Testing if calling ZooKeeper's getData() on the path for updated node returns the updated _data_.

TestZooKeeperGetData.java

package zookeeper.test.getdata;



import static org.junit.Assert.assertTrue;

import org.apache.zookeeper.CreateMode;
import org.apache.zookeeper.ZooDefs.Ids;
import org.apache.zookeeper.ZooKeeper;
import org.apache.zookeeper.data.Stat;
import org.junit.Test;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.netflix.curator.test.TestingServer;

/**
 * Tests if calling getData() on a node that has been changed always returns the updated value.
 * {@link ZooKeeperer} is used to keep track of the value set on the node after watch is fired.
 * 
 * @author Amirhossein Kiani (amirhkiani@gmail.com) Created on Mar 2, 2012
 */
public class TestZooKeeperGetData {
  static final Logger logger = LoggerFactory.getLogger(TestZooKeeperGetData.class);
  private static final int NUMBER_OF_TESTS = 10000;
  
  @Test
  public void testZoo() throws Exception {
    TestingServer testingServer = new TestingServer(12322);
    ZooKeeperer zooKeeperer = new ZooKeeperer();
    ZooKeeper zoo = new ZooKeeper(testingServer.getConnectString(), 1000, zooKeeperer);
    zooKeeperer.setZk(zoo, NUMBER_OF_TESTS);
    Stat stat = new Stat();
    zoo.create("/test", new byte[0], Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);

    for (int a = 0; a < NUMBER_OF_TESTS; a++) {
      zoo.getData("/test", zooKeeperer, stat);
      String string = String.valueOf(a);
      zoo.setData("/test", string.getBytes(), stat.getVersion());
    }

    while(!zooKeeperer.doneWithWatches){
      Thread.sleep(100);
    }
    
    for (int a = 0; a < NUMBER_OF_TESTS; a++) {
      assertTrue("Data " + a + " was never receieved.", zooKeeperer.values[a]);
    }
  }
}

ZooKeeperer.java

package zookeeper.test.getdata;


import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.Watcher.Event.EventType;
import org.apache.zookeeper.ZooKeeper;
import org.apache.zookeeper.data.Stat;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;


/**
 * Keeps track of the values returned after {@link TestZooKeeperGetData} sets data on the "/test"
 * node, by marking each value it receives in a boolean array.
 * 
 * @author Amirhossein Kiani (amirhkiani@gmail.com) Created on Mar 2, 2012
 */
public class ZooKeeperer implements Watcher {
  final static Logger logger = LoggerFactory.getLogger(ZooKeeperer.class);
  private ZooKeeper zk;
  boolean[] values;
  boolean doneWithWatches = false; 
  int numberOfEvents = 0;
  
  public ZooKeeperer() {}

  public void setZk(ZooKeeper zk, int numberOfTests) {
    this.zk = zk;
    this.values = new boolean[numberOfTests];
  }

  public void process(WatchedEvent event) {
    try {
      
      if (event.getType().equals(EventType.NodeDataChanged)) {
        numberOfEvents ++;
        byte[] data = zk.getData(event.getPath(), false, new Stat());
        String dataString = new String(data);

        //convert string to integer
        int number = Integer.valueOf(dataString);
        
        //mark this value as received
        values[number] = true;
        if(numberOfEvents == values.length - 1){
          doneWithWatches = true;
        }
      }
    } catch (Exception e) {
      logger.error("Exception in processing the watch.", e);
    }
  }
}