curator-master/curator-framework/src/main/java/org/apache/curator/framework/imps/GetDataBuilderImpl.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.curator.framework.imps;

import java.util.concurrent.Callable;
import java.util.concurrent.Executor;
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.apache.zookeeper.server.DataTree;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public 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(client);
        backgrounding = new Backgrounding();
        decompress = false;
    }

    public GetDataBuilderImpl(
            CuratorFrameworkImpl client,
            Stat responseStat,
            Watcher watcher,
            Backgrounding backgrounding,
            boolean decompress) {
        this.client = client;
        this.responseStat = responseStat;
        this.watching = new Watching(client, watcher);
        this.backgrounding = backgrounding;
        this.decompress = decompress;
    }

    @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(client, 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 CuratorEventType getBackgroundEventType() {
        return CuratorEventType.GET_DATA;
    }

    @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) {
                    watching.commitWatcher(rc, false);
                    trace.setReturnCode(rc)
                            .setResponseBytesLength(data)
                            .setPath(path)
                            .setWithWatcher(watching.hasWatcher())
                            .setStat(stat)
                            .commit();
                    if ((responseStat != null) && (stat != null)) {
                        DataTree.copyStat(stat, responseStat);
                    }
                    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, 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(operationAndData.getData()),
                                callback,
                                backgrounding.getContext());
            }
        } catch (Throwable e) {
            backgrounding.checkError(e, watching);
        }
    }

    @Override
    public byte[] forPath(String path) throws Exception {
        client.getSchemaSet().getSchema(path).validateWatch(path, watching.isWatched() || watching.hasWatcher());

        path = client.fixForNamespace(path);

        byte[] responseData = null;
        if (backgrounding.inBackground()) {
            client.processBackgroundOperation(
                    new OperationAndData<String>(
                            this, path, backgrounding.getCallback(), null, backgrounding.getContext(), watching),
                    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(path), responseStat);
                    watching.commitWatcher(KeeperException.NoNodeException.Code.OK.intValue(), false);
                }
                return responseData;
            }
        });
        trace.setResponseBytesLength(responseData)
                .setPath(path)
                .setWithWatcher(watching.hasWatcher())
                .setStat(responseStat)
                .commit();

        return decompress ? client.getCompressionProvider().decompress(path, responseData) : responseData;
    }
}
