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 * https://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 // no need to wait if already done or cancelled 091 if ( !done && !cancelled ) 092 { 093 wait( unit.toMillis( timeout ) ); 094 } 095 096 return response; 097 } 098 099 100 /** 101 * Set the associated Response in this Future 102 * 103 * @param response The response to add into the Future 104 * @throws InterruptedException if the operation has been cancelled by client 105 */ 106 public synchronized void set( R response ) throws InterruptedException 107 { 108 this.response = response; 109 110 done = response != null; 111 112 notifyAll(); 113 } 114 115 116 /** 117 * {@inheritDoc} 118 */ 119 @Override 120 public boolean cancel( boolean mayInterruptIfRunning ) 121 { 122 if ( cancelled ) 123 { 124 return cancelled; 125 } 126 127 // set the cancel flag first 128 cancelled = true; 129 130 // Send an abandonRequest only if this future exists 131 if ( !connection.isRequestCompleted( messageId ) ) 132 { 133 connection.abandon( messageId ); 134 } 135 136 // Notify the future 137 try 138 { 139 set( null ); 140 } 141 catch ( InterruptedException ie ) 142 { 143 // Nothing we can do 144 } 145 146 return cancelled; 147 } 148 149 150 /** 151 * {@inheritDoc} 152 */ 153 @Override 154 public boolean isCancelled() 155 { 156 return cancelled; 157 } 158 159 160 /** 161 * This operation is not supported in this implementation of Future. 162 * 163 * {@inheritDoc} 164 */ 165 @Override 166 public boolean isDone() 167 { 168 return done; 169 } 170 171 172 /** 173 * @return the cause 174 */ 175 public Throwable getCause() 176 { 177 return cause; 178 } 179 180 181 /** 182 * Associate a cause to the ResponseFuture 183 * @param cause the cause to set 184 */ 185 public void setCause( Throwable cause ) 186 { 187 this.cause = cause; 188 } 189 190 191 /** 192 * Cancel the Future 193 * 194 */ 195 public void cancel() 196 { 197 // set the cancel flag first 198 cancelled = true; 199 200 // Notify the future 201 try 202 { 203 set( null ); 204 } 205 catch ( InterruptedException ie ) 206 { 207 // Nothing we can do 208 } 209 } 210 211 212 /** 213 * {@inheritDoc} 214 */ 215 @Override 216 public String toString() 217 { 218 StringBuilder sb = new StringBuilder(); 219 220 sb.append( "[msgId : " ).append( messageId ).append( ", " ); 221 sb.append( "Canceled :" ).append( cancelled ).append( "]" ); 222 223 return sb.toString(); 224 } 225}