Java tutorial
/** * 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.curator.framework.imps; import org.apache.curator.framework.api.CuratorWatcher; import org.apache.curator.utils.ThreadUtils; import org.apache.zookeeper.WatchedEvent; import org.apache.zookeeper.Watcher; import java.io.Closeable; class NamespaceWatcher implements Watcher, Closeable { private volatile CuratorFrameworkImpl client; private volatile Watcher actualWatcher; private volatile CuratorWatcher curatorWatcher; NamespaceWatcher(CuratorFrameworkImpl client, Watcher actualWatcher) { this.client = client; this.actualWatcher = actualWatcher; this.curatorWatcher = null; } NamespaceWatcher(CuratorFrameworkImpl client, CuratorWatcher curatorWatcher) { this.client = client; this.actualWatcher = null; this.curatorWatcher = curatorWatcher; } @Override public void close() { client = null; actualWatcher = null; curatorWatcher = null; } @Override public void process(WatchedEvent event) { if (client != null) { if (actualWatcher != null) { actualWatcher.process(new NamespaceWatchedEvent(client, event)); } else if (curatorWatcher != null) { try { curatorWatcher.process(new NamespaceWatchedEvent(client, event)); } catch (Exception e) { ThreadUtils.checkInterrupted(e); client.logError("Watcher exception", e); } } } } }