curator-master/curator-framework/src/main/java/org/apache/curator/framework/imps/AddWatchBuilderImpl.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.Executor;
import org.apache.curator.RetryLoop;
import org.apache.curator.drivers.OperationTrace;
import org.apache.curator.framework.api.AddWatchBuilder;
import org.apache.curator.framework.api.AddWatchBuilder2;
import org.apache.curator.framework.api.BackgroundCallback;
import org.apache.curator.framework.api.CuratorEvent;
import org.apache.curator.framework.api.CuratorEventType;
import org.apache.curator.framework.api.CuratorWatcher;
import org.apache.curator.framework.api.Pathable;
import org.apache.curator.framework.api.WatchableBase;
import org.apache.zookeeper.AddWatchMode;
import org.apache.zookeeper.Watcher;

public class AddWatchBuilderImpl implements AddWatchBuilder, Pathable<Void>, BackgroundOperation<String> {
    private final CuratorFrameworkImpl client;
    private Watching watching;
    private Backgrounding backgrounding = new Backgrounding();
    private AddWatchMode mode = AddWatchMode.PERSISTENT_RECURSIVE;

    AddWatchBuilderImpl(CuratorFrameworkImpl client) {
        this.client = client;
        watching = new Watching(client, true);
    }

    public AddWatchBuilderImpl(
            CuratorFrameworkImpl client, Watching watching, Backgrounding backgrounding, AddWatchMode mode) {
        this.client = client;
        this.watching = watching;
        this.backgrounding = backgrounding;
        this.mode = mode;
    }

    @Override
    public WatchableBase<Pathable<Void>> inBackground() {
        backgrounding = new Backgrounding();
        return this;
    }

    @Override
    public AddWatchBuilder2 withMode(AddWatchMode mode) {
        this.mode = mode;
        return this;
    }

    @Override
    public Pathable<Void> usingWatcher(Watcher watcher) {
        watching = new Watching(client, watcher);
        return this;
    }

    @Override
    public Pathable<Void> usingWatcher(CuratorWatcher watcher) {
        watching = new Watching(client, watcher);
        return this;
    }

    @Override
    public WatchableBase<Pathable<Void>> inBackground(Object context) {
        backgrounding = new Backgrounding(context);
        return this;
    }

    @Override
    public WatchableBase<Pathable<Void>> inBackground(BackgroundCallback callback) {
        backgrounding = new Backgrounding(callback);
        return this;
    }

    @Override
    public WatchableBase<Pathable<Void>> inBackground(BackgroundCallback callback, Object context) {
        backgrounding = new Backgrounding(callback, context);
        return this;
    }

    @Override
    public WatchableBase<Pathable<Void>> inBackground(BackgroundCallback callback, Executor executor) {
        backgrounding = new Backgrounding(callback, executor);
        return this;
    }

    @Override
    public WatchableBase<Pathable<Void>> inBackground(BackgroundCallback callback, Object context, Executor executor) {
        backgrounding = new Backgrounding(client, callback, context, executor);
        return this;
    }

    @Override
    public Void forPath(String path) throws Exception {
        if (backgrounding.inBackground()) {
            client.processBackgroundOperation(
                    new OperationAndData<>(
                            this, path, backgrounding.getCallback(), null, backgrounding.getContext(), watching),
                    null);
        } else {
            pathInForeground(path);
        }
        return null;
    }

    @Override
    public CuratorEventType getBackgroundEventType() {
        return CuratorEventType.ADD_WATCH;
    }

    @Override
    public void performBackgroundOperation(final OperationAndData<String> data) throws Exception {
        String path = data.getData();
        String fixedPath = client.fixForNamespace(path);
        try {
            final OperationTrace trace =
                    client.getZookeeperClient().startAdvancedTracer("AddWatchBuilderImpl-Background");
            if (watching.isWatched()) {
                client.getZooKeeper()
                        .addWatch(
                                fixedPath,
                                mode,
                                (rc, path1, ctx) -> {
                                    trace.setReturnCode(rc)
                                            .setWithWatcher(true)
                                            .setPath(path1)
                                            .commit();
                                    CuratorEvent event = new CuratorEventImpl(
                                            client,
                                            CuratorEventType.ADD_WATCH,
                                            rc,
                                            path1,
                                            null,
                                            ctx,
                                            null,
                                            null,
                                            null,
                                            null,
                                            null,
                                            null);
                                    client.processBackgroundOperation(data, event);
                                },
                                backgrounding.getContext());
            } else {
                client.getZooKeeper()
                        .addWatch(
                                fixedPath,
                                watching.getWatcher(path),
                                mode,
                                (rc, path1, ctx) -> {
                                    trace.setReturnCode(rc)
                                            .setWithWatcher(true)
                                            .setPath(path1)
                                            .commit();
                                    CuratorEvent event = new CuratorEventImpl(
                                            client,
                                            CuratorEventType.ADD_WATCH,
                                            rc,
                                            path1,
                                            null,
                                            ctx,
                                            null,
                                            null,
                                            null,
                                            null,
                                            null,
                                            null);
                                    client.processBackgroundOperation(data, event);
                                },
                                backgrounding.getContext());
            }
        } catch (Throwable e) {
            backgrounding.checkError(e, watching);
        }
    }

    private void pathInForeground(final String path) throws Exception {
        final String fixedPath = client.fixForNamespace(path);
        OperationTrace trace = client.getZookeeperClient().startAdvancedTracer("AddWatchBuilderImpl-Foreground");
        RetryLoop.callWithRetry(client.getZookeeperClient(), () -> {
            if (watching.isWatched()) {
                client.getZooKeeper().addWatch(fixedPath, mode);
            } else {
                client.getZooKeeper().addWatch(fixedPath, watching.getWatcher(path), mode);
            }
            return null;
        });
        trace.setPath(fixedPath).setWithWatcher(true).commit();
    }
}
