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/**
 * 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.apache.heron.spi.statemgr;

/**
 * A callback interface used to set a watch on any of the nodes
 * in certain implemenations of IStateManager (Zookeeper for example)
 * Any event on that node will trigger the callback (processWatch).
 */
public interface WatchCallback {

  /**
   * When watch is triggered, process it
   *
   * @param path the node path
   * @param eventType the WatchEventType
   */
  void processWatch(String path, WatchEventType eventType);

  enum WatchEventType {
    None,
    NodeCreated,
    NodeDeleted,
    NodeDataChanged,
    NodeChildrenChanged;
  }
}