heron/statemgrs/src/java/org/apache/heron/statemgr/zookeeper/ZkWatcherCallback.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.apache.heron.statemgr.zookeeper;

import org.apache.heron.spi.statemgr.WatchCallback;
import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;

public final class ZkWatcherCallback {
  public static Watcher makeZkWatcher(final WatchCallback watcher) {
    return watcher == null
        ? null
        : new Watcher() {
          @Override
          public void process(WatchedEvent watchedEvent) {
            WatchCallback.WatchEventType watchEventType;
            switch (watchedEvent.getType()) {
              case None:
                watchEventType = WatchCallback.WatchEventType.None;
                break;
              case NodeCreated:
                watchEventType = WatchCallback.WatchEventType.NodeCreated;
                break;
              case NodeDeleted:
                watchEventType = WatchCallback.WatchEventType.NodeDeleted;
                break;
              case NodeDataChanged:
                watchEventType = WatchCallback.WatchEventType.NodeDataChanged;
                break;
              case NodeChildrenChanged:
                watchEventType = WatchCallback.WatchEventType.NodeChildrenChanged;
                break;

              default:
                throw new RuntimeException("Invalid integer value for conversion to EventType");
            }
            watcher.processWatch(watchedEvent.getPath(), watchEventType);
          }
        };
  }

  private ZkWatcherCallback() {
  }
}