001/* 002 * Licensed to the Apache Software Foundation (ASF) under one 003 * or more contributor license agreements. See the NOTICE file 004 * distributed with this work for additional information 005 * regarding copyright ownership. The ASF licenses this file 006 * to you under the Apache License, Version 2.0 (the 007 * "License"); you may not use this file except in compliance 008 * with the License. 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, 013 * software distributed under the License is distributed on an 014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 015 * KIND, either express or implied. See the License for the 016 * specific language governing permissions and limitations 017 * under the License. 018 * 019 */ 020package org.apache.directory.ldap.client.api.future; 021 022import java.util.concurrent.TimeUnit; 023 024import org.apache.directory.api.ldap.model.message.Response; 025import org.apache.directory.ldap.client.api.LdapConnection; 026 027/** 028 * A Future implementation used in LdapConnection operations for operations 029 * that only get one single response. 030 * 031 * @param <R> The result type returned by this Future's <tt>get</tt> method 032 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a> 033 */ 034public abstract class UniqueResponseFuture<R extends Response> implements ResponseFuture<R> 035{ 036 /** The response */ 037 private R response; 038 039 /** flag to determine if this future is cancelled */ 040 protected boolean cancelled = false; 041 042 /** If the request has been cancelled because of an exception it will be stored here */ 043 protected Throwable cause; 044 045 /** The messageID for this future */ 046 protected int messageId; 047 048 /** The connection used by the request */ 049 protected LdapConnection connection; 050 051 /** A flag set to TRUE when the response has been received */ 052 private volatile boolean done = false; 053 054 /** 055 * Creates a new instance of UniqueResponseFuture. 056 * 057 * @param connection The LdapConnection used by the request 058 * @param messageId The associated message ID 059 */ 060 public UniqueResponseFuture( LdapConnection connection, int messageId ) 061 { 062 this.messageId = messageId; 063 this.connection = connection; 064 } 065 066 067 /** 068 * {@inheritDoc} 069 * @throws InterruptedException if the operation has been cancelled by client 070 */ 071 @Override 072 public synchronized R get() throws InterruptedException 073 { 074 while ( !done && !cancelled ) 075 { 076 wait(); 077 } 078 079 return response; 080 } 081 082 083 /** 084 * {@inheritDoc} 085 * @throws InterruptedException if the operation has been cancelled by client 086 */ 087 @Override 088 public synchronized R get( long timeout, TimeUnit unit ) throws InterruptedException 089 { 090 wait( unit.toMillis( timeout ) ); 091 092 return response; 093 } 094 095 096 /** 097 * Set the associated Response in this Future 098 * 099 * @param response The response to add into the Future 100 * @throws InterruptedException if the operation has been cancelled by client 101 */ 102 public synchronized void set( R response ) throws InterruptedException 103 { 104 this.response = response; 105 106 done = response != null; 107 108 notifyAll(); 109 } 110 111 112 /** 113 * {@inheritDoc} 114 */ 115 @Override 116 public boolean cancel( boolean mayInterruptIfRunning ) 117 { 118 if ( cancelled ) 119 { 120 return cancelled; 121 } 122 123 // set the cancel flag first 124 cancelled = true; 125 126 // Send an abandonRequest only if this future exists 127 if ( !connection.isRequestCompleted( messageId ) ) 128 { 129 connection.abandon( messageId ); 130 } 131 132 // Notify the future 133 try 134 { 135 set( null ); 136 } 137 catch ( InterruptedException ie ) 138 { 139 // Nothing we can do 140 } 141 142 return cancelled; 143 } 144 145 146 /** 147 * {@inheritDoc} 148 */ 149 @Override 150 public boolean isCancelled() 151 { 152 return cancelled; 153 } 154 155 156 /** 157 * This operation is not supported in this implementation of Future. 158 * 159 * {@inheritDoc} 160 */ 161 @Override 162 public boolean isDone() 163 { 164 return done; 165 } 166 167 168 /** 169 * @return the cause 170 */ 171 public Throwable getCause() 172 { 173 return cause; 174 } 175 176 177 /** 178 * Associate a cause to the ResponseFuture 179 * @param cause the cause to set 180 */ 181 public void setCause( Throwable cause ) 182 { 183 this.cause = cause; 184 } 185 186 187 /** 188 * Cancel the Future 189 * 190 */ 191 public void cancel() 192 { 193 // set the cancel flag first 194 cancelled = true; 195 196 // Notify the future 197 try 198 { 199 set( null ); 200 } 201 catch ( InterruptedException ie ) 202 { 203 // Nothing we can do 204 } 205 } 206 207 208 /** 209 * {@inheritDoc} 210 */ 211 @Override 212 public String toString() 213 { 214 StringBuilder sb = new StringBuilder(); 215 216 sb.append( "[msgId : " ).append( messageId ).append( ", " ); 217 sb.append( "Canceled :" ).append( cancelled ).append( "]" ); 218 219 return sb.toString(); 220 } 221}