/**
* Copyright 2010 the original author or authors.
*
* Licensed 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.I0Itec.zkclient;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.LinkedBlockingDeque;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
import org.I0Itec.zkclient.exception.ZkException;
import org.I0Itec.zkclient.exception.ZkInterruptedException;
import org.I0Itec.zkclient.exception.ZkNoNodeException;
import org.apache.zookeeper.CreateMode;
import org.apache.zookeeper.KeeperException;
import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.KeeperException.Code;
import org.apache.zookeeper.Watcher.Event.EventType;
import org.apache.zookeeper.Watcher.Event.KeeperState;
import org.apache.zookeeper.ZooKeeper.States;
import org.apache.zookeeper.data.Stat;
public class InMemoryConnection implements IZkConnection {
private Lock _lock = new ReentrantLock(true);
private Map<String, byte[]> _data = new HashMap<String, byte[]>();
private Map<String, Long> _creationTime = new HashMap<String, Long>();
private Set<String> _dataWatches = new HashSet<String>();
private Set<String> _nodeWatches = new HashSet<String>();
private EventThread _eventThread;
private class EventThread extends Thread {
private Watcher _watcher;
private BlockingQueue<WatchedEvent> _blockingQueue = new LinkedBlockingDeque<WatchedEvent>();
public EventThread(Watcher watcher) {
_watcher = watcher;
}
@Override
public void run() {
try {
while (true) {
_watcher.process(_blockingQueue.take());
}
} catch (InterruptedException e) {
// stop event thread
}
}
public void send(WatchedEvent event) {
_blockingQueue.add(event);
}
}
public InMemoryConnection() {
try {
create("/", null, CreateMode.PERSISTENT);
} catch (KeeperException e) {
throw ZkException.create(e);
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
throw new ZkInterruptedException(e);
}
}
@Override
public void close() throws InterruptedException {
_lock.lockInterruptibly();
try {
if (_eventThread != null) {
_eventThread.interrupt();
_eventThread.join();
_eventThread = null;
}
} finally {
_lock.unlock();
}
}
@Override
public void connect(Watcher watcher) {
_lock.lock();
try {
if (_eventThread != null) {
throw new IllegalStateException("Already connected.");
}
_eventThread = new EventThread(watcher);
_eventThread.start();
_eventThread.send(new WatchedEvent(null, KeeperState.SyncConnected, null));
} finally {
_lock.unlock();
}
}
@Override
public String create(String path, byte[] data, CreateMode mode) throws KeeperException, InterruptedException {
_lock.lock();
try {
if (exists(path, false)) {
throw new KeeperException.NodeExistsException();
}
_data.put(path, data);
_creationTime.put(path, System.currentTimeMillis());
checkWatch(_nodeWatches, path, EventType.NodeCreated);
// we also need to send a child change event for the parent
String parentPath = getParentPath(path);
if (parentPath != null) {
checkWatch(_nodeWatches, parentPath, EventType.NodeChildrenChanged);
}
return path;
} finally {
_lock.unlock();
}
}
private String getParentPath(String path) {
int lastIndexOf = path.lastIndexOf("/");
if (lastIndexOf == -1 || lastIndexOf == 0) {
return null;
}
return path.substring(0, lastIndexOf);
}
@Override
public void delete(String path) throws InterruptedException, KeeperException {
_lock.lock();
try {
if (!exists(path, false)) {
throw new KeeperException.NoNodeException();
}
_data.remove(path);
_creationTime.remove(path);
checkWatch(_nodeWatches, path, EventType.NodeDeleted);
String parentPath = getParentPath(path);
if (parentPath != null) {
checkWatch(_nodeWatches, parentPath, EventType.NodeChildrenChanged);
}
} finally {
_lock.unlock();
}
}
@Override
public boolean exists(String path, boolean watch) throws KeeperException, InterruptedException {
_lock.lock();
try {
if (watch) {
installWatch(_nodeWatches, path);
}
return _data.containsKey(path);
} finally {
_lock.unlock();
}
}
private void installWatch(Set<String> watches, String path) {
watches.add(path);
}
@Override
public List<String> getChildren(String path, boolean watch) throws KeeperException, InterruptedException {
if (!exists(path, false)) {
throw KeeperException.create(Code.NONODE, path);
}
if (exists(path, false) && watch) {
installWatch(_nodeWatches, path);
}
ArrayList<String> children = new ArrayList<String>();
String[] directoryStack = path.split("/");
Set<String> keySet = _data.keySet();
for (String string : keySet) {
if (string.startsWith(path)) {
String[] stack = string.split("/");
// is one folder level below the one we loockig for and starts
// with path...
if (stack.length == directoryStack.length + 1) {
children.add(stack[stack.length - 1]);
}
}
}
return children;
}
@Override
public States getZookeeperState() {
_lock.lock();
try {
if (_eventThread == null) {
return States.CLOSED;
}
return States.CONNECTED;
} finally {
_lock.unlock();
}
}
@Override
public byte[] readData(String path, Stat stat, boolean watch) throws KeeperException, InterruptedException {
if (watch) {
installWatch(_dataWatches, path);
}
_lock.lock();
try {
byte[] bs = _data.get(path);
if (bs == null) {
throw new ZkNoNodeException(new KeeperException.NoNodeException());
}
return bs;
} finally {
_lock.unlock();
}
}
@Override
public void writeData(String path, byte[] data, int expectedVersion) throws KeeperException, InterruptedException {
_lock.lock();
try {
checkWatch(_dataWatches, path, EventType.NodeDataChanged);
if (!exists(path, false)) {
throw new KeeperException.NoNodeException();
}
_data.put(path, data);
String parentPath = getParentPath(path);
if (parentPath != null) {
checkWatch(_nodeWatches, parentPath, EventType.NodeChildrenChanged);
}
} finally {
_lock.unlock();
}
}
private void checkWatch(Set<String> watches, String path, EventType eventType) {
if (watches.contains(path)) {
watches.remove(path);
_eventThread.send(new WatchedEvent(eventType, KeeperState.SyncConnected, path));
}
}
@Override
public long getCreateTime(String path) {
Long time = _creationTime.get(path);
if (time == null) {
return -1;
}
return time;
}
@Override
public String getServers() {
return "mem";
}
}