/**
 * All rights reserved. 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 org.jivesoftware.smackx.provider;

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

import org.jivesoftware.smack.packet.PacketExtension;
import org.jivesoftware.smack.provider.PacketExtensionProvider;
import org.jivesoftware.smack.util.PacketParserUtils;
import org.jivesoftware.smackx.pubsub.provider.ItemProvider;
import org.jivesoftware.smackx.pubsub.provider.ItemsProvider;
import org.xmlpull.v1.XmlPullParser;

/**
 * 
 * This class simplifies parsing of embedded elements by using the <a
 * href="http://en.wikipedia.org/wiki/Template_method_pattern">Template Method
 * Pattern</a>. After extracting the current element attributes and content of
 * any child elements, the template method (
 * {@link #createReturnExtension(String, String, Map, List)} is called.
 * Subclasses then override this method to create the specific return type.
 * 
 * <p>
 * To use this class, you simply register your subclasses as extension providers
 * in the <b>smack.properties</b> file. Then they will be automatically picked
 * up and used to parse any child elements.
 * 
 * <pre>
 * For example, given the following message
 * 
 * <message from='pubsub.shakespeare.lit' to='francisco@denmark.lit' id='foo>
 *    <event xmlns='http://jabber.org/protocol/pubsub#event>
 *       <items node='princely_musings'>
 *          <item id='asdjkwei3i34234n356'>
 *             <entry xmlns='http://www.w3.org/2005/Atom'>
 *                <title>Soliloquy</title>
 *                <link rel='alternative' type='text/html'/>
 *                <id>tag:denmark.lit,2003:entry-32397</id>
 *             </entry>
 *          </item>
 *       </items>
 *    </event>
 * </message>
 * 
 * I would have a classes
 * {@link ItemsProvider} extends {@link EmbeddedExtensionProvider}
 * {@link ItemProvider} extends {@link EmbeddedExtensionProvider}
 * and
 * AtomProvider extends {@link PacketExtensionProvider}
 * 
 * These classes are then registered in the meta-inf/smack.providers file
 * as follows.
 * 
 *   <extensionProvider>
 *      <elementName>items</elementName>
 *      <namespace>http://jabber.org/protocol/pubsub#event</namespace>
 *      <className>org.jivesoftware.smackx.provider.ItemsEventProvider</className>
 *   </extensionProvider>
 *   <extensionProvider>
 *       <elementName>item</elementName>
 *       <namespace>http://jabber.org/protocol/pubsub#event</namespace>
 *       <className>org.jivesoftware.smackx.provider.ItemProvider</className>
 *   </extensionProvider>
 * 
 * </pre>
 * 
 * @author Robin Collier
 * 
 * @deprecated This has been moved to
 *             {@link org.jivesoftware.smack.provider.EmbeddedExtensionProvider}
 */
@Deprecated
abstract public class EmbeddedExtensionProvider implements
		PacketExtensionProvider {

	abstract protected PacketExtension createReturnExtension(
			String currentElement, String currentNamespace,
			Map<String, String> attributeMap,
			List<? extends PacketExtension> content);

	@Override
	final public PacketExtension parseExtension(XmlPullParser parser)
			throws Exception {
		final String namespace = parser.getNamespace();
		final String name = parser.getName();
		final Map<String, String> attMap = new HashMap<String, String>();

		for (int i = 0; i < parser.getAttributeCount(); i++) {
			attMap.put(parser.getAttributeName(i), parser.getAttributeValue(i));
		}
		final List<PacketExtension> extensions = new ArrayList<PacketExtension>();

		do {
			final int tag = parser.next();

			if (tag == XmlPullParser.START_TAG) {
				extensions.add(PacketParserUtils.parsePacketExtension(
						parser.getName(), parser.getNamespace(), parser));
			}
		} while (!name.equals(parser.getName()));

		return createReturnExtension(name, namespace, attMap, extensions);
	}
}