/*******************************************************************************
 * Copyright (c) 2001, 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.ui.internal.views.properties.tabbed.view;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.eclipse.ui.views.properties.tabbed.ITabbedPropertySheetPageContributor;


/**
 * tabbed property registry factory. Caches the tabbed property registry
 * by tabbed property contributor ID. 
 * 
 * @author Anthony Hunter
 */
public class TabbedPropertyRegistryFactory {

	class CacheData {
		TabbedPropertyRegistry registry;
		List references;
	}

	/**
	 * singleton instance of this class
	 */
	private static TabbedPropertyRegistryFactory INSTANCE =
		new TabbedPropertyRegistryFactory();

	/**
	 * get the singleton instance of this class
	 */
	public static TabbedPropertyRegistryFactory getInstance() {
		return INSTANCE;
	}

	/**
	 * private constructor.
	 */
	private TabbedPropertyRegistryFactory() {
		super();
		idToCacheData = new HashMap();
	}

	protected Map idToCacheData; // cache

	/** 
	 * Creates a registry for the given contributor.
	 */
	public TabbedPropertyRegistry createRegistry(ITabbedPropertySheetPageContributor target) {
		/**
		 * Get the contributor id from the ITabbedPropertySheetPageContributor interface
		 */
		String key = target.getContributorId();
		CacheData data = (CacheData) idToCacheData.get(key);
		if (data == null) {
			data = new CacheData();
			data.registry =
				new TabbedPropertyRegistry(key);
			data.references = new ArrayList(5);
			idToCacheData.put(key, data);
		}
		data.references.add(target);
		// keeps track of contributor using the same registry
		return data.registry;
	}

	/** 
	 * Indicates that the given contributor no longer needs
	 * a registry. The registry will be disposed when
	 * no other contributor of the same type needs it.
	 */
	public void disposeRegistry(ITabbedPropertySheetPageContributor target) {
		/**
		 * Get the contributor id from the ITabbedPropertySheetPageContributor interface
		 */
		String key = target.getContributorId();
		CacheData data = (CacheData) idToCacheData.get(key);
		data.references.remove(target);
		if (data.references.isEmpty()) {
			idToCacheData.remove(key);
		}
	}
}
