You are viewing a plain text version of this content. The canonical link for it is here.
Posted to commits@zookeeper.apache.org by an...@apache.org on 2018/07/17 08:38:45 UTC

[05/10] zookeeper git commit: ZOOKEEPER-3033: branch-3.4 - MAVEN MIGRATION - Step 1.2 - zk-recipes

http://git-wip-us.apache.org/repos/asf/zookeeper/blob/e5b4b94d/zookeeper-recipes/election/src/java/org/apache/zookeeper/recipes/leader/LeaderElectionAware.java
----------------------------------------------------------------------
diff --git a/zookeeper-recipes/election/src/java/org/apache/zookeeper/recipes/leader/LeaderElectionAware.java b/zookeeper-recipes/election/src/java/org/apache/zookeeper/recipes/leader/LeaderElectionAware.java
new file mode 100644
index 0000000..6c32ebc
--- /dev/null
+++ b/zookeeper-recipes/election/src/java/org/apache/zookeeper/recipes/leader/LeaderElectionAware.java
@@ -0,0 +1,37 @@
+/*
+ * 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.zookeeper.recipes.leader;
+
+import org.apache.zookeeper.recipes.leader.LeaderElectionSupport.EventType;
+
+/**
+ * An interface to be implemented by clients that want to receive election
+ * events.
+ */
+public interface LeaderElectionAware {
+
+  /**
+   * Called during each state transition. Current, low level events are provided
+   * at the beginning and end of each state. For instance, START may be followed
+   * by OFFER_START, OFFER_COMPLETE, DETERMINE_START, DETERMINE_COMPLETE, and so
+   * on.
+   * 
+   * @param eventType
+   */
+  public void onElectionEvent(EventType eventType);
+
+}

http://git-wip-us.apache.org/repos/asf/zookeeper/blob/e5b4b94d/zookeeper-recipes/election/src/java/org/apache/zookeeper/recipes/leader/LeaderElectionSupport.java
----------------------------------------------------------------------
diff --git a/zookeeper-recipes/election/src/java/org/apache/zookeeper/recipes/leader/LeaderElectionSupport.java b/zookeeper-recipes/election/src/java/org/apache/zookeeper/recipes/leader/LeaderElectionSupport.java
new file mode 100644
index 0000000..8f8ae20
--- /dev/null
+++ b/zookeeper-recipes/election/src/java/org/apache/zookeeper/recipes/leader/LeaderElectionSupport.java
@@ -0,0 +1,461 @@
+/*
+ * 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.zookeeper.recipes.leader;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+import org.apache.zookeeper.CreateMode;
+import org.apache.zookeeper.KeeperException;
+import org.apache.zookeeper.WatchedEvent;
+import org.apache.zookeeper.Watcher;
+import org.apache.zookeeper.ZooDefs;
+import org.apache.zookeeper.ZooKeeper;
+import org.apache.zookeeper.data.Stat;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * <p>
+ * A leader election support library implementing the ZooKeeper election recipe.
+ * </p>
+ * <p>
+ * This support library is meant to simplify the construction of an exclusive
+ * leader system on top of Apache ZooKeeper. Any application that can become the
+ * leader (usually a process that provides a service, exclusively) would
+ * configure an instance of this class with their hostname, at least one
+ * listener (an implementation of {@link LeaderElectionAware}), and either an
+ * instance of {@link ZooKeeper} or the proper connection information. Once
+ * configured, invoking {@link #start()} will cause the client to connect to
+ * ZooKeeper and create a leader offer. The library then determines if it has
+ * been elected the leader using the algorithm described below. The client
+ * application can follow all state transitions via the listener callback.
+ * </p>
+ * <p>
+ * Leader election algorithm
+ * </p>
+ * <p>
+ * The library starts in a START state. Through each state transition, a state
+ * start and a state complete event are sent to all listeners. When
+ * {@link #start()} is called, a leader offer is created in ZooKeeper. A leader
+ * offer is an ephemeral sequential node that indicates a process that can act
+ * as a leader for this service. A read of all leader offers is then performed.
+ * The offer with the lowest sequence number is said to be the leader. The
+ * process elected leader will transition to the leader state. All other
+ * processes will transition to a ready state. Internally, the library creates a
+ * ZooKeeper watch on the leader offer with the sequence ID of N - 1 (where N is
+ * the process's sequence ID). If that offer disappears due to a process
+ * failure, the watching process will run through the election determination
+ * process again to see if it should become the leader. Note that sequence ID
+ * may not be contiguous due to failed processes. A process may revoke its offer
+ * to be the leader at any time by calling {@link #stop()}.
+ * </p>
+ * <p>
+ * Guarantees (not) Made and Caveats
+ * </p>
+ * <p>
+ * <ul>
+ * <li>It is possible for a (poorly implemented) process to create a leader
+ * offer, get the lowest sequence ID, but have something terrible occur where it
+ * maintains its connection to ZK (and thus its ephemeral leader offer node) but
+ * doesn't actually provide the service in question. It is up to the user to
+ * ensure any failure to become the leader - and whatever that means in the
+ * context of the user's application - results in a revocation of its leader
+ * offer (i.e. that {@link #stop()} is called).</li>
+ * <li>It is possible for ZK timeouts and retries to play a role in service
+ * liveliness. In other words, if process A has the lowest sequence ID but
+ * requires a few attempts to read the other leader offers' sequence IDs,
+ * election can seem slow. Users should apply timeouts during the determination
+ * process if they need to hit a specific SLA.</li>
+ * <li>The library makes a "best effort" to detect catastrophic failures of the
+ * process. It is possible that an unforeseen event results in (for instance) an
+ * unchecked exception that propagates passed normal error handling code. This
+ * normally doesn't matter as the same exception would almost certain destroy
+ * the entire process and thus the connection to ZK and the leader offer
+ * resulting in another round of leader determination.</li>
+ * </ul>
+ * </p>
+ */
+public class LeaderElectionSupport implements Watcher {
+
+  private static final Logger logger = LoggerFactory
+      .getLogger(LeaderElectionSupport.class);
+
+  private ZooKeeper zooKeeper;
+
+  private State state;
+  private Set<LeaderElectionAware> listeners;
+
+  private String rootNodeName;
+  private LeaderOffer leaderOffer;
+  private String hostName;
+
+  public LeaderElectionSupport() {
+    state = State.STOP;
+    listeners = Collections.synchronizedSet(new HashSet<LeaderElectionAware>());
+  }
+
+  /**
+   * <p>
+   * Start the election process. This method will create a leader offer,
+   * determine its status, and either become the leader or become ready. If an
+   * instance of {@link ZooKeeper} has not yet been configured by the user, a
+   * new instance is created using the connectString and sessionTime specified.
+   * </p>
+   * <p>
+   * Any (anticipated) failures result in a failed event being sent to all
+   * listeners.
+   * </p>
+   */
+  public synchronized void start() {
+    state = State.START;
+    dispatchEvent(EventType.START);
+
+    logger.info("Starting leader election support");
+
+    if (zooKeeper == null) {
+      throw new IllegalStateException(
+          "No instance of zookeeper provided. Hint: use setZooKeeper()");
+    }
+
+    if (hostName == null) {
+      throw new IllegalStateException(
+          "No hostname provided. Hint: use setHostName()");
+    }
+
+    try {
+      makeOffer();
+      determineElectionStatus();
+    } catch (KeeperException e) {
+      becomeFailed(e);
+      return;
+    } catch (InterruptedException e) {
+      becomeFailed(e);
+      return;
+    }
+  }
+
+  /**
+   * Stops all election services, revokes any outstanding leader offers, and
+   * disconnects from ZooKeeper.
+   */
+  public synchronized void stop() {
+    state = State.STOP;
+    dispatchEvent(EventType.STOP_START);
+
+    logger.info("Stopping leader election support");
+
+    if (leaderOffer != null) {
+      try {
+        zooKeeper.delete(leaderOffer.getNodePath(), -1);
+        logger.info("Removed leader offer {}", leaderOffer.getNodePath());
+      } catch (InterruptedException e) {
+        becomeFailed(e);
+      } catch (KeeperException e) {
+        becomeFailed(e);
+      }
+    }
+
+    dispatchEvent(EventType.STOP_COMPLETE);
+  }
+
+  private void makeOffer() throws KeeperException, InterruptedException {
+    state = State.OFFER;
+    dispatchEvent(EventType.OFFER_START);
+
+    leaderOffer = new LeaderOffer();
+
+    leaderOffer.setHostName(hostName);
+    leaderOffer.setNodePath(zooKeeper.create(rootNodeName + "/" + "n_",
+        hostName.getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE,
+        CreateMode.EPHEMERAL_SEQUENTIAL));
+
+    logger.debug("Created leader offer {}", leaderOffer);
+
+    dispatchEvent(EventType.OFFER_COMPLETE);
+  }
+
+  private void determineElectionStatus() throws KeeperException,
+      InterruptedException {
+
+    state = State.DETERMINE;
+    dispatchEvent(EventType.DETERMINE_START);
+
+    String[] components = leaderOffer.getNodePath().split("/");
+
+    leaderOffer.setId(Integer.valueOf(components[components.length - 1]
+        .substring("n_".length())));
+
+    List<LeaderOffer> leaderOffers = toLeaderOffers(zooKeeper.getChildren(
+        rootNodeName, false));
+
+    /*
+     * For each leader offer, find out where we fit in. If we're first, we
+     * become the leader. If we're not elected the leader, attempt to stat the
+     * offer just less than us. If they exist, watch for their failure, but if
+     * they don't, become the leader.
+     */
+    for (int i = 0; i < leaderOffers.size(); i++) {
+      LeaderOffer leaderOffer = leaderOffers.get(i);
+
+      if (leaderOffer.getId().equals(this.leaderOffer.getId())) {
+        logger.debug("There are {} leader offers. I am {} in line.",
+            leaderOffers.size(), i);
+
+        dispatchEvent(EventType.DETERMINE_COMPLETE);
+
+        if (i == 0) {
+          becomeLeader();
+        } else {
+          becomeReady(leaderOffers.get(i - 1));
+        }
+
+        /* Once we've figured out where we are, we're done. */
+        break;
+      }
+    }
+  }
+
+  private void becomeReady(LeaderOffer neighborLeaderOffer)
+      throws KeeperException, InterruptedException {
+    dispatchEvent(EventType.READY_START);
+
+    logger.info("{} not elected leader. Watching node:{}",
+        leaderOffer.getNodePath(), neighborLeaderOffer.getNodePath());
+
+    /*
+     * Make sure to pass an explicit Watcher because we could be sharing this
+     * zooKeeper instance with someone else.
+     */
+    Stat stat = zooKeeper.exists(neighborLeaderOffer.getNodePath(), this);
+
+    if (stat != null) {
+      logger.debug(
+          "We're behind {} in line and they're alive. Keeping an eye on them.",
+          neighborLeaderOffer.getNodePath());
+      state = State.READY;
+      dispatchEvent(EventType.READY_COMPLETE);
+    } else {
+      /*
+       * If the stat fails, the node has gone missing between the call to
+       * getChildren() and exists(). We need to try and become the leader.
+       */
+      logger
+          .info(
+              "We were behind {} but it looks like they died. Back to determination.",
+              neighborLeaderOffer.getNodePath());
+      determineElectionStatus();
+    }
+
+  }
+
+  private void becomeLeader() {
+    state = State.ELECTED;
+    dispatchEvent(EventType.ELECTED_START);
+
+    logger.info("Becoming leader with node:{}", leaderOffer.getNodePath());
+
+    dispatchEvent(EventType.ELECTED_COMPLETE);
+  }
+
+  private void becomeFailed(Exception e) {
+    logger.error("Failed in state {} - Exception:{}", state, e);
+
+    state = State.FAILED;
+    dispatchEvent(EventType.FAILED);
+  }
+
+  /**
+   * Fetch the (user supplied) hostname of the current leader. Note that by the
+   * time this method returns, state could have changed so do not depend on this
+   * to be strongly consistent. This method has to read all leader offers from
+   * ZooKeeper to deterime who the leader is (i.e. there is no caching) so
+   * consider the performance implications of frequent invocation. If there are
+   * no leader offers this method returns null.
+   * 
+   * @return hostname of the current leader
+   * @throws KeeperException
+   * @throws InterruptedException
+   */
+  public String getLeaderHostName() throws KeeperException,
+      InterruptedException {
+
+    List<LeaderOffer> leaderOffers = toLeaderOffers(zooKeeper.getChildren(
+        rootNodeName, false));
+
+    if (leaderOffers.size() > 0) {
+      return leaderOffers.get(0).getHostName();
+    }
+
+    return null;
+  }
+
+  private List<LeaderOffer> toLeaderOffers(List<String> strings)
+      throws KeeperException, InterruptedException {
+
+    List<LeaderOffer> leaderOffers = new ArrayList<LeaderOffer>(strings.size());
+
+    /*
+     * Turn each child of rootNodeName into a leader offer. This is a tuple of
+     * the sequence number and the node name.
+     */
+    for (String offer : strings) {
+      String hostName = new String(zooKeeper.getData(
+          rootNodeName + "/" + offer, false, null));
+
+      leaderOffers.add(new LeaderOffer(Integer.valueOf(offer.substring("n_"
+          .length())), rootNodeName + "/" + offer, hostName));
+    }
+
+    /*
+     * We sort leader offers by sequence number (which may not be zero-based or
+     * contiguous) and keep their paths handy for setting watches.
+     */
+    Collections.sort(leaderOffers, new LeaderOffer.IdComparator());
+
+    return leaderOffers;
+  }
+
+  @Override
+  public void process(WatchedEvent event) {
+    if (event.getType().equals(Watcher.Event.EventType.NodeDeleted)) {
+      if (!event.getPath().equals(leaderOffer.getNodePath())
+          && state != State.STOP) {
+        logger.debug(
+            "Node {} deleted. Need to run through the election process.",
+            event.getPath());
+        try {
+          determineElectionStatus();
+        } catch (KeeperException e) {
+          becomeFailed(e);
+        } catch (InterruptedException e) {
+          becomeFailed(e);
+        }
+      }
+    }
+  }
+
+  private void dispatchEvent(EventType eventType) {
+    logger.debug("Dispatching event:{}", eventType);
+
+    synchronized (listeners) {
+      if (listeners.size() > 0) {
+        for (LeaderElectionAware observer : listeners) {
+          observer.onElectionEvent(eventType);
+        }
+      }
+    }
+  }
+
+  /**
+   * Adds {@code listener} to the list of listeners who will receive events.
+   * 
+   * @param listener
+   */
+  public void addListener(LeaderElectionAware listener) {
+    listeners.add(listener);
+  }
+
+  /**
+   * Remove {@code listener} from the list of listeners who receive events.
+   * 
+   * @param listener
+   */
+  public void removeListener(LeaderElectionAware listener) {
+    listeners.remove(listener);
+  }
+
+  @Override
+  public String toString() {
+    return "{ state:" + state + " leaderOffer:" + leaderOffer + " zooKeeper:"
+        + zooKeeper + " hostName:" + hostName + " listeners:" + listeners
+        + " }";
+  }
+
+  /**
+   * <p>
+   * Gets the ZooKeeper root node to use for this service.
+   * </p>
+   * <p>
+   * For instance, a root node of {@code /mycompany/myservice} would be the
+   * parent of all leader offers for this service. Obviously all processes that
+   * wish to contend for leader status need to use the same root node. Note: We
+   * assume this node already exists.
+   * </p>
+   * 
+   * @return a znode path
+   */
+  public String getRootNodeName() {
+    return rootNodeName;
+  }
+
+  /**
+   * <p>
+   * Sets the ZooKeeper root node to use for this service.
+   * </p>
+   * <p>
+   * For instance, a root node of {@code /mycompany/myservice} would be the
+   * parent of all leader offers for this service. Obviously all processes that
+   * wish to contend for leader status need to use the same root node. Note: We
+   * assume this node already exists.
+   * </p>
+   */
+  public void setRootNodeName(String rootNodeName) {
+    this.rootNodeName = rootNodeName;
+  }
+
+  /**
+   * The {@link ZooKeeper} instance to use for all operations. Provided this
+   * overrides any connectString or sessionTimeout set.
+   */
+  public ZooKeeper getZooKeeper() {
+    return zooKeeper;
+  }
+
+  public void setZooKeeper(ZooKeeper zooKeeper) {
+    this.zooKeeper = zooKeeper;
+  }
+
+  /**
+   * The hostname of this process. Mostly used as a convenience for logging and
+   * to respond to {@link #getLeaderHostName()} requests.
+   */
+  public String getHostName() {
+    return hostName;
+  }
+
+  public void setHostName(String hostName) {
+    this.hostName = hostName;
+  }
+
+  /**
+   * The type of event.
+   */
+  public static enum EventType {
+    START, OFFER_START, OFFER_COMPLETE, DETERMINE_START, DETERMINE_COMPLETE, ELECTED_START, ELECTED_COMPLETE, READY_START, READY_COMPLETE, FAILED, STOP_START, STOP_COMPLETE,
+  }
+
+  /**
+   * The internal state of the election support service.
+   */
+  public static enum State {
+    START, OFFER, DETERMINE, ELECTED, READY, FAILED, STOP
+  }
+}

http://git-wip-us.apache.org/repos/asf/zookeeper/blob/e5b4b94d/zookeeper-recipes/election/src/java/org/apache/zookeeper/recipes/leader/LeaderOffer.java
----------------------------------------------------------------------
diff --git a/zookeeper-recipes/election/src/java/org/apache/zookeeper/recipes/leader/LeaderOffer.java b/zookeeper-recipes/election/src/java/org/apache/zookeeper/recipes/leader/LeaderOffer.java
new file mode 100644
index 0000000..188a6d5
--- /dev/null
+++ b/zookeeper-recipes/election/src/java/org/apache/zookeeper/recipes/leader/LeaderOffer.java
@@ -0,0 +1,84 @@
+/*
+ * 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.zookeeper.recipes.leader;
+
+import java.util.Comparator;
+
+/**
+ * A leader offer is a numeric id / path pair. The id is the sequential node id
+ * assigned by ZooKeeper where as the path is the absolute path to the ZNode.
+ */
+public class LeaderOffer {
+
+  private Integer id;
+  private String nodePath;
+  private String hostName;
+
+  public LeaderOffer() {
+    // Default constructor
+  }
+
+  public LeaderOffer(Integer id, String nodePath, String hostName) {
+    this.id = id;
+    this.nodePath = nodePath;
+    this.hostName = hostName;
+  }
+
+  @Override
+  public String toString() {
+    return "{ id:" + id + " nodePath:" + nodePath + " hostName:" + hostName
+        + " }";
+  }
+
+  public Integer getId() {
+    return id;
+  }
+
+  public void setId(Integer id) {
+    this.id = id;
+  }
+
+  public String getNodePath() {
+    return nodePath;
+  }
+
+  public void setNodePath(String nodePath) {
+    this.nodePath = nodePath;
+  }
+
+  public String getHostName() {
+    return hostName;
+  }
+
+  public void setHostName(String hostName) {
+    this.hostName = hostName;
+  }
+
+  /**
+   * Compare two instances of {@link LeaderOffer} using only the {code}id{code}
+   * member.
+   */
+  public static class IdComparator implements Comparator<LeaderOffer> {
+
+    @Override
+    public int compare(LeaderOffer o1, LeaderOffer o2) {
+      return o1.getId().compareTo(o2.getId());
+    }
+
+  }
+
+}

http://git-wip-us.apache.org/repos/asf/zookeeper/blob/e5b4b94d/zookeeper-recipes/election/test/org/apache/zookeeper/recipes/leader/LeaderElectionSupportTest.java
----------------------------------------------------------------------
diff --git a/zookeeper-recipes/election/test/org/apache/zookeeper/recipes/leader/LeaderElectionSupportTest.java b/zookeeper-recipes/election/test/org/apache/zookeeper/recipes/leader/LeaderElectionSupportTest.java
new file mode 100644
index 0000000..571d47f
--- /dev/null
+++ b/zookeeper-recipes/election/test/org/apache/zookeeper/recipes/leader/LeaderElectionSupportTest.java
@@ -0,0 +1,249 @@
+/*
+ * 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.zookeeper.recipes.leader;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import junit.framework.Assert;
+
+import org.apache.zookeeper.CreateMode;
+import org.apache.zookeeper.KeeperException;
+import org.apache.zookeeper.ZooDefs;
+import org.apache.zookeeper.ZooKeeper;
+import org.apache.zookeeper.test.ClientBase;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class LeaderElectionSupportTest extends ClientBase {
+
+  private static final Logger logger = LoggerFactory
+      .getLogger(LeaderElectionSupportTest.class);
+  private static final String testRootNode = "/" + System.currentTimeMillis()
+      + "_";
+
+  private ZooKeeper zooKeeper;
+
+  @Before
+  public void setUp() throws Exception {
+    super.setUp();
+
+    zooKeeper = createClient();
+
+    zooKeeper.create(testRootNode + Thread.currentThread().getId(),
+        new byte[0], ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
+  }
+
+  @After
+  public void tearDown() throws Exception {
+    if (zooKeeper != null) {
+      zooKeeper.delete(testRootNode + Thread.currentThread().getId(), -1);
+    }
+
+    super.tearDown();
+  }
+
+  @Test
+  public void testNode() throws IOException, InterruptedException,
+      KeeperException {
+
+    LeaderElectionSupport electionSupport = createLeaderElectionSupport();
+
+    electionSupport.start();
+    Thread.sleep(3000);
+    electionSupport.stop();
+  }
+
+  @Test
+  public void testNodes3() throws IOException, InterruptedException,
+      KeeperException {
+
+    int testIterations = 3;
+    final CountDownLatch latch = new CountDownLatch(testIterations);
+    final AtomicInteger failureCounter = new AtomicInteger();
+
+    for (int i = 0; i < testIterations; i++) {
+      runElectionSupportThread(latch, failureCounter);
+    }
+
+    Assert.assertEquals(0, failureCounter.get());
+
+    if (!latch.await(10, TimeUnit.SECONDS)) {
+      logger
+          .info(
+              "Waited for all threads to start, but timed out. We had {} failures.",
+              failureCounter);
+    }
+  }
+
+  @Test
+  public void testNodes9() throws IOException, InterruptedException,
+      KeeperException {
+
+    int testIterations = 9;
+    final CountDownLatch latch = new CountDownLatch(testIterations);
+    final AtomicInteger failureCounter = new AtomicInteger();
+
+    for (int i = 0; i < testIterations; i++) {
+      runElectionSupportThread(latch, failureCounter);
+    }
+
+    Assert.assertEquals(0, failureCounter.get());
+
+    if (!latch.await(10, TimeUnit.SECONDS)) {
+      logger
+          .info(
+              "Waited for all threads to start, but timed out. We had {} failures.",
+              failureCounter);
+    }
+  }
+
+  @Test
+  public void testNodes20() throws IOException, InterruptedException,
+      KeeperException {
+
+    int testIterations = 20;
+    final CountDownLatch latch = new CountDownLatch(testIterations);
+    final AtomicInteger failureCounter = new AtomicInteger();
+
+    for (int i = 0; i < testIterations; i++) {
+      runElectionSupportThread(latch, failureCounter);
+    }
+
+    Assert.assertEquals(0, failureCounter.get());
+
+    if (!latch.await(10, TimeUnit.SECONDS)) {
+      logger
+          .info(
+              "Waited for all threads to start, but timed out. We had {} failures.",
+              failureCounter);
+    }
+  }
+
+  @Test
+  public void testNodes100() throws IOException, InterruptedException,
+      KeeperException {
+
+    int testIterations = 100;
+    final CountDownLatch latch = new CountDownLatch(testIterations);
+    final AtomicInteger failureCounter = new AtomicInteger();
+
+    for (int i = 0; i < testIterations; i++) {
+      runElectionSupportThread(latch, failureCounter);
+    }
+
+    Assert.assertEquals(0, failureCounter.get());
+
+    if (!latch.await(20, TimeUnit.SECONDS)) {
+      logger
+          .info(
+              "Waited for all threads to start, but timed out. We had {} failures.",
+              failureCounter);
+    }
+  }
+
+  @Test
+  public void testOfferShuffle() throws InterruptedException {
+    int testIterations = 10;
+    final CountDownLatch latch = new CountDownLatch(testIterations);
+    final AtomicInteger failureCounter = new AtomicInteger();
+    List<Thread> threads = new ArrayList<Thread>(testIterations);
+
+    for (int i = 1; i <= testIterations; i++) {
+      threads.add(runElectionSupportThread(latch, failureCounter,
+          Math.min(i * 1200, 10000)));
+    }
+
+    if (!latch.await(60, TimeUnit.SECONDS)) {
+      logger
+          .info(
+              "Waited for all threads to start, but timed out. We had {} failures.",
+              failureCounter);
+    }
+  }
+
+  @Test
+  public void testGetLeaderHostName() throws KeeperException,
+      InterruptedException {
+
+    LeaderElectionSupport electionSupport = createLeaderElectionSupport();
+
+    electionSupport.start();
+
+    // Sketchy: We assume there will be a leader (probably us) in 3 seconds.
+    Thread.sleep(3000);
+
+    String leaderHostName = electionSupport.getLeaderHostName();
+
+    Assert.assertNotNull(leaderHostName);
+    Assert.assertEquals("foohost", leaderHostName);
+
+    electionSupport.stop();
+  }
+
+  private LeaderElectionSupport createLeaderElectionSupport() {
+    LeaderElectionSupport electionSupport = new LeaderElectionSupport();
+
+    electionSupport.setZooKeeper(zooKeeper);
+    electionSupport.setRootNodeName(testRootNode
+        + Thread.currentThread().getId());
+    electionSupport.setHostName("foohost");
+
+    return electionSupport;
+  }
+
+  private Thread runElectionSupportThread(final CountDownLatch latch,
+      final AtomicInteger failureCounter) {
+    return runElectionSupportThread(latch, failureCounter, 3000);
+  }
+
+  private Thread runElectionSupportThread(final CountDownLatch latch,
+      final AtomicInteger failureCounter, final long sleepDuration) {
+
+    final LeaderElectionSupport electionSupport = createLeaderElectionSupport();
+
+    Thread t = new Thread() {
+
+      @Override
+      public void run() {
+        try {
+          electionSupport.start();
+          Thread.sleep(sleepDuration);
+          electionSupport.stop();
+
+          latch.countDown();
+        } catch (Exception e) {
+          logger.warn("Failed to run leader election due to: {}",
+              e.getMessage());
+          failureCounter.incrementAndGet();
+        }
+      }
+    };
+
+    t.start();
+
+    return t;
+  }
+
+}

http://git-wip-us.apache.org/repos/asf/zookeeper/blob/e5b4b94d/zookeeper-recipes/lock/README.txt
----------------------------------------------------------------------
diff --git a/zookeeper-recipes/lock/README.txt b/zookeeper-recipes/lock/README.txt
new file mode 100644
index 0000000..1fc4fbf
--- /dev/null
+++ b/zookeeper-recipes/lock/README.txt
@@ -0,0 +1,28 @@
+<!--
+   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.
+-->
+
+1) This lock interface recipe implements the lock recipe
+mentioned in ../../../docs/recipes.[html,pdf].
+
+2) To compile the lock java recipe you can just run ant jar from 
+this directory. For compiling the c libarary go to src/c and read
+the INSTALLATION instructions. 
+Please report any bugs on the jira 
+
+http://issues.apache.org/jira/browse/ZOOKEEPER
+
+  

http://git-wip-us.apache.org/repos/asf/zookeeper/blob/e5b4b94d/zookeeper-recipes/lock/build.xml
----------------------------------------------------------------------
diff --git a/zookeeper-recipes/lock/build.xml b/zookeeper-recipes/lock/build.xml
new file mode 100644
index 0000000..841cc01
--- /dev/null
+++ b/zookeeper-recipes/lock/build.xml
@@ -0,0 +1,128 @@
+<!--
+   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.
+-->
+
+<project name="lock" default="jar">
+  <import file="../build-recipes.xml"/>
+    <property name="test.main.classes" value="${zk.root}/build/test/classes"/>
+    <property name="test.build.dir" value="${build.test}" />
+    <property name="test.src.dir" value="test"/>
+    <property name="test.log.dir" value="${test.build.dir}/logs" />
+    <property name="test.data.dir" value="${test.build.dir}/data" />
+    <property name="test.data.upgrade.dir" value="${test.data.dir}/upgrade" />
+    <property name="test.tmp.dir" value="${test.build.dir}/tmp" />
+    <property name="test.output" value="no" />
+    <property name="test.timeout" value="900000" />
+    <property name="test.junit.output.format" value="plain" />
+    <property name="test.junit.fork.mode" value="perTest" />
+    <property name="test.junit.printsummary" value="yes" />
+    <property name="test.junit.haltonfailure" value="no" />
+    <property name="test.junit.maxmem" value="512m" />
+
+  <target name="setjarname">
+    <property name="jarname"
+              value="${build.dir}/zookeeper-${version}-recipes-${name}.jar"/>
+  </target>
+
+  <!-- Override jar target to specify main class -->
+  <target name="jar" depends="checkMainCompiled, setjarname, compile">
+    <echo message="recipes: ${name}"/>
+
+    <jar jarfile="${jarname}">
+      <fileset file="${zk.root}/LICENSE.txt" />
+      <fileset dir="${build.classes}"/>
+      <fileset dir="${build.test}"/>
+    </jar>
+  </target>
+
+	<target name="test" depends="compile-test,test-init,test-category,junit.run" />
+
+	<target name="compile-test" depends="compile">
+  		<property name="target.jdk" value="${ant.java.version}" />	
+		<property name="src.test.local" location="${basedir}/test" />
+		<mkdir dir="${build.test}"/>
+		<javac srcdir="${src.test.local}" 
+			destdir="${build.test}" 
+			target="${target.jdk}" 
+			debug="on" >
+			<classpath refid="classpath" />
+                        <classpath>
+                        <pathelement path="${test.main.classes}"/>
+                        </classpath>
+		</javac>
+	</target>
+	
+    <target name="test-init" depends="jar,compile-test">
+        <delete dir="${test.log.dir}" />
+        <delete dir="${test.tmp.dir}" />
+        <delete dir="${test.data.dir}" />
+        <mkdir dir="${test.log.dir}" />
+        <mkdir dir="${test.tmp.dir}" />
+        <mkdir dir="${test.data.dir}" />
+    </target>
+
+	<target name="test-category">
+         <property name="test.category" value=""/>
+    </target>
+
+	<target name="junit.run">
+		<echo message="${test.src.dir}" />
+        <junit showoutput="${test.output}"
+               printsummary="${test.junit.printsummary}"
+               haltonfailure="${test.junit.haltonfailure}"
+               fork="yes"
+               forkmode="${test.junit.fork.mode}"
+               maxmemory="${test.junit.maxmem}"
+               dir="${basedir}" timeout="${test.timeout}"
+               errorProperty="tests.failed" failureProperty="tests.failed">
+          <sysproperty key="build.test.dir" value="${test.tmp.dir}" />
+          <sysproperty key="test.data.dir" value="${test.data.dir}" />
+          <sysproperty key="log4j.configuration"
+                    value="file:${basedir}/conf/log4j.properties" />
+          <classpath refid="classpath"/>
+          <classpath>
+             <pathelement path="${build.test}" />
+             <pathelement path="${test.main.classes}"/>
+          </classpath>
+          <formatter type="${test.junit.output.format}" />
+          <batchtest todir="${test.log.dir}" unless="testcase">
+              <fileset dir="${test.src.dir}"
+                     includes="**/*${test.category}Test.java"/>
+          </batchtest>
+          <batchtest todir="${test.log.dir}" if="testcase">
+              <fileset dir="${test.src.dir}" includes="**/${testcase}.java"/>
+          </batchtest>
+       </junit>
+            <fail if="tests.failed">Tests failed!</fail>
+    </target>
+
+  <target name="package" depends="jar, zookeeperbuildrecipes.package"
+          unless="skip.recipes">
+
+    <copy file="${basedir}/build.xml" todir="${dist.dir}${package.share}/recipes/${name}"/>
+
+    <mkdir dir="${dist.dir}${package.share}/recipes/${name}/test"/>
+    <copy todir="${dist.dir}${package.share}/recipes/${name}/test">
+      <fileset dir="${basedir}/test"/>
+    </copy>
+    <mkdir dir="${dist.dir}${package.share}/recipes/${name}/src"/>
+    <copy todir="${dist.dir}${package.share}/recipes/${name}/src">
+      <fileset dir="${basedir}/src"/>
+    </copy>
+  </target>
+
+</project>
+

http://git-wip-us.apache.org/repos/asf/zookeeper/blob/e5b4b94d/zookeeper-recipes/lock/src/c/INSTALL
----------------------------------------------------------------------
diff --git a/zookeeper-recipes/lock/src/c/INSTALL b/zookeeper-recipes/lock/src/c/INSTALL
new file mode 100644
index 0000000..5458714
--- /dev/null
+++ b/zookeeper-recipes/lock/src/c/INSTALL
@@ -0,0 +1,234 @@
+Installation Instructions
+*************************
+
+Copyright (C) 1994, 1995, 1996, 1999, 2000, 2001, 2002, 2004, 2005,
+2006 Free Software Foundation, Inc.
+
+This file is free documentation; the Free Software Foundation gives
+unlimited permission to copy, distribute and modify it.
+
+Basic Installation
+==================
+
+Briefly, the shell commands `./configure; make; make install' should
+configure, build, and install this package.  The following
+more-detailed instructions are generic; see the `README' file for
+instructions specific to this package.
+
+   The `configure' shell script attempts to guess correct values for
+various system-dependent variables used during compilation.  It uses
+those values to create a `Makefile' in each directory of the package.
+It may also create one or more `.h' files containing system-dependent
+definitions.  Finally, it creates a shell script `config.status' that
+you can run in the future to recreate the current configuration, and a
+file `config.log' containing compiler output (useful mainly for
+debugging `configure').
+
+   It can also use an optional file (typically called `config.cache'
+and enabled with `--cache-file=config.cache' or simply `-C') that saves
+the results of its tests to speed up reconfiguring.  Caching is
+disabled by default to prevent problems with accidental use of stale
+cache files.
+
+   If you need to do unusual things to compile the package, please try
+to figure out how `configure' could check whether to do them, and mail
+diffs or instructions to the address given in the `README' so they can
+be considered for the next release.  If you are using the cache, and at
+some point `config.cache' contains results you don't want to keep, you
+may remove or edit it.
+
+   The file `configure.ac' (or `configure.in') is used to create
+`configure' by a program called `autoconf'.  You need `configure.ac' if
+you want to change it or regenerate `configure' using a newer version
+of `autoconf'.
+
+The simplest way to compile this package is:
+
+  1. `cd' to the directory containing the package's source code and type
+     `./configure' to configure the package for your system.
+
+     Running `configure' might take a while.  While running, it prints
+     some messages telling which features it is checking for.
+
+  2. Type `make' to compile the package.
+
+  3. Optionally, type `make check' to run any self-tests that come with
+     the package.
+
+  4. Type `make install' to install the programs and any data files and
+     documentation.
+
+  5. You can remove the program binaries and object files from the
+     source code directory by typing `make clean'.  To also remove the
+     files that `configure' created (so you can compile the package for
+     a different kind of computer), type `make distclean'.  There is
+     also a `make maintainer-clean' target, but that is intended mainly
+     for the package's developers.  If you use it, you may have to get
+     all sorts of other programs in order to regenerate files that came
+     with the distribution.
+
+Compilers and Options
+=====================
+
+Some systems require unusual options for compilation or linking that the
+`configure' script does not know about.  Run `./configure --help' for
+details on some of the pertinent environment variables.
+
+   You can give `configure' initial values for configuration parameters
+by setting variables in the command line or in the environment.  Here
+is an example:
+
+     ./configure CC=c99 CFLAGS=-g LIBS=-lposix
+
+   *Note Defining Variables::, for more details.
+
+Compiling For Multiple Architectures
+====================================
+
+You can compile the package for more than one kind of computer at the
+same time, by placing the object files for each architecture in their
+own directory.  To do this, you can use GNU `make'.  `cd' to the
+directory where you want the object files and executables to go and run
+the `configure' script.  `configure' automatically checks for the
+source code in the directory that `configure' is in and in `..'.
+
+   With a non-GNU `make', it is safer to compile the package for one
+architecture at a time in the source code directory.  After you have
+installed the package for one architecture, use `make distclean' before
+reconfiguring for another architecture.
+
+Installation Names
+==================
+
+By default, `make install' installs the package's commands under
+`/usr/local/bin', include files under `/usr/local/include', etc.  You
+can specify an installation prefix other than `/usr/local' by giving
+`configure' the option `--prefix=PREFIX'.
+
+   You can specify separate installation prefixes for
+architecture-specific files and architecture-independent files.  If you
+pass the option `--exec-prefix=PREFIX' to `configure', the package uses
+PREFIX as the prefix for installing programs and libraries.
+Documentation and other data files still use the regular prefix.
+
+   In addition, if you use an unusual directory layout you can give
+options like `--bindir=DIR' to specify different values for particular
+kinds of files.  Run `configure --help' for a list of the directories
+you can set and what kinds of files go in them.
+
+   If the package supports it, you can cause programs to be installed
+with an extra prefix or suffix on their names by giving `configure' the
+option `--program-prefix=PREFIX' or `--program-suffix=SUFFIX'.
+
+Optional Features
+=================
+
+Some packages pay attention to `--enable-FEATURE' options to
+`configure', where FEATURE indicates an optional part of the package.
+They may also pay attention to `--with-PACKAGE' options, where PACKAGE
+is something like `gnu-as' or `x' (for the X Window System).  The
+`README' should mention any `--enable-' and `--with-' options that the
+package recognizes.
+
+   For packages that use the X Window System, `configure' can usually
+find the X include and library files automatically, but if it doesn't,
+you can use the `configure' options `--x-includes=DIR' and
+`--x-libraries=DIR' to specify their locations.
+
+Specifying the System Type
+==========================
+
+There may be some features `configure' cannot figure out automatically,
+but needs to determine by the type of machine the package will run on.
+Usually, assuming the package is built to be run on the _same_
+architectures, `configure' can figure that out, but if it prints a
+message saying it cannot guess the machine type, give it the
+`--build=TYPE' option.  TYPE can either be a short name for the system
+type, such as `sun4', or a canonical name which has the form:
+
+     CPU-COMPANY-SYSTEM
+
+where SYSTEM can have one of these forms:
+
+     OS KERNEL-OS
+
+   See the file `config.sub' for the possible values of each field.  If
+`config.sub' isn't included in this package, then this package doesn't
+need to know the machine type.
+
+   If you are _building_ compiler tools for cross-compiling, you should
+use the option `--target=TYPE' to select the type of system they will
+produce code for.
+
+   If you want to _use_ a cross compiler, that generates code for a
+platform different from the build platform, you should specify the
+"host" platform (i.e., that on which the generated programs will
+eventually be run) with `--host=TYPE'.
+
+Sharing Defaults
+================
+
+If you want to set default values for `configure' scripts to share, you
+can create a site shell script called `config.site' that gives default
+values for variables like `CC', `cache_file', and `prefix'.
+`configure' looks for `PREFIX/share/config.site' if it exists, then
+`PREFIX/etc/config.site' if it exists.  Or, you can set the
+`CONFIG_SITE' environment variable to the location of the site script.
+A warning: not all `configure' scripts look for a site script.
+
+Defining Variables
+==================
+
+Variables not defined in a site shell script can be set in the
+environment passed to `configure'.  However, some packages may run
+configure again during the build, and the customized values of these
+variables may be lost.  In order to avoid this problem, you should set
+them in the `configure' command line, using `VAR=value'.  For example:
+
+     ./configure CC=/usr/local2/bin/gcc
+
+causes the specified `gcc' to be used as the C compiler (unless it is
+overridden in the site shell script).
+
+Unfortunately, this technique does not work for `CONFIG_SHELL' due to
+an Autoconf bug.  Until the bug is fixed you can use this workaround:
+
+     CONFIG_SHELL=/bin/bash /bin/bash ./configure CONFIG_SHELL=/bin/bash
+
+`configure' Invocation
+======================
+
+`configure' recognizes the following options to control how it operates.
+
+`--help'
+`-h'
+     Print a summary of the options to `configure', and exit.
+
+`--version'
+`-V'
+     Print the version of Autoconf used to generate the `configure'
+     script, and exit.
+
+`--cache-file=FILE'
+     Enable the cache: use and save the results of the tests in FILE,
+     traditionally `config.cache'.  FILE defaults to `/dev/null' to
+     disable caching.
+
+`--config-cache'
+`-C'
+     Alias for `--cache-file=config.cache'.
+
+`--quiet'
+`--silent'
+`-q'
+     Do not print messages saying which checks are being made.  To
+     suppress all normal output, redirect it to `/dev/null' (any error
+     messages will still be shown).
+
+`--srcdir=DIR'
+     Look for the package's source code in directory DIR.  Usually
+     `configure' can determine that directory automatically.
+
+`configure' also accepts some other, not widely useful, options.  Run
+`configure --help' for more details.
+

http://git-wip-us.apache.org/repos/asf/zookeeper/blob/e5b4b94d/zookeeper-recipes/lock/src/c/LICENSE
----------------------------------------------------------------------
diff --git a/zookeeper-recipes/lock/src/c/LICENSE b/zookeeper-recipes/lock/src/c/LICENSE
new file mode 100644
index 0000000..d645695
--- /dev/null
+++ b/zookeeper-recipes/lock/src/c/LICENSE
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   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.

http://git-wip-us.apache.org/repos/asf/zookeeper/blob/e5b4b94d/zookeeper-recipes/lock/src/c/Makefile.am
----------------------------------------------------------------------
diff --git a/zookeeper-recipes/lock/src/c/Makefile.am b/zookeeper-recipes/lock/src/c/Makefile.am
new file mode 100644
index 0000000..9b36b43
--- /dev/null
+++ b/zookeeper-recipes/lock/src/c/Makefile.am
@@ -0,0 +1,46 @@
+# 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.
+
+include $(top_srcdir)/aminclude.am
+
+AM_CFLAGS = -Wall -fPIC -I${ZOOKEEPER_PATH}/include -I${ZOOKEEPER_PATH}/generated \
+  -I$(top_srcdir)/include -I/usr/include 
+AM_CPPFLAGS = -Wall -I${ZOOKEEPER_PATH}/include -I${ZOOKEEPER_PATH}/generated\
+  -I${top_srcdir}/include -I/usr/include
+EXTRA_DIST = LICENSE
+lib_LTLIBRARIES = libzoolock.la
+libzoolock_la_SOURCES = src/zoo_lock.c include/zoo_lock.h
+libzoolock_la_CPPFLAGS = -DDLOPEN_MODULE
+libzoolock_la_LDFLAGS = -version-info 0:1:0
+
+#run the tests now
+
+TEST_SOURCES = tests/TestDriver.cc tests/TestClient.cc tests/Util.cc 
+
+
+check_PROGRAMS = zklocktest
+nodist_zklocktest_SOURCES = ${TEST_SOURCES}
+zklocktest_LDADD =  ${ZOOKEEPER_LD} libzoolock.la -lpthread  ${CPPUNIT_LIBS}
+zklocktest_CXXFLAGS = -DUSE_STATIC_LIB ${CPPUNIT_CFLAGS}
+
+run-check: check
+	./zklocktest ${TEST_OPTIONS}
+
+clean-local: clean-check
+	${RM} ${DX_CLEANFILES}
+
+clean-check:
+	${RM} ${nodist_zklocktest_OBJECTS} 

http://git-wip-us.apache.org/repos/asf/zookeeper/blob/e5b4b94d/zookeeper-recipes/lock/src/c/README.txt
----------------------------------------------------------------------
diff --git a/zookeeper-recipes/lock/src/c/README.txt b/zookeeper-recipes/lock/src/c/README.txt
new file mode 100644
index 0000000..326bba8
--- /dev/null
+++ b/zookeeper-recipes/lock/src/c/README.txt
@@ -0,0 +1,28 @@
+                     Zookeeper C lock client library 
+
+
+INSTALLATION
+
+If you're building the client from a source checkout you need to
+follow the steps outlined below. If you're building from a release
+tar downloaded from Apache please skip to step 2.
+
+1) make sure that you compile the main zookeeper c client library.
+ 
+2) change directory to src/recipes/lock/src/c 
+    and do a "autoreconf -if" to bootstrap
+   autoconf, automake and libtool. Please make sure you have autoconf
+   version 2.59 or greater installed.
+3) do a "./configure [OPTIONS]" to generate the makefile. See INSTALL
+   for general information about running configure.
+
+4) do a "make" or "make install" to build the libraries and install them. 
+   Alternatively, you can also build and run a unit test suite (and
+   you probably should).  Please make sure you have cppunit-1.10.x or
+   higher installed before you execute step 4.  Once ./configure has
+   finished, do a "make run-check". It will build the libraries, build
+   the tests and run them.
+5) to generate doxygen documentation do a "make doxygen-doc". All
+   documentations will be placed to a new subfolder named docs. By
+   default only HTML documentation is generated.  For information on
+   other document formats please use "./configure --help"

http://git-wip-us.apache.org/repos/asf/zookeeper/blob/e5b4b94d/zookeeper-recipes/lock/src/c/acinclude.m4
----------------------------------------------------------------------
diff --git a/zookeeper-recipes/lock/src/c/acinclude.m4 b/zookeeper-recipes/lock/src/c/acinclude.m4
new file mode 100644
index 0000000..d0041d8
--- /dev/null
+++ b/zookeeper-recipes/lock/src/c/acinclude.m4
@@ -0,0 +1,312 @@
+# This file is part of Autoconf.                       -*- Autoconf -*-
+
+# Copyright (C) 2004 Oren Ben-Kiki
+# This file is distributed under the same terms as the Autoconf macro files.
+
+# Generate automatic documentation using Doxygen. Works in concert with the
+# aminclude.m4 file and a compatible doxygen configuration file. Defines the
+# following public macros:
+#
+# DX_???_FEATURE(ON|OFF) - control the default setting fo a Doxygen feature.
+# Supported features are 'DOXYGEN' itself, 'DOT' for generating graphics,
+# 'HTML' for plain HTML, 'CHM' for compressed HTML help (for MS users), 'CHI'
+# for generating a seperate .chi file by the .chm file, and 'MAN', 'RTF',
+# 'XML', 'PDF' and 'PS' for the appropriate output formats. The environment
+# variable DOXYGEN_PAPER_SIZE may be specified to override the default 'a4wide'
+# paper size.
+#
+# By default, HTML, PDF and PS documentation is generated as this seems to be
+# the most popular and portable combination. MAN pages created by Doxygen are
+# usually problematic, though by picking an appropriate subset and doing some
+# massaging they might be better than nothing. CHM and RTF are specific for MS
+# (note that you can't generate both HTML and CHM at the same time). The XML is
+# rather useless unless you apply specialized post-processing to it.
+#
+# The macro mainly controls the default state of the feature. The use can
+# override the default by specifying --enable or --disable. The macros ensure
+# that contradictory flags are not given (e.g., --enable-doxygen-html and
+# --enable-doxygen-chm, --enable-doxygen-anything with --disable-doxygen, etc.)
+# Finally, each feature will be automatically disabled (with a warning) if the
+# required programs are missing.
+#
+# Once all the feature defaults have been specified, call DX_INIT_DOXYGEN with
+# the following parameters: a one-word name for the project for use as a
+# filename base etc., an optional configuration file name (the default is
+# 'Doxyfile', the same as Doxygen's default), and an optional output directory
+# name (the default is 'doxygen-doc').
+
+## ----------##
+## Defaults. ##
+## ----------##
+
+DX_ENV=""
+AC_DEFUN([DX_FEATURE_doc],  ON)
+AC_DEFUN([DX_FEATURE_dot],  ON)
+AC_DEFUN([DX_FEATURE_man],  OFF)
+AC_DEFUN([DX_FEATURE_html], ON)
+AC_DEFUN([DX_FEATURE_chm],  OFF)
+AC_DEFUN([DX_FEATURE_chi],  OFF)
+AC_DEFUN([DX_FEATURE_rtf],  OFF)
+AC_DEFUN([DX_FEATURE_xml],  OFF)
+AC_DEFUN([DX_FEATURE_pdf],  ON)
+AC_DEFUN([DX_FEATURE_ps],   ON)
+
+## --------------- ##
+## Private macros. ##
+## --------------- ##
+
+# DX_ENV_APPEND(VARIABLE, VALUE)
+# ------------------------------
+# Append VARIABLE="VALUE" to DX_ENV for invoking doxygen.
+AC_DEFUN([DX_ENV_APPEND], [AC_SUBST([DX_ENV], ["$DX_ENV $1='$2'"])])
+
+# DX_DIRNAME_EXPR
+# ---------------
+# Expand into a shell expression prints the directory part of a path.
+AC_DEFUN([DX_DIRNAME_EXPR],
+         [[expr ".$1" : '\(\.\)[^/]*$' \| "x$1" : 'x\(.*\)/[^/]*$']])
+
+# DX_IF_FEATURE(FEATURE, IF-ON, IF-OFF)
+# -------------------------------------
+# Expands according to the M4 (static) status of the feature.
+AC_DEFUN([DX_IF_FEATURE], [ifelse(DX_FEATURE_$1, ON, [$2], [$3])])
+
+# DX_REQUIRE_PROG(VARIABLE, PROGRAM)
+# ----------------------------------
+# Require the specified program to be found for the DX_CURRENT_FEATURE to work.
+AC_DEFUN([DX_REQUIRE_PROG], [
+AC_PATH_TOOL([$1], [$2])
+if test "$DX_FLAG_$[DX_CURRENT_FEATURE$$1]" = 1; then
+    AC_MSG_WARN([$2 not found - will not DX_CURRENT_DESCRIPTION])
+    AC_SUBST([DX_FLAG_]DX_CURRENT_FEATURE, 0)
+fi
+])
+
+# DX_TEST_FEATURE(FEATURE)
+# ------------------------
+# Expand to a shell expression testing whether the feature is active.
+AC_DEFUN([DX_TEST_FEATURE], [test "$DX_FLAG_$1" = 1])
+
+# DX_CHECK_DEPEND(REQUIRED_FEATURE, REQUIRED_STATE)
+# -------------------------------------------------
+# Verify that a required features has the right state before trying to turn on
+# the DX_CURRENT_FEATURE.
+AC_DEFUN([DX_CHECK_DEPEND], [
+test "$DX_FLAG_$1" = "$2" \
+|| AC_MSG_ERROR([doxygen-DX_CURRENT_FEATURE ifelse([$2], 1,
+                            requires, contradicts) doxygen-DX_CURRENT_FEATURE])
+])
+
+# DX_CLEAR_DEPEND(FEATURE, REQUIRED_FEATURE, REQUIRED_STATE)
+# ----------------------------------------------------------
+# Turn off the DX_CURRENT_FEATURE if the required feature is off.
+AC_DEFUN([DX_CLEAR_DEPEND], [
+test "$DX_FLAG_$1" = "$2" || AC_SUBST([DX_FLAG_]DX_CURRENT_FEATURE, 0)
+])
+
+# DX_FEATURE_ARG(FEATURE, DESCRIPTION,
+#                CHECK_DEPEND, CLEAR_DEPEND,
+#                REQUIRE, DO-IF-ON, DO-IF-OFF)
+# --------------------------------------------
+# Parse the command-line option controlling a feature. CHECK_DEPEND is called
+# if the user explicitly turns the feature on (and invokes DX_CHECK_DEPEND),
+# otherwise CLEAR_DEPEND is called to turn off the default state if a required
+# feature is disabled (using DX_CLEAR_DEPEND). REQUIRE performs additional
+# requirement tests (DX_REQUIRE_PROG). Finally, an automake flag is set and
+# DO-IF-ON or DO-IF-OFF are called according to the final state of the feature.
+AC_DEFUN([DX_ARG_ABLE], [
+    AC_DEFUN([DX_CURRENT_FEATURE], [$1])
+    AC_DEFUN([DX_CURRENT_DESCRIPTION], [$2])
+    AC_ARG_ENABLE(doxygen-$1,
+                  [AS_HELP_STRING(DX_IF_FEATURE([$1], [--disable-doxygen-$1],
+                                                      [--enable-doxygen-$1]),
+                                  DX_IF_FEATURE([$1], [don't $2], [$2]))],
+                  [
+case "$enableval" in
+#(
+y|Y|yes|Yes|YES)
+    AC_SUBST([DX_FLAG_$1], 1)
+    $3
+;; #(
+n|N|no|No|NO)
+    AC_SUBST([DX_FLAG_$1], 0)
+;; #(
+*)
+    AC_MSG_ERROR([invalid value '$enableval' given to doxygen-$1])
+;;
+esac
+], [
+AC_SUBST([DX_FLAG_$1], [DX_IF_FEATURE([$1], 1, 0)])
+$4
+])
+if DX_TEST_FEATURE([$1]); then
+    $5
+    :
+fi
+if DX_TEST_FEATURE([$1]); then
+    AM_CONDITIONAL(DX_COND_$1, :)
+    $6
+    :
+else
+    AM_CONDITIONAL(DX_COND_$1, false)
+    $7
+    :
+fi
+])
+
+## -------------- ##
+## Public macros. ##
+## -------------- ##
+
+# DX_XXX_FEATURE(DEFAULT_STATE)
+# -----------------------------
+AC_DEFUN([DX_DOXYGEN_FEATURE], [AC_DEFUN([DX_FEATURE_doc],  [$1])])
+AC_DEFUN([DX_MAN_FEATURE],     [AC_DEFUN([DX_FEATURE_man],  [$1])])
+AC_DEFUN([DX_HTML_FEATURE],    [AC_DEFUN([DX_FEATURE_html], [$1])])
+AC_DEFUN([DX_CHM_FEATURE],     [AC_DEFUN([DX_FEATURE_chm],  [$1])])
+AC_DEFUN([DX_CHI_FEATURE],     [AC_DEFUN([DX_FEATURE_chi],  [$1])])
+AC_DEFUN([DX_RTF_FEATURE],     [AC_DEFUN([DX_FEATURE_rtf],  [$1])])
+AC_DEFUN([DX_XML_FEATURE],     [AC_DEFUN([DX_FEATURE_xml],  [$1])])
+AC_DEFUN([DX_XML_FEATURE],     [AC_DEFUN([DX_FEATURE_xml],  [$1])])
+AC_DEFUN([DX_PDF_FEATURE],     [AC_DEFUN([DX_FEATURE_pdf],  [$1])])
+AC_DEFUN([DX_PS_FEATURE],      [AC_DEFUN([DX_FEATURE_ps],   [$1])])
+
+# DX_INIT_DOXYGEN(PROJECT, [CONFIG-FILE], [OUTPUT-DOC-DIR])
+# ---------------------------------------------------------
+# PROJECT also serves as the base name for the documentation files.
+# The default CONFIG-FILE is "Doxyfile" and OUTPUT-DOC-DIR is "doxygen-doc".
+AC_DEFUN([DX_INIT_DOXYGEN], [
+
+# Files:
+AC_SUBST([DX_PROJECT], [$1])
+AC_SUBST([DX_CONFIG], [ifelse([$2], [], Doxyfile, [$2])])
+AC_SUBST([DX_DOCDIR], [ifelse([$3], [], doxygen-doc, [$3])])
+
+# Environment variables used inside doxygen.cfg:
+DX_ENV_APPEND(SRCDIR, $srcdir)
+DX_ENV_APPEND(PROJECT, $DX_PROJECT)
+DX_ENV_APPEND(DOCDIR, $DX_DOCDIR)
+DX_ENV_APPEND(VERSION, $PACKAGE_VERSION)
+
+# Doxygen itself:
+DX_ARG_ABLE(doc, [generate any doxygen documentation],
+            [],
+            [],
+            [DX_REQUIRE_PROG([DX_DOXYGEN], doxygen)
+             DX_REQUIRE_PROG([DX_PERL], perl)],
+            [DX_ENV_APPEND(PERL_PATH, $DX_PERL)])
+
+# Dot for graphics:
+DX_ARG_ABLE(dot, [generate graphics for doxygen documentation],
+            [DX_CHECK_DEPEND(doc, 1)],
+            [DX_CLEAR_DEPEND(doc, 1)],
+            [DX_REQUIRE_PROG([DX_DOT], dot)],
+            [DX_ENV_APPEND(HAVE_DOT, YES)
+             DX_ENV_APPEND(DOT_PATH, [`DX_DIRNAME_EXPR($DX_DOT)`])],
+            [DX_ENV_APPEND(HAVE_DOT, NO)])
+
+# Man pages generation:
+DX_ARG_ABLE(man, [generate doxygen manual pages],
+            [DX_CHECK_DEPEND(doc, 1)],
+            [DX_CLEAR_DEPEND(doc, 1)],
+            [],
+            [DX_ENV_APPEND(GENERATE_MAN, YES)],
+            [DX_ENV_APPEND(GENERATE_MAN, NO)])
+
+# RTF file generation:
+DX_ARG_ABLE(rtf, [generate doxygen RTF documentation],
+            [DX_CHECK_DEPEND(doc, 1)],
+            [DX_CLEAR_DEPEND(doc, 1)],
+            [],
+            [DX_ENV_APPEND(GENERATE_RTF, YES)],
+            [DX_ENV_APPEND(GENERATE_RTF, NO)])
+
+# XML file generation:
+DX_ARG_ABLE(xml, [generate doxygen XML documentation],
+            [DX_CHECK_DEPEND(doc, 1)],
+            [DX_CLEAR_DEPEND(doc, 1)],
+            [],
+            [DX_ENV_APPEND(GENERATE_XML, YES)],
+            [DX_ENV_APPEND(GENERATE_XML, NO)])
+
+# (Compressed) HTML help generation:
+DX_ARG_ABLE(chm, [generate doxygen compressed HTML help documentation],
+            [DX_CHECK_DEPEND(doc, 1)],
+            [DX_CLEAR_DEPEND(doc, 1)],
+            [DX_REQUIRE_PROG([DX_HHC], hhc)],
+            [DX_ENV_APPEND(HHC_PATH, $DX_HHC)
+             DX_ENV_APPEND(GENERATE_HTML, YES)
+             DX_ENV_APPEND(GENERATE_HTMLHELP, YES)],
+            [DX_ENV_APPEND(GENERATE_HTMLHELP, NO)])
+
+# Seperate CHI file generation.
+DX_ARG_ABLE(chi, [generate doxygen seperate compressed HTML help index file],
+            [DX_CHECK_DEPEND(chm, 1)],
+            [DX_CLEAR_DEPEND(chm, 1)],
+            [],
+            [DX_ENV_APPEND(GENERATE_CHI, YES)],
+            [DX_ENV_APPEND(GENERATE_CHI, NO)])
+
+# Plain HTML pages generation:
+DX_ARG_ABLE(html, [generate doxygen plain HTML documentation],
+            [DX_CHECK_DEPEND(doc, 1) DX_CHECK_DEPEND(chm, 0)],
+            [DX_CLEAR_DEPEND(doc, 1) DX_CLEAR_DEPEND(chm, 0)],
+            [],
+            [DX_ENV_APPEND(GENERATE_HTML, YES)],
+            [DX_TEST_FEATURE(chm) || DX_ENV_APPEND(GENERATE_HTML, NO)])
+
+# PostScript file generation:
+DX_ARG_ABLE(ps, [generate doxygen PostScript documentation],
+            [DX_CHECK_DEPEND(doc, 1)],
+            [DX_CLEAR_DEPEND(doc, 1)],
+            [DX_REQUIRE_PROG([DX_LATEX], latex)
+             DX_REQUIRE_PROG([DX_MAKEINDEX], makeindex)
+             DX_REQUIRE_PROG([DX_DVIPS], dvips)
+             DX_REQUIRE_PROG([DX_EGREP], egrep)])
+
+# PDF file generation:
+DX_ARG_ABLE(pdf, [generate doxygen PDF documentation],
+            [DX_CHECK_DEPEND(doc, 1)],
+            [DX_CLEAR_DEPEND(doc, 1)],
+            [DX_REQUIRE_PROG([DX_PDFLATEX], pdflatex)
+             DX_REQUIRE_PROG([DX_MAKEINDEX], makeindex)
+             DX_REQUIRE_PROG([DX_EGREP], egrep)])
+
+# LaTeX generation for PS and/or PDF:
+if DX_TEST_FEATURE(ps) || DX_TEST_FEATURE(pdf); then
+    AM_CONDITIONAL(DX_COND_latex, :)
+    DX_ENV_APPEND(GENERATE_LATEX, YES)
+else
+    AM_CONDITIONAL(DX_COND_latex, false)
+    DX_ENV_APPEND(GENERATE_LATEX, NO)
+fi
+
+# Paper size for PS and/or PDF:
+AC_ARG_VAR(DOXYGEN_PAPER_SIZE,
+           [a4wide (default), a4, letter, legal or executive])
+case "$DOXYGEN_PAPER_SIZE" in
+#(
+"")
+    AC_SUBST(DOXYGEN_PAPER_SIZE, "")
+;; #(
+a4wide|a4|letter|legal|executive)
+    DX_ENV_APPEND(PAPER_SIZE, $DOXYGEN_PAPER_SIZE)
+;; #(
+*)
+    AC_MSG_ERROR([unknown DOXYGEN_PAPER_SIZE='$DOXYGEN_PAPER_SIZE'])
+;;
+esac
+
+#For debugging:
+#echo DX_FLAG_doc=$DX_FLAG_doc
+#echo DX_FLAG_dot=$DX_FLAG_dot
+#echo DX_FLAG_man=$DX_FLAG_man
+#echo DX_FLAG_html=$DX_FLAG_html
+#echo DX_FLAG_chm=$DX_FLAG_chm
+#echo DX_FLAG_chi=$DX_FLAG_chi
+#echo DX_FLAG_rtf=$DX_FLAG_rtf
+#echo DX_FLAG_xml=$DX_FLAG_xml
+#echo DX_FLAG_pdf=$DX_FLAG_pdf
+#echo DX_FLAG_ps=$DX_FLAG_ps
+#echo DX_ENV=$DX_ENV
+])

http://git-wip-us.apache.org/repos/asf/zookeeper/blob/e5b4b94d/zookeeper-recipes/lock/src/c/aminclude.am
----------------------------------------------------------------------
diff --git a/zookeeper-recipes/lock/src/c/aminclude.am b/zookeeper-recipes/lock/src/c/aminclude.am
new file mode 100644
index 0000000..420049e
--- /dev/null
+++ b/zookeeper-recipes/lock/src/c/aminclude.am
@@ -0,0 +1,186 @@
+# Copyright (C) 2004 Oren Ben-Kiki
+# This file is distributed under the same terms as the Automake macro files.
+
+# Generate automatic documentation using Doxygen. Goals and variables values
+# are controlled by the various DX_COND_??? conditionals set by autoconf.
+#
+# The provided goals are:
+# doxygen-doc: Generate all doxygen documentation.
+# doxygen-run: Run doxygen, which will generate some of the documentation
+#              (HTML, CHM, CHI, MAN, RTF, XML) but will not do the post
+#              processing required for the rest of it (PS, PDF, and some MAN).
+# doxygen-man: Rename some doxygen generated man pages.
+# doxygen-ps: Generate doxygen PostScript documentation.
+# doxygen-pdf: Generate doxygen PDF documentation.
+#
+# Note that by default these are not integrated into the automake goals. If
+# doxygen is used to generate man pages, you can achieve this integration by
+# setting man3_MANS to the list of man pages generated and then adding the
+# dependency:
+#
+#   $(man3_MANS): doxygen-doc
+#
+# This will cause make to run doxygen and generate all the documentation.
+#
+# The following variable is intended for use in Makefile.am:
+#
+# DX_CLEANFILES = everything to clean.
+#
+# This is usually added to MOSTLYCLEANFILES.
+
+## --------------------------------- ##
+## Format-independent Doxygen rules. ##
+## --------------------------------- ##
+
+if DX_COND_doc
+
+## ------------------------------- ##
+## Rules specific for HTML output. ##
+## ------------------------------- ##
+
+if DX_COND_html
+
+DX_CLEAN_HTML = @DX_DOCDIR@/html
+
+endif DX_COND_html
+
+## ------------------------------ ##
+## Rules specific for CHM output. ##
+## ------------------------------ ##
+
+if DX_COND_chm
+
+DX_CLEAN_CHM = @DX_DOCDIR@/chm
+
+if DX_COND_chi
+
+DX_CLEAN_CHI = @DX_DOCDIR@/@PACKAGE@.chi
+
+endif DX_COND_chi
+
+endif DX_COND_chm
+
+## ------------------------------ ##
+## Rules specific for MAN output. ##
+## ------------------------------ ##
+
+if DX_COND_man
+
+DX_CLEAN_MAN = @DX_DOCDIR@/man
+
+endif DX_COND_man
+
+## ------------------------------ ##
+## Rules specific for RTF output. ##
+## ------------------------------ ##
+
+if DX_COND_rtf
+
+DX_CLEAN_RTF = @DX_DOCDIR@/rtf
+
+endif DX_COND_rtf
+
+## ------------------------------ ##
+## Rules specific for XML output. ##
+## ------------------------------ ##
+
+if DX_COND_xml
+
+DX_CLEAN_XML = @DX_DOCDIR@/xml
+
+endif DX_COND_xml
+
+## ----------------------------- ##
+## Rules specific for PS output. ##
+## ----------------------------- ##
+
+if DX_COND_ps
+
+DX_CLEAN_PS = @DX_DOCDIR@/@PACKAGE@.ps
+
+DX_PS_GOAL = doxygen-ps
+
+doxygen-ps: @DX_DOCDIR@/@PACKAGE@.ps
+
+@DX_DOCDIR@/@PACKAGE@.ps: @DX_DOCDIR@/@PACKAGE@.tag
+	cd @DX_DOCDIR@/latex; \
+	rm -f *.aux *.toc *.idx *.ind *.ilg *.log *.out; \
+	$(DX_LATEX) refman.tex; \
+	$(MAKEINDEX_PATH) refman.idx; \
+	$(DX_LATEX) refman.tex; \
+	countdown=5; \
+	while $(DX_EGREP) 'Rerun (LaTeX|to get cross-references right)' \
+	                  refman.log > /dev/null 2>&1 \
+	   && test $$countdown -gt 0; do \
+	    $(DX_LATEX) refman.tex; \
+	    countdown=`expr $$countdown - 1`; \
+	done; \
+	$(DX_DVIPS) -o ../@PACKAGE@.ps refman.dvi
+
+endif DX_COND_ps
+
+## ------------------------------ ##
+## Rules specific for PDF output. ##
+## ------------------------------ ##
+
+if DX_COND_pdf
+
+DX_CLEAN_PDF = @DX_DOCDIR@/@PACKAGE@.pdf
+
+DX_PDF_GOAL = doxygen-pdf
+
+doxygen-pdf: @DX_DOCDIR@/@PACKAGE@.pdf
+
+@DX_DOCDIR@/@PACKAGE@.pdf: @DX_DOCDIR@/@PACKAGE@.tag
+	cd @DX_DOCDIR@/latex; \
+	rm -f *.aux *.toc *.idx *.ind *.ilg *.log *.out; \
+	$(DX_PDFLATEX) refman.tex; \
+	$(DX_MAKEINDEX) refman.idx; \
+	$(DX_PDFLATEX) refman.tex; \
+	countdown=5; \
+	while $(DX_EGREP) 'Rerun (LaTeX|to get cross-references right)' \
+	                  refman.log > /dev/null 2>&1 \
+	   && test $$countdown -gt 0; do \
+	    $(DX_PDFLATEX) refman.tex; \
+	    countdown=`expr $$countdown - 1`; \
+	done; \
+	mv refman.pdf ../@PACKAGE@.pdf
+
+endif DX_COND_pdf
+
+## ------------------------------------------------- ##
+## Rules specific for LaTeX (shared for PS and PDF). ##
+## ------------------------------------------------- ##
+
+if DX_COND_latex
+
+DX_CLEAN_LATEX = @DX_DOCDIR@/latex
+
+endif DX_COND_latex
+
+.PHONY: doxygen-run doxygen-doc $(DX_PS_GOAL) $(DX_PDF_GOAL)
+
+.INTERMEDIATE: doxygen-run $(DX_PS_GOAL) $(DX_PDF_GOAL)
+
+doxygen-run: @DX_DOCDIR@/@PACKAGE@.tag
+
+doxygen-doc: doxygen-run $(DX_PS_GOAL) $(DX_PDF_GOAL)
+
+@DX_DOCDIR@/@PACKAGE@.tag: $(DX_CONFIG) $(pkginclude_HEADERS)
+	rm -rf @DX_DOCDIR@
+	$(DX_ENV) $(DX_DOXYGEN) $(srcdir)/$(DX_CONFIG)
+
+DX_CLEANFILES = \
+    @DX_DOCDIR@/@PACKAGE@.tag \
+    -r \
+    $(DX_CLEAN_HTML) \
+    $(DX_CLEAN_CHM) \
+    $(DX_CLEAN_CHI) \
+    $(DX_CLEAN_MAN) \
+    $(DX_CLEAN_RTF) \
+    $(DX_CLEAN_XML) \
+    $(DX_CLEAN_PS) \
+    $(DX_CLEAN_PDF) \
+    $(DX_CLEAN_LATEX)
+
+endif DX_COND_doc