[java,zookeeper]2.1 KeeperState.SyncConnected linker

4rrr · 发表于 2015-12-24 11:31:24

1. Watcher1
自身实现 Watcher 接口，传入 this

package org.apache.zookeeper.demo;
import java.util.concurrent.CountDownLatch ;
import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.Watcher.Event.* ;
import org.apache.zookeeper.ZooKeeper ;
/**
* Created by root on 6/28/15.
*/
public class SyncConnect_Event_Tester implements Watcher // Watcher 1
{
ZooKeeper zk = null ;
final String CONNECTION_STRING = "127.0.0.1:2181" ;
final int SESSSION_TIMER = 2000 ;
private CountDownLatch connectedSemaphore = new CountDownLatch( 1 ) ;
public SyncConnect_Event_Tester ()
{
try
{
zk = new ZooKeeper ( CONNECTION_STRING , SESSSION_TIMER , this ) ;
this.connectedSemaphore.await () ;
}
catch ( Exception e )
{
e.printStackTrace();
}
}
public void process ( WatchedEvent we )
{
try
{
Event.KeeperState keeperState = we.getState() ;
System.out.println (we.getState().toString()) ;
if (keeperState == Event.KeeperState.SyncConnected )
{
System.out.println ("[Watche1] success connect to ZooKeeper Server ") ;
connectedSemaphore.countDown();
}
}
catch ( Exception ex )
{
}
}
public static void main ( String [] args )
{
SyncConnect_Event_Tester tester = new SyncConnect_Event_Tester() ;
}
}

2. Watcher2
另创建一个类实现 Watcher，传入该类的实例对象

package org.apache.zookeeper.demo;
import java.util.concurrent.CountDownLatch ;
import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.Watcher.Event.* ;
import org.apache.zookeeper.ZooKeeper ;
/**
* Created by root on 6/28/15.
*/
public class SyncConnect_Event_Tester implements Watcher // Watcher 1
{
ZooKeeper zk = null ;
final String CONNECTION_STRING = "127.0.0.1:2181" ;
final int SESSSION_TIMER = 2000 ;
private CountDownLatch connectedSemaphore = new CountDownLatch( 1 ) ;
public SyncConnect_Event_Tester ()
{
try
{
WatcherLoader w = new WatcherLoader( this.connectedSemaphore ) ;
zk = new ZooKeeper (CONNECTION_STRING , SESSSION_TIMER , w ) ; // this is for the Watcher 2
this.connectedSemaphore.await () ;
}
catch ( Exception e )
{
e.printStackTrace();
}
}
public static void main ( String [] args )
{
SyncConnect_Event_Tester tester = new SyncConnect_Event_Tester() ;
}
}
class WatcherLoader implements Watcher
{
private CountDownLatch countDownLatch ;
public WatcherLoader ( CountDownLatch countDownLatch )
{
this.countDownLatch = countDownLatch ;
}
public void process ( WatchedEvent e) {
try
{
Event.KeeperState keeperState = e.getState() ;
if (keeperState == Event.KeeperState.SyncConnected )
{
System.out.println ("[Watche2] success connect to ZooKeeper Server ") ;
countDownLatch.countDown();
}
}
catch ( Exception ex )
{
// ignore
}
}
}

3. Watcher3

直接在 ZooKeeper 构造方法的 Watcher 参数中创建一个 Watcher 接口实例，并在 Watcher 内部编写 process 方法。

package org.apache.zookeeper.demo;

import java.util.concurrent.CountDownLatch ;

import org.apache.zookeeper.WatchedEvent;

import org.apache.zookeeper.Watcher;

import org.apache.zookeeper.Watcher.Event.* ;

import org.apache.zookeeper.ZooKeeper ;

/**

* Created by root on 6/28/15.

*/

public class SyncConnect_Event_Tester implements Watcher // Watcher 1

{

ZooKeeper zk = null ;

final String CONNECTION_STRING = "127.0.0.1:2181" ;

final int SESSSION_TIMER = 2000 ;

private CountDownLatch connectedSemaphore = new CountDownLatch( 1 ) ;

public SyncConnect_Event_Tester ()

{

      try

      {

         // this is for the Watcher 3

         zk = new ZooKeeper ( CONNECTION_STRING , SESSSION_TIMER , new Watcher ()

         {

            public void process ( WatchedEvent e )

            {

                  try

                  {

                     Event.KeeperState keeperState = e.getState() ;

                     if (keeperState == Event.KeeperState.SyncConnected )

                     {

                        System.out.println ("[Watche3] success connect to ZooKeeper Server ") ;

                        connectedSemaphore.countDown();

                     }

                  }

                  catch ( Exception ex )

                  {

                     // ignored

                  }

            }

         }) ;

         this.connectedSemaphore.await () ;

      }

      catch ( Exception e )

      {

         e.printStackTrace();

      }

}

public static void main ( String [] args )

{

      SyncConnect_Event_Tester tester = new SyncConnect_Event_Tester() ;

}

}

4. Watcher4
类似于第三种方法，创建 Watcher 实例，需要的时候将该实例传入到参数中.

package org.apache.zookeeper.demo;
import java.util.concurrent.CountDownLatch ;
import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.Watcher.Event.* ;
import org.apache.zookeeper.ZooKeeper ;
/**
* Created by root on 6/28/15.
*/
public class SyncConnect_Event_Tester implements Watcher // Watcher 1
{
ZooKeeper zk = null ;
final String CONNECTION_STRING = "127.0.0.1:2181" ;
final int SESSSION_TIMER = 2000 ;
Watcher watcher ;
private CountDownLatch connectedSemaphore = new CountDownLatch( 1 ) ;
public SyncConnect_Event_Tester ()
{
try
{
// this is for the Watcher 4
this.watcher = new Watcher () {
public void process(WatchedEvent e) {
try
{
Event.KeeperState keeperState = e.getState() ;
if (keeperState == Event.KeeperState.SyncConnected )
{
System.out.println ("[Watche4] success connect to ZooKeeper Server ") ;
connectedSemaphore.countDown();
}
}
catch ( Exception ex )
{
// ignored
}
}
} ;
zk = new ZooKeeper (CONNECTION_STRING, SESSSION_TIMER , this.watcher) ;
this.connectedSemaphore.await () ;
}
catch ( Exception e )
{
e.printStackTrace();
}
}
public static void main ( String [] args )
{
SyncConnect_Event_Tester tester = new SyncConnect_Event_Tester() ;
}
}

end

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