IEndPointStateChangeSubscriber.java

/**
 * 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 com.facebook.infrastructure.gms;

import com.facebook.infrastructure.net.EndPoint;

/**
 * This is called by an instance of the IEndPointStateChangePublisher to notify
 * interested parties about changes in the the state associated with any endpoint.
 * For instance if node A figures there is a changes in state for an endpoint B
 * it notifies all interested parties of this change. It is upto to the registered
 * instance to decide what he does with this change. Not all modules maybe interested 
 * in all state changes.
 *  
 * Author : Avinash Lakshman ( alakshman@facebook.com) & Prashant Malik ( pmalik@facebook.com )
 */

public interface IEndPointStateChangeSubscriber
{
    /**
     * Use to inform interested parties about the change in the state
     * for specified endpoint
     * 
     * @param endpoint endpoint for which the state change occured.
     * @param epState state that actually changed for the above endpoint.
     */
    public void onChange(EndPoint endpoint, EndPointState epState);
}