001 /* 002 * CDDL HEADER START 003 * 004 * The contents of this file are subject to the terms of the 005 * Common Development and Distribution License, Version 1.0 only 006 * (the "License"). You may not use this file except in compliance 007 * with the License. 008 * 009 * You can obtain a copy of the license at 010 * trunk/opends/resource/legal-notices/OpenDS.LICENSE 011 * or https://OpenDS.dev.java.net/OpenDS.LICENSE. 012 * See the License for the specific language governing permissions 013 * and limitations under the License. 014 * 015 * When distributing Covered Code, include this CDDL HEADER in each 016 * file and include the License file at 017 * trunk/opends/resource/legal-notices/OpenDS.LICENSE. If applicable, 018 * add the following below this CDDL HEADER, with the fields enclosed 019 * by brackets "[]" replaced with your own identifying information: 020 * Portions Copyright [yyyy] [name of copyright owner] 021 * 022 * CDDL HEADER END 023 * 024 * 025 * Copyright 2006-2008 Sun Microsystems, Inc. 026 */ 027 package org.opends.server.replication.server; 028 029 import java.util.LinkedList; 030 031 import org.opends.server.replication.common.ChangeNumber; 032 033 /** 034 * This class is used to store the list of acks received for 035 * a Given Update Messages. 036 * 037 * The acks are kept only for the update that are marked, hopefully this 038 * should be a limited number of updates and in all cases, LDAP servers 039 * operations are going to be blocked waiting for these acks so they 040 * won't be able to generate a huge number of such messages. 041 * 042 * Therefore, the amount of memory used keeping those changes is not a problem, 043 */ 044 public class AckMessageList 045 { 046 // The ChangeNumber of the updates that was acked 047 // or that is waiting acks 048 private ChangeNumber changeNumber; 049 050 // The list of serverIdentifiers for which acks have been received so far 051 // can be empty when no acks have been received 052 private LinkedList<Short> acks; 053 054 private int numExpectedAcks; 055 056 /** 057 * Creates a new AckMessageList for a given ChangeNumber. 058 * 059 * @param changeNumber The ChangeNumber for which the ack list is created. 060 * @param numExpectedAcks The number of acks waited before acking the 061 * original change. 062 */ 063 public AckMessageList(ChangeNumber changeNumber, int numExpectedAcks) 064 { 065 acks = new LinkedList<Short>(); 066 this.changeNumber = changeNumber; 067 this.numExpectedAcks = numExpectedAcks; 068 } 069 070 /** 071 * Get the ChangeNumber of this Ack Message List. 072 * @return Returns the changeNumber. 073 */ 074 public ChangeNumber getChangeNumber() 075 { 076 return changeNumber; 077 } 078 079 /** 080 * Add an ack from a given LDAP server to the ack list. 081 * 082 * @param serverId the identifier of the LDAP server. 083 */ 084 public synchronized void addAck(short serverId) 085 { 086 acks.add(serverId); 087 } 088 089 /** 090 * This method can be used to check if all acks have been received for the 091 * ChangeNumber managed by this list. 092 * @return A boolean indicating if all acks have been received for the 093 * ChangeNumber managed by this list. 094 */ 095 public boolean completed() 096 { 097 return (acks.size() >= numExpectedAcks); 098 } 099 }