/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.curator;
import org.apache.curator.ensemble.
EnsembleProvider;
import org.apache.curator.utils.
ZookeeperFactory;
import org.apache.zookeeper.
WatchedEvent;
import org.apache.zookeeper.
Watcher;
import org.apache.zookeeper.
ZooKeeper;
class
HandleHolder
{
private final
ZookeeperFactory zookeeperFactory;
private final
Watcher watcher;
private final
EnsembleProvider ensembleProvider;
private final int
sessionTimeout;
private final boolean
canBeReadOnly;
private volatile
Helper helper;
private interface
Helper
{
ZooKeeper getZooKeeper() throws
Exception;
String getConnectionString();
int
getNegotiatedSessionTimeoutMs();
}
HandleHolder(
ZookeeperFactory zookeeperFactory,
Watcher watcher,
EnsembleProvider ensembleProvider, int
sessionTimeout, boolean
canBeReadOnly)
{
this.
zookeeperFactory =
zookeeperFactory;
this.
watcher =
watcher;
this.
ensembleProvider =
ensembleProvider;
this.
sessionTimeout =
sessionTimeout;
this.
canBeReadOnly =
canBeReadOnly;
}
ZooKeeper getZooKeeper() throws
Exception
{
return (
helper != null) ?
helper.
getZooKeeper() : null;
}
int
getNegotiatedSessionTimeoutMs()
{
return (
helper != null) ?
helper.
getNegotiatedSessionTimeoutMs() : 0;
}
String getConnectionString()
{
return (
helper != null) ?
helper.
getConnectionString() : null;
}
String getNewConnectionString()
{
String helperConnectionString = (
helper != null) ?
helper.
getConnectionString() : null;
return ((
helperConnectionString != null) && !
ensembleProvider.
getConnectionString().
equals(
helperConnectionString)) ?
helperConnectionString : null;
}
void
closeAndClear() throws
Exception
{
internalClose();
helper = null;
}
void
closeAndReset() throws
Exception
{
internalClose();
// first helper is synchronized when getZooKeeper is called. Subsequent calls
// are not synchronized.
helper = new
Helper()
{
private volatile
ZooKeeper zooKeeperHandle = null;
private volatile
String connectionString = null;
@
Override
public
ZooKeeper getZooKeeper() throws
Exception
{
synchronized(this)
{
if (
zooKeeperHandle == null )
{
connectionString =
ensembleProvider.
getConnectionString();
zooKeeperHandle =
zookeeperFactory.
newZooKeeper(
connectionString,
sessionTimeout,
watcher,
canBeReadOnly);
}
helper = new
Helper()
{
@
Override
public
ZooKeeper getZooKeeper() throws
Exception
{
return
zooKeeperHandle;
}
@
Override
public
String getConnectionString()
{
return
connectionString;
}
@
Override
public int
getNegotiatedSessionTimeoutMs()
{
return (
zooKeeperHandle != null) ?
zooKeeperHandle.
getSessionTimeout() : 0;
}
};
return
zooKeeperHandle;
}
}
@
Override
public
String getConnectionString()
{
return
connectionString;
}
@
Override
public int
getNegotiatedSessionTimeoutMs()
{
return (
zooKeeperHandle != null) ?
zooKeeperHandle.
getSessionTimeout() : 0;
}
};
}
private void
internalClose() throws
Exception
{
try
{
ZooKeeper zooKeeper = (
helper != null) ?
helper.
getZooKeeper() : null;
if (
zooKeeper != null )
{
Watcher dummyWatcher = new
Watcher()
{
@
Override
public void
process(
WatchedEvent event)
{
}
};
zooKeeper.
register(
dummyWatcher); // clear the default watcher so that no new events get processed by mistake
zooKeeper.
close();
}
}
catch (
InterruptedException dummy )
{
Thread.
currentThread().
interrupt();
}
}
}