate;

public class FilteredHTMLCollectionImpl extends AbstractScriptableDelegate implements HTMLCollection {

	private class CounterNodeVisitor implements NodeVisitor {

		private int counter = 0;

		public int getCount() {

			return counter;
		}

		public void visit(Node node) {

			if (filter.accept(node)) {
				counter++;
			}
		}
	}

	private final NodeFilter filter;
	private final Object lock;
	private final NodeImpl rootNode;

	// Note: Class must be public for reflection to work.
	// OPTIMIZE: Indexers are inefficient in this class.
	private final Map sourceMap;

	public FilteredHTMLCollectionImpl(NodeImpl rootNode, Map sourceMap, NodeFilter filter, Object lock) {

		this.sourceMap = sourceMap;
		this.filter = filter;
		this.lock = lock;
		this.rootNode = rootNode;
	}

	public int getLength() {

		CounterNodeVisitor visitor = new CounterNodeVisitor();
		synchronized (lock) {
			rootNode.visitImpl(visitor);
			return visitor.getCount();
		}
	}

	public Node item(final int index) {

		NodeVisitor visitor = new NodeVisitor() {

			private int counter = 0;

			public void visit(Node node) {

				if (filter.accept(node)) {
					if (counter == index) {
						throw new StopVisitorException(node);
					}
					counter++;
				}
			}
		};
		synchronized (lock) {
			try {
				rootNode.visitImpl(visitor);
				return null;
			} catch (StopVisitorException sve) {
				return (Node) sve.getTag();
			}
		}
	}

	public Node namedItem(String name) {

		synchronized (lock) {
			Node node = (Node) sourceMap.get(name);
			if ((node != null) && filter.accept(node)) {
				return node;
			}
			return null;
		}
	}
}