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.RetryLoop; import org.apache.curator.drivers.OperationTrace; import org.apache.curator.framework.api.*; import org.apache.curator.utils.ThreadUtils; import org.apache.zookeeper.AsyncCallback; import org.apache.zookeeper.KeeperException; import org.apache.zookeeper.Watcher; import org.apache.zookeeper.data.Stat; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import java.util.concurrent.Callable; import java.util.concurrent.Executor; class GetDataBuilderImpl implements GetDataBuilder, BackgroundOperation<String>, ErrorListenerPathable<byte[]> { private final Logger log = LoggerFactory.getLogger(getClass()); private final CuratorFrameworkImpl client; private Stat responseStat; private Watching watching; private Backgrounding backgrounding; private boolean decompress; GetDataBuilderImpl(CuratorFrameworkImpl client) { this.client = client; responseStat = null; watching = new Watching(); backgrounding = new Backgrounding(); decompress = false; } @Override public GetDataWatchBackgroundStatable decompressed() { decompress = true; return new GetDataWatchBackgroundStatable() { @Override public ErrorListenerPathable<byte[]> inBackground() { return GetDataBuilderImpl.this.inBackground(); } @Override public ErrorListenerPathable<byte[]> inBackground(BackgroundCallback callback, Object context) { return GetDataBuilderImpl.this.inBackground(callback, context); } @Override public ErrorListenerPathable<byte[]> inBackground(BackgroundCallback callback, Object context, Executor executor) { return GetDataBuilderImpl.this.inBackground(callback, context, executor); } @Override public ErrorListenerPathable<byte[]> inBackground(Object context) { return GetDataBuilderImpl.this.inBackground(context); } @Override public ErrorListenerPathable<byte[]> inBackground(BackgroundCallback callback) { return GetDataBuilderImpl.this.inBackground(callback); } @Override public ErrorListenerPathable<byte[]> inBackground(BackgroundCallback callback, Executor executor) { return GetDataBuilderImpl.this.inBackground(callback, executor); } @Override public byte[] forPath(String path) throws Exception { return GetDataBuilderImpl.this.forPath(path); } @Override public WatchPathable<byte[]> storingStatIn(Stat stat) { return GetDataBuilderImpl.this.storingStatIn(stat); } @Override public BackgroundPathable<byte[]> watched() { return GetDataBuilderImpl.this.watched(); } @Override public BackgroundPathable<byte[]> usingWatcher(Watcher watcher) { return GetDataBuilderImpl.this.usingWatcher(watcher); } @Override public BackgroundPathable<byte[]> usingWatcher(CuratorWatcher watcher) { return GetDataBuilderImpl.this.usingWatcher(watcher); } }; } @Override public WatchPathable<byte[]> storingStatIn(Stat stat) { this.responseStat = stat; return new WatchPathable<byte[]>() { @Override public byte[] forPath(String path) throws Exception { return GetDataBuilderImpl.this.forPath(path); } @Override public Pathable<byte[]> watched() { GetDataBuilderImpl.this.watched(); return GetDataBuilderImpl.this; } @Override public Pathable<byte[]> usingWatcher(Watcher watcher) { GetDataBuilderImpl.this.usingWatcher(watcher); return GetDataBuilderImpl.this; } @Override public Pathable<byte[]> usingWatcher(CuratorWatcher watcher) { GetDataBuilderImpl.this.usingWatcher(watcher); return GetDataBuilderImpl.this; } }; } @Override public ErrorListenerPathable<byte[]> inBackground(BackgroundCallback callback, Object context) { backgrounding = new Backgrounding(callback, context); return this; } @Override public ErrorListenerPathable<byte[]> inBackground(BackgroundCallback callback, Object context, Executor executor) { backgrounding = new Backgrounding(client, callback, context, executor); return this; } @Override public ErrorListenerPathable<byte[]> inBackground(BackgroundCallback callback) { backgrounding = new Backgrounding(callback); return this; } @Override public ErrorListenerPathable<byte[]> inBackground(BackgroundCallback callback, Executor executor) { backgrounding = new Backgrounding(client, callback, executor); return this; } @Override public ErrorListenerPathable<byte[]> inBackground() { backgrounding = new Backgrounding(true); return this; } @Override public ErrorListenerPathable<byte[]> inBackground(Object context) { backgrounding = new Backgrounding(context); return this; } @Override public Pathable<byte[]> withUnhandledErrorListener(UnhandledErrorListener listener) { backgrounding = new Backgrounding(backgrounding, listener); return this; } @Override public BackgroundPathable<byte[]> watched() { watching = new Watching(true); return this; } @Override public BackgroundPathable<byte[]> usingWatcher(Watcher watcher) { watching = new Watching(client, watcher); return this; } @Override public BackgroundPathable<byte[]> usingWatcher(CuratorWatcher watcher) { watching = new Watching(client, watcher); return this; } @Override public void performBackgroundOperation(final OperationAndData<String> operationAndData) throws Exception { try { final OperationTrace trace = client.getZookeeperClient() .startAdvancedTracer("GetDataBuilderImpl-Background"); AsyncCallback.DataCallback callback = new AsyncCallback.DataCallback() { @Override public void processResult(int rc, String path, Object ctx, byte[] data, Stat stat) { trace.setReturnCode(rc).setResponseBytesLength(data).setPath(path) .setWithWatcher(watching.getWatcher() != null).setStat(stat).commit(); if (decompress && (data != null)) { try { data = client.getCompressionProvider().decompress(path, data); } catch (Exception e) { ThreadUtils.checkInterrupted(e); log.error("Decompressing for path: " + path, e); rc = KeeperException.Code.DATAINCONSISTENCY.intValue(); } } CuratorEvent event = new CuratorEventImpl(client, CuratorEventType.GET_DATA, rc, path, null, ctx, stat, data, null, null, null); client.processBackgroundOperation(operationAndData, event); } }; if (watching.isWatched()) { client.getZooKeeper().getData(operationAndData.getData(), true, callback, backgrounding.getContext()); } else { client.getZooKeeper().getData(operationAndData.getData(), watching.getWatcher(), callback, backgrounding.getContext()); } } catch (Throwable e) { backgrounding.checkError(e); } } @Override public byte[] forPath(String path) throws Exception { path = client.fixForNamespace(path); byte[] responseData = null; if (backgrounding.inBackground()) { client.processBackgroundOperation(new OperationAndData<String>(this, path, backgrounding.getCallback(), null, backgrounding.getContext()), null); } else { responseData = pathInForeground(path); } return responseData; } private byte[] pathInForeground(final String path) throws Exception { OperationTrace trace = client.getZookeeperClient().startAdvancedTracer("GetDataBuilderImpl-Foreground"); byte[] responseData = RetryLoop.callWithRetry(client.getZookeeperClient(), new Callable<byte[]>() { @Override public byte[] call() throws Exception { byte[] responseData; if (watching.isWatched()) { responseData = client.getZooKeeper().getData(path, true, responseStat); } else { responseData = client.getZooKeeper().getData(path, watching.getWatcher(), responseStat); } return responseData; } }); trace.setResponseBytesLength(responseData).setPath(path).setWithWatcher(watching.getWatcher() != null) .setStat(responseStat).commit(); return decompress ? client.getCompressionProvider().decompress(path, responseData) : responseData; } }