zookeeper-api/src/main/java/org/apache/helix/zookeeper/zkclient/DataUpdater.java

/**
 * Copyright 2010 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 org.apache.helix.zookeeper.zkclient;

/**
 * Updates the data of a znode. This is used together with {@link ZkClient#updateDataSerialized(String, DataUpdater)}.
 *
 * @param <T>
 */
public interface DataUpdater<T extends Object> {

    /**
     * Updates the current data of a znode.
     *
     * @param currentData
     *            The current contents.
     * @return the new data that should be written back to ZooKeeper.
     */
    public T update(T currentData);

}