001/* 002 * The contents of this file are subject to the terms of the Common Development and 003 * Distribution License (the License). You may not use this file except in compliance with the 004 * License. 005 * 006 * You can obtain a copy of the License at legal/CDDLv1.0.txt. See the License for the 007 * specific language governing permission and limitations under the License. 008 * 009 * When distributing Covered Software, include this CDDL Header Notice in each file and include 010 * the License file at legal/CDDLv1.0.txt. If applicable, add the following below the CDDL 011 * Header, with the fields enclosed by brackets [] replaced by your own identifying 012 * information: "Portions Copyright [year] [name of copyright owner]". 013 * 014 * Copyright 2013-2016 ForgeRock AS. 015 */ 016 017package org.forgerock.opendj.ldap; 018 019import static com.forgerock.opendj.ldap.CoreMessages.LOAD_BALANCER_EVENT_LISTENER_LOG_OFFLINE; 020import static com.forgerock.opendj.ldap.CoreMessages.LOAD_BALANCER_EVENT_LISTENER_LOG_ONLINE; 021 022import java.util.EventListener; 023 024import org.forgerock.i18n.slf4j.LocalizedLogger; 025 026/** 027 * An object that registers to be notified when a connection factory associated 028 * with a load-balancer changes state from offline to online or vice-versa. 029 * <p> 030 * <b>NOTE:</b> load-balancer implementations must ensure that only one event is 031 * sent at a time. Event listener implementations should not need to be thread 032 * safe. 033 * 034 * @see Connections#LOAD_BALANCER_EVENT_LISTENER 035 */ 036public interface LoadBalancerEventListener extends EventListener { 037 /** 038 * An event listener implementation which logs events to the LoadBalancingAlgorithm logger. This event listener is 039 * the default implementation configured using the {@link Connections#LOAD_BALANCER_EVENT_LISTENER} 040 * option. 041 */ 042 LoadBalancerEventListener LOG_EVENTS = new LoadBalancerEventListener() { 043 private final LocalizedLogger logger = LocalizedLogger.getLocalizedLogger(LoadBalancer.class); 044 045 @Override 046 public void handleConnectionFactoryOnline(final ConnectionFactory factory) { 047 logger.info(LOAD_BALANCER_EVENT_LISTENER_LOG_ONLINE.get(factory)); 048 } 049 050 @Override 051 public void handleConnectionFactoryOffline(final ConnectionFactory factory, final LdapException error) { 052 logger.warn(LOAD_BALANCER_EVENT_LISTENER_LOG_OFFLINE.get(factory, error.getMessage())); 053 } 054 }; 055 056 /** An event listener implementation which ignores all events. */ 057 LoadBalancerEventListener NO_OP = new LoadBalancerEventListener() { 058 @Override 059 public void handleConnectionFactoryOnline(final ConnectionFactory factory) { 060 // Do nothing. 061 } 062 063 @Override 064 public void handleConnectionFactoryOffline(final ConnectionFactory factory, final LdapException error) { 065 // Do nothing. 066 } 067 }; 068 069 /** 070 * Invoked when the load-balancer is unable to obtain a connection from the 071 * specified connection factory. The connection factory will be removed from 072 * the load-balancer and monitored periodically in order to determine when 073 * it is available again, at which point an online notification event will 074 * occur. 075 * 076 * @param factory 077 * The connection factory which has failed. 078 * @param error 079 * The last error that occurred. 080 */ 081 void handleConnectionFactoryOffline(ConnectionFactory factory, LdapException error); 082 083 /** 084 * Invoked when the load-balancer detects that a previously offline 085 * connection factory is available for use again. 086 * 087 * @param factory 088 * The connection factory which is now available for use. 089 */ 090 void handleConnectionFactoryOnline(ConnectionFactory factory); 091}