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/**
* 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.framework.recipes.cache;
/**
* POJO that abstracts a change to a path
*/
public class TreeCacheEvent
{
private final Type type;
private final ChildData data;
/**
* Type of change
*/
public enum Type
{
/**
* A node was added.
*/
NODE_ADDED,
/**
* A node's data was changed
*/
NODE_UPDATED,
/**
* A node was removed from the tree
*/
NODE_REMOVED,
/**
* Called when the connection has changed to {@link org.apache.curator.framework.state.ConnectionState#SUSPENDED}
*
* This is exposed so that users of the class can be notified of issues that *might* affect normal operation.
* The TreeCache is written such that listeners are not expected to do anything special on this
* event, except for those people who want to cause some application-specific logic to fire when this occurs.
* While the connection is down, the TreeCache will continue to have its state from before it lost
* the connection and after the connection is restored, the TreeCache will emit normal child events
* for all of the adds, deletes and updates that happened during the time that it was disconnected.
*
*/
CONNECTION_SUSPENDED,
/**
* Called when the connection has changed to {@link org.apache.curator.framework.state.ConnectionState#RECONNECTED}
*
* This is exposed so that users of the class can be notified of issues that *might* affect normal operation.
* The TreeCache is written such that listeners are not expected to do anything special on this
* event, except for those people who want to cause some application-specific logic to fire when this occurs.
* While the connection is down, the TreeCache will continue to have its state from before it lost
* the connection and after the connection is restored, the TreeCache will emit normal child events
* for all of the adds, deletes and updates that happened during the time that it was disconnected.
*
*/
CONNECTION_RECONNECTED,
/**
* Called when the connection has changed to {@link org.apache.curator.framework.state.ConnectionState#LOST}
*
* This is exposed so that users of the class can be notified of issues that *might* affect normal operation.
* The TreeCache is written such that listeners are not expected to do anything special on this
* event, except for those people who want to cause some application-specific logic to fire when this occurs.
* While the connection is down, the TreeCache will continue to have its state from before it lost
* the connection and after the connection is restored, the TreeCache will emit normal child events
* for all of the adds, deletes and updates that happened during the time that it was disconnected.
*
*/
CONNECTION_LOST,
/**
* Posted after the initial cache has been fully populated.
*
* On startup, the cache synchronizes its internal
* state with the server, publishing a series of {@link #NODE_ADDED} events as new nodes are discovered. Once
* the cachehas been fully synchronized, this {@link #INITIALIZED} this event is published. All events
* published after this event represent actual server-side mutations.
*
* Note: because the initial population is inherently asynchronous, so it's possible to observe server-side changes
* (such as a {@link #NODE_UPDATED}) prior to this event being published.
*
*/
INITIALIZED
}
/**
* @param type event type
* @param data event data or null
*/
public TreeCacheEvent(Type type, ChildData data)
{
this.type = type;
this.data = data;
}
/**
* @return change type
*/
public Type getType()
{
return type;
}
/**
* @return the node's data
*/
public ChildData getData()
{
return data;
}
@Override
public String toString()
{
return TreeCacheEvent.class.getSimpleName() + "{" +
"type=" + type +
", data=" + data +
'}';
}
}