IZkDataListener.java

/**
 * Copyright 2008 the original author or authors.
 *
 * 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 net.sf.katta.zk;

/**
 * An {@link IZkDataListener} can be registered at a {@link ZKClient} for
 * listening on zk data changes for a given path.
 * 
 * Node: Also this listener re-subscribes it watch for the path on each zk event
 * (zk watches are one-timers) is is not guaranteed that events on the path are
 * missing (see http://zookeeper.wiki.sourceforge.net/ZooKeeperWatches). An
 * implementation of this class should take that into account.
 */
import net.sf.katta.util.KattaException;

import org.apache.hadoop.io.Writable;

public interface IZkDataListener<W extends Writable> {

  void handleDataChange(String dataPath, W data) throws KattaException;

  void handleDataAdded(String dataPath, W data) throws KattaException;

  void handleDataDeleted(String dataPath) throws KattaException;

  W createWritable();
}