curator-master/curator-framework/src/main/java/org/apache/curator/framework/imps/ExistsBuilderImpl.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.List;
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.ZKPaths;
import org.apache.zookeeper.AsyncCallback;
import org.apache.zookeeper.KeeperException;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.data.ACL;
import org.apache.zookeeper.data.Stat;

public class ExistsBuilderImpl
        implements ExistsBuilder, BackgroundOperation<String>, ErrorListenerPathable<Stat>, ACLableExistBuilderMain {
    private final CuratorFrameworkImpl client;
    private Backgrounding backgrounding;
    private Watching watching;
    private boolean createParentsIfNeeded;
    private boolean createParentContainersIfNeeded;
    private ACLing acling;

    ExistsBuilderImpl(CuratorFrameworkImpl client) {
        this(client, new Backgrounding(), null, false, false);
    }

    public ExistsBuilderImpl(
            CuratorFrameworkImpl client,
            Backgrounding backgrounding,
            Watcher watcher,
            boolean createParentsIfNeeded,
            boolean createParentContainersIfNeeded) {
        this.client = client;
        this.backgrounding = backgrounding;
        this.watching = new Watching(client, watcher);
        this.createParentsIfNeeded = createParentsIfNeeded;
        this.createParentContainersIfNeeded = createParentContainersIfNeeded;
        this.acling = new ACLing(client.getAclProvider());
    }

    @Override
    public ACLableExistBuilderMain creatingParentsIfNeeded() {
        createParentContainersIfNeeded = false;
        createParentsIfNeeded = true;
        return this;
    }

    @Override
    public ACLableExistBuilderMain creatingParentContainersIfNeeded() {
        createParentContainersIfNeeded = true;
        createParentsIfNeeded = false;
        return this;
    }

    @Override
    public ExistsBuilderMain withACL(List<ACL> aclList) {
        acling = new ACLing(client.getAclProvider(), aclList, true);
        return this;
    }

    @Override
    public BackgroundPathable<Stat> watched() {
        watching = new Watching(client, true);
        return this;
    }

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

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

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

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

    @Override
    public ErrorListenerPathable<Stat> inBackground(BackgroundCallback callback) {
        backgrounding = new Backgrounding(callback);
        return this;
    }

    @Override
    public ErrorListenerPathable<Stat> inBackground(BackgroundCallback callback, Executor executor) {
        backgrounding = new Backgrounding(client, callback, executor);
        return this;
    }

    @Override
    public ErrorListenerPathable<Stat> inBackground() {
        backgrounding = new Backgrounding(true);
        return this;
    }

    @Override
    public ErrorListenerPathable<Stat> inBackground(Object context) {
        backgrounding = new Backgrounding(context);
        return this;
    }

    @Override
    public Pathable<Stat> withUnhandledErrorListener(UnhandledErrorListener listener) {
        backgrounding = new Backgrounding(backgrounding, listener);
        return this;
    }

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

    @Override
    public void performBackgroundOperation(final OperationAndData<String> operationAndData) throws Exception {
        try {
            final OperationTrace trace =
                    client.getZookeeperClient().startAdvancedTracer("ExistsBuilderImpl-Background");
            AsyncCallback.StatCallback callback = new AsyncCallback.StatCallback() {
                @Override
                public void processResult(int rc, String path, Object ctx, Stat stat) {
                    watching.commitWatcher(rc, true);
                    trace.setReturnCode(rc)
                            .setPath(path)
                            .setWithWatcher(watching.hasWatcher())
                            .setStat(stat)
                            .commit();
                    CuratorEvent event = new CuratorEventImpl(
                            client, CuratorEventType.EXISTS, rc, path, null, ctx, stat, null, null, null, null, null);
                    client.processBackgroundOperation(operationAndData, event);
                }
            };
            if (watching.isWatched()) {
                client.getZooKeeper().exists(operationAndData.getData(), true, callback, backgrounding.getContext());
            } else {
                client.getZooKeeper()
                        .exists(
                                operationAndData.getData(),
                                watching.getWatcher(operationAndData.getData()),
                                callback,
                                backgrounding.getContext());
            }
        } catch (Throwable e) {
            backgrounding.checkError(e, watching);
        }
    }

    @Override
    public Stat forPath(String path) throws Exception {
        path = client.fixForNamespace(path);

        client.getSchemaSet().getSchema(path).validateWatch(path, watching.isWatched() || watching.hasWatcher());

        Stat returnStat = null;
        if (backgrounding.inBackground()) {
            OperationAndData<String> operationAndData = new OperationAndData<String>(
                    this, path, backgrounding.getCallback(), null, backgrounding.getContext(), watching);
            if (createParentContainersIfNeeded || createParentsIfNeeded) {
                CreateBuilderImpl.backgroundCreateParentsThenNode(
                        client,
                        operationAndData,
                        operationAndData.getData(),
                        backgrounding,
                        acling.getACLProviderForParents(),
                        createParentContainersIfNeeded);
            } else {
                client.processBackgroundOperation(operationAndData, null);
            }
        } else {
            returnStat = pathInForeground(path);
        }

        return returnStat;
    }

    private Stat pathInForeground(final String path) throws Exception {
        if (createParentContainersIfNeeded || createParentsIfNeeded) {
            final String parent = ZKPaths.getPathAndNode(path).getPath();
            if (!parent.equals(ZKPaths.PATH_SEPARATOR)) {
                OperationTrace trace =
                        client.getZookeeperClient().startAdvancedTracer("ExistsBuilderImpl-Foreground-CreateParents");
                RetryLoop.callWithRetry(client.getZookeeperClient(), new Callable<Void>() {
                    @Override
                    public Void call() throws Exception {
                        try {
                            ZKPaths.mkdirs(
                                    client.getZooKeeper(),
                                    parent,
                                    true,
                                    acling.getACLProviderForParents(),
                                    createParentContainersIfNeeded);
                        } catch (KeeperException.NodeExistsException e) {
                            // ignore
                        } catch (KeeperException.NoNodeException e) {
                            // ignore
                        }
                        return null;
                    }
                });
                trace.setPath(path).commit();
            }
        }
        return pathInForegroundStandard(path);
    }

    private Stat pathInForegroundStandard(final String path) throws Exception {
        OperationTrace trace = client.getZookeeperClient().startAdvancedTracer("ExistsBuilderImpl-Foreground");
        Stat returnStat = RetryLoop.callWithRetry(client.getZookeeperClient(), new Callable<Stat>() {
            @Override
            public Stat call() throws Exception {
                Stat returnStat;
                if (watching.isWatched()) {
                    returnStat = client.getZooKeeper().exists(path, true);
                } else {
                    returnStat = client.getZooKeeper().exists(path, watching.getWatcher(path));
                    int rc = (returnStat != null)
                            ? KeeperException.NoNodeException.Code.OK.intValue()
                            : KeeperException.NoNodeException.Code.NONODE.intValue();
                    watching.commitWatcher(rc, true);
                }
                return returnStat;
            }
        });
        trace.setPath(path)
                .setWithWatcher(watching.hasWatcher())
                .setStat(returnStat)
                .commit();
        return returnStat;
    }
}
