ConfigurationChangeListener.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 org.apache.falcon.service;

import org.apache.falcon.FalconException;
import org.apache.falcon.entity.v0.Entity;

/**
 * Configuration change notification listener.
 */
public interface ConfigurationChangeListener {

    /**
     * This is upon adding a new entity to Store.
     *
     * @param entity entity object
     * @throws FalconException
     */
    void onAdd(Entity entity) throws FalconException;

    /**
     * This is upon removing an existing entity from the Store.
     *
     * @param entity entity object
     * @throws FalconException
     */
    void onRemove(Entity entity) throws FalconException;

    /**
     * This is upon updating an entity to the store.
     *
     * @param oldEntity old entity object
     * @param newEntity updated entity object
     * @throws FalconException
     */
    void onChange(Entity oldEntity, Entity newEntity) throws FalconException;

    /**
     * This is when existing entities are read from the store during startup.
     *
     * @param entity entity object
     * @throws FalconException
     */
    void onReload(Entity entity) throws FalconException;
}