/**
* 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_voltpatches;
import org.apache.zookeeper_voltpatches.WatchedEvent;
import org.apache.zookeeper_voltpatches.Watcher.Event.KeeperState;
/**
* This interface specifies the public interface an event handler class must
* implement. A ZooKeeper client will get various events from the ZooKeepr
* server it connects to. An application using such a client handles these
* events by registering a callback object with the client. The callback object
* is expected to be an instance of a class that implements Watcher interface.
*
*/
public interface Watcher {
/**
* This interface defines the possible states an Event may represent
*/
public interface Event {
/**
* Enumeration of states the ZooKeeper may be at the event
*/
public enum KeeperState {
/** Unused, this state is never generated by the server */
@Deprecated
Unknown(-1),
/**
* The client is in the disconnected state - it is not connected to
* any server in the ensemble.
*/
Disconnected(0),
/** Unused, this state is never generated by the server */
@Deprecated
NoSyncConnected(1),
/**
* The client is in the connected state - it is connected to a
* server in the ensemble (one of the servers specified in the host
* connection parameter during ZooKeeper client creation).
*/
SyncConnected(3),
/**
* Auth failed state
*
*/
AuthFailed(4),
/**
* The serving cluster has expired this session. The ZooKeeper
* client connection (the session) is no longer valid. You must
* create a new client connection (instantiate a new ZooKeeper
* instance) if you with to access the ensemble.
*/
Expired(-112);
private final int intValue; // Integer representation of value
// for sending over wire
KeeperState(int intValue) {
this.intValue = intValue;
}
public int getIntValue() {
return intValue;
}
public static KeeperState fromInt(int intValue) {
switch (intValue) {
case -1:
return KeeperState.Unknown;
case 0:
return KeeperState.Disconnected;
case 1:
return KeeperState.NoSyncConnected;
case 3:
return KeeperState.SyncConnected;
case 4:
return KeeperState.AuthFailed;
case -112:
return KeeperState.Expired;
default:
throw new RuntimeException(
"Invalid integer value for conversion to KeeperState");
}
}
}
/**
* Enumeration of types of events that may occur on the ZooKeeper
*/
public enum EventType {
None(-1), NodeCreated(1), NodeDeleted(2), NodeDataChanged(3), NodeChildrenChanged(
4);
private final int intValue; // Integer representation of value
// for sending over wire
EventType(int intValue) {
this.intValue = intValue;
}
public int getIntValue() {
return intValue;
}
public static EventType fromInt(int intValue) {
switch (intValue) {
case -1:
return EventType.None;
case 1:
return EventType.NodeCreated;
case 2:
return EventType.NodeDeleted;
case 3:
return EventType.NodeDataChanged;
case 4:
return EventType.NodeChildrenChanged;
default:
throw new RuntimeException(
"Invalid integer value for conversion to EventType");
}
}
}
}
abstract public void process(WatchedEvent event);
}