trunk/simple/src/main/java/org/odftoolkit/simple/Component.java

/* 
Licensed to the Apache Software Foundation (ASF) under one
or more contributor license agreements.  See the NOTICE file
distributed with this work for additional information
regarding copyright ownership.  The ASF licenses this file
to you 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 org.odftoolkit.simple;

import java.util.IdentityHashMap;

import org.odftoolkit.odfdom.pkg.OdfElement;
import org.odftoolkit.odfdom.pkg.OdfFileDom;

/**
 * This class is the parent of classes that present all kinds of document
 * structures.
 * 
 * @since 0.5
 */
public abstract class Component {

	/**
	 * Return the instance of OdfElement which presents this structure.
	 * 
	 * @return the instance of OdfElement
	 */
	public abstract OdfElement getOdfElement();

	/**
	 * Register component to the map repository
	 * 
	 * @param component
	 *            the component to be registered.
	 * @param element
	 *            the instance of OdfElement which presents this component.
	 * @see Document#getComponentMap()
	 */
	protected static void registerComponent(Component component, OdfElement element) {
		Document ownerDoc = component.getOwnerDocument();
		synchronized (ownerDoc) {
			IdentityHashMap<OdfElement, Component> repository = ownerDoc.getComponentMap();
			repository.put(element, component);
		}
	}
	
	/**
	 * Unregister component from the map repository
	 * 
	 * @param element
	 *            the instance of OdfElement which presents this component.
	 * 
	 * @see Document#getComponentMap()
	 * @since 0.6.5
	 */
	protected static void unregisterComponent(OdfElement element) {
		Document ownerDoc = (Document) ((OdfFileDom) element.getOwnerDocument()).getDocument();
		synchronized (ownerDoc) {
			IdentityHashMap<OdfElement, Component> repository = ownerDoc.getComponentMap();
			repository.remove(element);
		}
	}

	/**
	 * Get the component instance by the element instance. Return null if there
	 * is no such element registered.
	 * 
	 * @param element
	 *            the instance of OdfElement which presents this component.
	 * @return the component instance
	 */
	protected static Component getComponentByElement(OdfElement element) {
		Document doc = (Document) ((OdfFileDom) element.getOwnerDocument()).getDocument();
		IdentityHashMap<OdfElement, Component> repository = doc.getComponentMap();
		return repository.get(element);
	}

	/**
	 * Get the owner document of this component
	 * 
	 * @return - the owner document
	 */
	public Document getOwnerDocument() {
		return (Document) ((OdfFileDom) getOdfElement().getOwnerDocument()).getDocument();
	}

}