001/*
002 * JPPF.
003 * Copyright (C) 2005-2018 JPPF Team.
004 * http://www.jppf.org
005 *
006 * Licensed under the Apache License, Version 2.0 (the "License");
007 * you may not use this file except in compliance with the License.
008 * You may obtain a copy of the License at
009 *
010 *   http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018
019package org.jppf.load.balancer.persistence;
020
021import java.util.concurrent.locks.Lock;
022
023/**
024 * This interface is implemented by load-balancers that wish to persist their state.
025 * @author Laurent Cohen
026 * @since 6.0
027 */
028public interface PersistentState {
029  /**
030   * Get this bundler's state.
031   * @return an Object representing the state of the load-balancer.
032   */
033  Object getState();
034
035  /**
036   * Set this bundler's state.
037   * @param state an Object representing the state of the load-balancer.
038   */
039  void setState(Object state);
040
041  /**
042   * Get a lock that can be used to synchronize access to the load-balancer state.
043   * The main usage is to avoid race conditions when the state is serialized by the persistence thread,
044   * while it is being updated, in particular via its {@code feedback()} method, in another thread.
045   * @return a {@link Lock} object.
046   */
047  Lock getStateLock();
048}