001 /* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017 018 package org.apache.commons.pool.impl; 019 020 import java.util.ArrayList; 021 import java.util.Collection; 022 import java.util.Iterator; 023 import java.util.LinkedList; 024 import java.util.List; 025 import java.util.NoSuchElementException; 026 import java.util.TimerTask; 027 028 import org.apache.commons.pool.BaseObjectPool; 029 import org.apache.commons.pool.ObjectPool; 030 import org.apache.commons.pool.PoolUtils; 031 import org.apache.commons.pool.PoolableObjectFactory; 032 import org.apache.commons.pool.impl.GenericKeyedObjectPool.ObjectTimestampPair; 033 034 /** 035 * A configurable {@link ObjectPool} implementation. 036 * <p> 037 * When coupled with the appropriate {@link PoolableObjectFactory}, 038 * <tt>GenericObjectPool</tt> provides robust pooling functionality for 039 * arbitrary objects. 040 * <p> 041 * A <tt>GenericObjectPool</tt> provides a number of configurable parameters: 042 * <ul> 043 * <li> 044 * {@link #setMaxActive <i>maxActive</i>} controls the maximum number of 045 * objects that can be allocated by the pool (checked out to clients, or 046 * idle awaiting checkout) at a given time. When non-positive, there is no 047 * limit to the number of objects that can be managed by the pool at one time. 048 * When {@link #setMaxActive <i>maxActive</i>} is reached, the pool is said 049 * to be exhausted. The default setting for this parameter is 8. 050 * </li> 051 * <li> 052 * {@link #setMaxIdle <i>maxIdle</i>} controls the maximum number of objects 053 * that can sit idle in the pool at any time. When negative, there is no 054 * limit to the number of objects that may be idle at one time. The default 055 * setting for this parameter is 8. 056 * </li> 057 * <li> 058 * {@link #setWhenExhaustedAction <i>whenExhaustedAction</i>} specifies the 059 * behavior of the {@link #borrowObject} method when the pool is exhausted: 060 * <ul> 061 * <li> 062 * When {@link #setWhenExhaustedAction <i>whenExhaustedAction</i>} is 063 * {@link #WHEN_EXHAUSTED_FAIL}, {@link #borrowObject} will throw 064 * a {@link NoSuchElementException} 065 * </li> 066 * <li> 067 * When {@link #setWhenExhaustedAction <i>whenExhaustedAction</i>} is 068 * {@link #WHEN_EXHAUSTED_GROW}, {@link #borrowObject} will create a new 069 * object and return it (essentially making {@link #setMaxActive <i>maxActive</i>} 070 * meaningless.) 071 * </li> 072 * <li> 073 * When {@link #setWhenExhaustedAction <i>whenExhaustedAction</i>} 074 * is {@link #WHEN_EXHAUSTED_BLOCK}, {@link #borrowObject} will block 075 * (invoke {@link Object#wait()}) until a new or idle object is available. 076 * If a positive {@link #setMaxWait <i>maxWait</i>} 077 * value is supplied, then {@link #borrowObject} will block for at 078 * most that many milliseconds, after which a {@link NoSuchElementException} 079 * will be thrown. If {@link #setMaxWait <i>maxWait</i>} is non-positive, 080 * the {@link #borrowObject} method will block indefinitely. 081 * </li> 082 * </ul> 083 * The default <code>whenExhaustedAction</code> setting is 084 * {@link #WHEN_EXHAUSTED_BLOCK} and the default <code>maxWait</code> 085 * setting is -1. By default, therefore, <code>borrowObject</code> will 086 * block indefinitely until an idle instance becomes available. 087 * </li> 088 * <li> 089 * When {@link #setTestOnBorrow <i>testOnBorrow</i>} is set, the pool will 090 * attempt to validate each object before it is returned from the 091 * {@link #borrowObject} method. (Using the provided factory's 092 * {@link PoolableObjectFactory#validateObject} method.) Objects that fail 093 * to validate will be dropped from the pool, and a different object will 094 * be borrowed. The default setting for this parameter is 095 * <code>false.</code> 096 * </li> 097 * <li> 098 * When {@link #setTestOnReturn <i>testOnReturn</i>} is set, the pool will 099 * attempt to validate each object before it is returned to the pool in the 100 * {@link #returnObject} method. (Using the provided factory's 101 * {@link PoolableObjectFactory#validateObject} 102 * method.) Objects that fail to validate will be dropped from the pool. 103 * The default setting for this parameter is <code>false.</code> 104 * </li> 105 * </ul> 106 * <p> 107 * Optionally, one may configure the pool to examine and possibly evict objects 108 * as they sit idle in the pool and to ensure that a minimum number of idle 109 * objects are available. This is performed by an "idle object eviction" 110 * thread, which runs asynchronously. Caution should be used when configuring 111 * this optional feature. Eviction runs contend with client threads for access 112 * to objects in the pool, so if they run too frequently performance issues may 113 * result. The idle object eviction thread may be configured using the following 114 * attributes: 115 * <ul> 116 * <li> 117 * {@link #setTimeBetweenEvictionRunsMillis <i>timeBetweenEvictionRunsMillis</i>} 118 * indicates how long the eviction thread should sleep before "runs" of examining 119 * idle objects. When non-positive, no eviction thread will be launched. The 120 * default setting for this parameter is -1 (i.e., idle object eviction is 121 * disabled by default). 122 * </li> 123 * <li> 124 * {@link #setMinEvictableIdleTimeMillis <i>minEvictableIdleTimeMillis</i>} 125 * specifies the minimum amount of time that an object may sit idle in the pool 126 * before it is eligible for eviction due to idle time. When non-positive, no object 127 * will be dropped from the pool due to idle time alone. This setting has no 128 * effect unless <code>timeBetweenEvictionRunsMillis > 0.</code> The default 129 * setting for this parameter is 30 minutes. 130 * </li> 131 * <li> 132 * {@link #setTestWhileIdle <i>testWhileIdle</i>} indicates whether or not idle 133 * objects should be validated using the factory's 134 * {@link PoolableObjectFactory#validateObject} method. Objects that fail to 135 * validate will be dropped from the pool. This setting has no effect unless 136 * <code>timeBetweenEvictionRunsMillis > 0.</code> The default setting for 137 * this parameter is <code>false.</code> 138 * </li> 139 * <li> 140 * {@link #setSoftMinEvictableIdleTimeMillis <i>softMinEvictableIdleTimeMillis</i>} 141 * specifies the minimum amount of time an object may sit idle in the pool 142 * before it is eligible for eviction by the idle object evictor 143 * (if any), with the extra condition that at least "minIdle" object instances 144 * remain in the pool. When non-positive, no objects will be evicted from the pool 145 * due to idle time alone. This setting has no effect unless 146 * <code>timeBetweenEvictionRunsMillis > 0.</code> and it is superceded by 147 * {@link #setMinEvictableIdleTimeMillis <i>minEvictableIdleTimeMillis</i>} 148 * (that is, if <code>minEvictableIdleTimeMillis</code> is positive, then 149 * <code>softMinEvictableIdleTimeMillis</code> is ignored). The default setting for 150 * this parameter is -1 (disabled). 151 * </li> 152 * <li> 153 * {@link #setNumTestsPerEvictionRun <i>numTestsPerEvictionRun</i>} 154 * determines the number of objects examined in each run of the idle object 155 * evictor. This setting has no effect unless 156 * <code>timeBetweenEvictionRunsMillis > 0.</code> The default setting for 157 * this parameter is 3. 158 * </li> 159 * </ul> 160 * <p> 161 * <p> 162 * The pool can be configured to behave as a LIFO queue with respect to idle 163 * objects - always returning the most recently used object from the pool, 164 * or as a FIFO queue, where borrowObject always returns the oldest object 165 * in the idle object pool. 166 * <ul> 167 * <li> 168 * {@link #setLifo <i>lifo</i>} 169 * determines whether or not the pool returns idle objects in 170 * last-in-first-out order. The default setting for this parameter is 171 * <code>true.</code> 172 * </li> 173 * </ul> 174 * <p> 175 * GenericObjectPool is not usable without a {@link PoolableObjectFactory}. A 176 * non-<code>null</code> factory must be provided either as a constructor argument 177 * or via a call to {@link #setFactory} before the pool is used. 178 * <p> 179 * Implementation note: To prevent possible deadlocks, care has been taken to 180 * ensure that no call to a factory method will occur within a synchronization 181 * block. See POOL-125 and DBCP-44 for more information. 182 * 183 * @see GenericKeyedObjectPool 184 * @author Rodney Waldhoff 185 * @author Dirk Verbeeck 186 * @author Sandy McArthur 187 * @version $Revision: 1086190 $ $Date: 2011-03-28 04:22:08 -0700 (Mon, 28 Mar 2011) $ 188 * @since Pool 1.0 189 */ 190 public class GenericObjectPool extends BaseObjectPool implements ObjectPool { 191 192 //--- public constants ------------------------------------------- 193 194 /** 195 * A "when exhausted action" type indicating that when the pool is 196 * exhausted (i.e., the maximum number of active objects has 197 * been reached), the {@link #borrowObject} 198 * method should fail, throwing a {@link NoSuchElementException}. 199 * @see #WHEN_EXHAUSTED_BLOCK 200 * @see #WHEN_EXHAUSTED_GROW 201 * @see #setWhenExhaustedAction 202 */ 203 public static final byte WHEN_EXHAUSTED_FAIL = 0; 204 205 /** 206 * A "when exhausted action" type indicating that when the pool 207 * is exhausted (i.e., the maximum number 208 * of active objects has been reached), the {@link #borrowObject} 209 * method should block until a new object is available, or the 210 * {@link #getMaxWait maximum wait time} has been reached. 211 * @see #WHEN_EXHAUSTED_FAIL 212 * @see #WHEN_EXHAUSTED_GROW 213 * @see #setMaxWait 214 * @see #getMaxWait 215 * @see #setWhenExhaustedAction 216 */ 217 public static final byte WHEN_EXHAUSTED_BLOCK = 1; 218 219 /** 220 * A "when exhausted action" type indicating that when the pool is 221 * exhausted (i.e., the maximum number 222 * of active objects has been reached), the {@link #borrowObject} 223 * method should simply create a new object anyway. 224 * @see #WHEN_EXHAUSTED_FAIL 225 * @see #WHEN_EXHAUSTED_GROW 226 * @see #setWhenExhaustedAction 227 */ 228 public static final byte WHEN_EXHAUSTED_GROW = 2; 229 230 /** 231 * The default cap on the number of "sleeping" instances in the pool. 232 * @see #getMaxIdle 233 * @see #setMaxIdle 234 */ 235 public static final int DEFAULT_MAX_IDLE = 8; 236 237 /** 238 * The default minimum number of "sleeping" instances in the pool 239 * before before the evictor thread (if active) spawns new objects. 240 * @see #getMinIdle 241 * @see #setMinIdle 242 */ 243 public static final int DEFAULT_MIN_IDLE = 0; 244 245 /** 246 * The default cap on the total number of active instances from the pool. 247 * @see #getMaxActive 248 */ 249 public static final int DEFAULT_MAX_ACTIVE = 8; 250 251 /** 252 * The default "when exhausted action" for the pool. 253 * @see #WHEN_EXHAUSTED_BLOCK 254 * @see #WHEN_EXHAUSTED_FAIL 255 * @see #WHEN_EXHAUSTED_GROW 256 * @see #setWhenExhaustedAction 257 */ 258 public static final byte DEFAULT_WHEN_EXHAUSTED_ACTION = WHEN_EXHAUSTED_BLOCK; 259 260 /** 261 * The default LIFO status. True means that borrowObject returns the 262 * most recently used ("last in") idle object in the pool (if there are 263 * idle instances available). False means that the pool behaves as a FIFO 264 * queue - objects are taken from the idle object pool in the order that 265 * they are returned to the pool. 266 * @see #setLifo 267 * @since 1.4 268 */ 269 public static final boolean DEFAULT_LIFO = true; 270 271 /** 272 * The default maximum amount of time (in milliseconds) the 273 * {@link #borrowObject} method should block before throwing 274 * an exception when the pool is exhausted and the 275 * {@link #getWhenExhaustedAction "when exhausted" action} is 276 * {@link #WHEN_EXHAUSTED_BLOCK}. 277 * @see #getMaxWait 278 * @see #setMaxWait 279 */ 280 public static final long DEFAULT_MAX_WAIT = -1L; 281 282 /** 283 * The default "test on borrow" value. 284 * @see #getTestOnBorrow 285 * @see #setTestOnBorrow 286 */ 287 public static final boolean DEFAULT_TEST_ON_BORROW = false; 288 289 /** 290 * The default "test on return" value. 291 * @see #getTestOnReturn 292 * @see #setTestOnReturn 293 */ 294 public static final boolean DEFAULT_TEST_ON_RETURN = false; 295 296 /** 297 * The default "test while idle" value. 298 * @see #getTestWhileIdle 299 * @see #setTestWhileIdle 300 * @see #getTimeBetweenEvictionRunsMillis 301 * @see #setTimeBetweenEvictionRunsMillis 302 */ 303 public static final boolean DEFAULT_TEST_WHILE_IDLE = false; 304 305 /** 306 * The default "time between eviction runs" value. 307 * @see #getTimeBetweenEvictionRunsMillis 308 * @see #setTimeBetweenEvictionRunsMillis 309 */ 310 public static final long DEFAULT_TIME_BETWEEN_EVICTION_RUNS_MILLIS = -1L; 311 312 /** 313 * The default number of objects to examine per run in the 314 * idle object evictor. 315 * @see #getNumTestsPerEvictionRun 316 * @see #setNumTestsPerEvictionRun 317 * @see #getTimeBetweenEvictionRunsMillis 318 * @see #setTimeBetweenEvictionRunsMillis 319 */ 320 public static final int DEFAULT_NUM_TESTS_PER_EVICTION_RUN = 3; 321 322 /** 323 * The default value for {@link #getMinEvictableIdleTimeMillis}. 324 * @see #getMinEvictableIdleTimeMillis 325 * @see #setMinEvictableIdleTimeMillis 326 */ 327 public static final long DEFAULT_MIN_EVICTABLE_IDLE_TIME_MILLIS = 1000L * 60L * 30L; 328 329 /** 330 * The default value for {@link #getSoftMinEvictableIdleTimeMillis}. 331 * @see #getSoftMinEvictableIdleTimeMillis 332 * @see #setSoftMinEvictableIdleTimeMillis 333 */ 334 public static final long DEFAULT_SOFT_MIN_EVICTABLE_IDLE_TIME_MILLIS = -1; 335 336 //--- constructors ----------------------------------------------- 337 338 /** 339 * Create a new <tt>GenericObjectPool</tt> with default properties. 340 */ 341 public GenericObjectPool() { 342 this(null, DEFAULT_MAX_ACTIVE, DEFAULT_WHEN_EXHAUSTED_ACTION, DEFAULT_MAX_WAIT, DEFAULT_MAX_IDLE, 343 DEFAULT_MIN_IDLE, DEFAULT_TEST_ON_BORROW, DEFAULT_TEST_ON_RETURN, DEFAULT_TIME_BETWEEN_EVICTION_RUNS_MILLIS, 344 DEFAULT_NUM_TESTS_PER_EVICTION_RUN, DEFAULT_MIN_EVICTABLE_IDLE_TIME_MILLIS, DEFAULT_TEST_WHILE_IDLE); 345 } 346 347 /** 348 * Create a new <tt>GenericObjectPool</tt> using the specified factory. 349 * @param factory the (possibly <tt>null</tt>)PoolableObjectFactory to use to create, validate and destroy objects 350 */ 351 public GenericObjectPool(PoolableObjectFactory factory) { 352 this(factory, DEFAULT_MAX_ACTIVE, DEFAULT_WHEN_EXHAUSTED_ACTION, DEFAULT_MAX_WAIT, DEFAULT_MAX_IDLE, 353 DEFAULT_MIN_IDLE, DEFAULT_TEST_ON_BORROW, DEFAULT_TEST_ON_RETURN, DEFAULT_TIME_BETWEEN_EVICTION_RUNS_MILLIS, 354 DEFAULT_NUM_TESTS_PER_EVICTION_RUN, DEFAULT_MIN_EVICTABLE_IDLE_TIME_MILLIS, DEFAULT_TEST_WHILE_IDLE); 355 } 356 357 /** 358 * Create a new <tt>GenericObjectPool</tt> using the specified values. 359 * @param factory the (possibly <tt>null</tt>)PoolableObjectFactory to use to create, validate and destroy objects 360 * @param config a non-<tt>null</tt> {@link GenericObjectPool.Config} describing my configuration 361 */ 362 public GenericObjectPool(PoolableObjectFactory factory, GenericObjectPool.Config config) { 363 this(factory, config.maxActive, config.whenExhaustedAction, config.maxWait, config.maxIdle, config.minIdle, 364 config.testOnBorrow, config.testOnReturn, config.timeBetweenEvictionRunsMillis, 365 config.numTestsPerEvictionRun, config.minEvictableIdleTimeMillis, config.testWhileIdle, 366 config.softMinEvictableIdleTimeMillis, config.lifo); 367 } 368 369 /** 370 * Create a new <tt>GenericObjectPool</tt> using the specified values. 371 * @param factory the (possibly <tt>null</tt>)PoolableObjectFactory to use to create, validate and destroy objects 372 * @param maxActive the maximum number of objects that can be borrowed from me at one time (see {@link #setMaxActive}) 373 */ 374 public GenericObjectPool(PoolableObjectFactory factory, int maxActive) { 375 this(factory, maxActive, DEFAULT_WHEN_EXHAUSTED_ACTION, DEFAULT_MAX_WAIT, DEFAULT_MAX_IDLE, DEFAULT_MIN_IDLE, 376 DEFAULT_TEST_ON_BORROW, DEFAULT_TEST_ON_RETURN, DEFAULT_TIME_BETWEEN_EVICTION_RUNS_MILLIS, 377 DEFAULT_NUM_TESTS_PER_EVICTION_RUN, DEFAULT_MIN_EVICTABLE_IDLE_TIME_MILLIS, DEFAULT_TEST_WHILE_IDLE); 378 } 379 380 /** 381 * Create a new <tt>GenericObjectPool</tt> using the specified values. 382 * @param factory the (possibly <tt>null</tt>)PoolableObjectFactory to use to create, validate and destroy objects 383 * @param maxActive the maximum number of objects that can be borrowed from me at one time (see {@link #setMaxActive}) 384 * @param whenExhaustedAction the action to take when the pool is exhausted (see {@link #getWhenExhaustedAction}) 385 * @param maxWait the maximum amount of time to wait for an idle object when the pool is exhausted an and 386 * <i>whenExhaustedAction</i> is {@link #WHEN_EXHAUSTED_BLOCK} (otherwise ignored) (see {@link #getMaxWait}) 387 */ 388 public GenericObjectPool(PoolableObjectFactory factory, int maxActive, byte whenExhaustedAction, long maxWait) { 389 this(factory, maxActive, whenExhaustedAction, maxWait, DEFAULT_MAX_IDLE, DEFAULT_MIN_IDLE, DEFAULT_TEST_ON_BORROW, 390 DEFAULT_TEST_ON_RETURN, DEFAULT_TIME_BETWEEN_EVICTION_RUNS_MILLIS, DEFAULT_NUM_TESTS_PER_EVICTION_RUN, 391 DEFAULT_MIN_EVICTABLE_IDLE_TIME_MILLIS, DEFAULT_TEST_WHILE_IDLE); 392 } 393 394 /** 395 * Create a new <tt>GenericObjectPool</tt> using the specified values. 396 * @param factory the (possibly <tt>null</tt>)PoolableObjectFactory to use to create, validate and destroy objects 397 * @param maxActive the maximum number of objects that can be borrowed at one time (see {@link #setMaxActive}) 398 * @param whenExhaustedAction the action to take when the pool is exhausted (see {@link #getWhenExhaustedAction}) 399 * @param maxWait the maximum amount of time to wait for an idle object when the pool is exhausted an and 400 * <i>whenExhaustedAction</i> is {@link #WHEN_EXHAUSTED_BLOCK} (otherwise ignored) (see {@link #getMaxWait}) 401 * @param testOnBorrow whether or not to validate objects before they are returned by the {@link #borrowObject} method 402 * (see {@link #getTestOnBorrow}) 403 * @param testOnReturn whether or not to validate objects after they are returned to the {@link #returnObject} method 404 * (see {@link #getTestOnReturn}) 405 */ 406 public GenericObjectPool(PoolableObjectFactory factory, int maxActive, byte whenExhaustedAction, long maxWait, 407 boolean testOnBorrow, boolean testOnReturn) { 408 this(factory, maxActive, whenExhaustedAction, maxWait, DEFAULT_MAX_IDLE, DEFAULT_MIN_IDLE, testOnBorrow, 409 testOnReturn, DEFAULT_TIME_BETWEEN_EVICTION_RUNS_MILLIS, DEFAULT_NUM_TESTS_PER_EVICTION_RUN, 410 DEFAULT_MIN_EVICTABLE_IDLE_TIME_MILLIS, DEFAULT_TEST_WHILE_IDLE); 411 } 412 413 /** 414 * Create a new <tt>GenericObjectPool</tt> using the specified values. 415 * @param factory the (possibly <tt>null</tt>)PoolableObjectFactory to use to create, validate and destroy objects 416 * @param maxActive the maximum number of objects that can be borrowed at one time (see {@link #setMaxActive}) 417 * @param whenExhaustedAction the action to take when the pool is exhausted (see {@link #getWhenExhaustedAction}) 418 * @param maxWait the maximum amount of time to wait for an idle object when the pool is exhausted and 419 * <i>whenExhaustedAction</i> is {@link #WHEN_EXHAUSTED_BLOCK} (otherwise ignored) (see {@link #getMaxWait}) 420 * @param maxIdle the maximum number of idle objects in my pool (see {@link #getMaxIdle}) 421 */ 422 public GenericObjectPool(PoolableObjectFactory factory, int maxActive, byte whenExhaustedAction, long maxWait, int maxIdle) { 423 this(factory, maxActive, whenExhaustedAction, maxWait, maxIdle, DEFAULT_MIN_IDLE, DEFAULT_TEST_ON_BORROW, 424 DEFAULT_TEST_ON_RETURN, DEFAULT_TIME_BETWEEN_EVICTION_RUNS_MILLIS, DEFAULT_NUM_TESTS_PER_EVICTION_RUN, 425 DEFAULT_MIN_EVICTABLE_IDLE_TIME_MILLIS, DEFAULT_TEST_WHILE_IDLE); 426 } 427 428 /** 429 * Create a new <tt>GenericObjectPool</tt> using the specified values. 430 * @param factory the (possibly <tt>null</tt>)PoolableObjectFactory to use to create, validate and destroy objects 431 * @param maxActive the maximum number of objects that can be borrowed at one time (see {@link #setMaxActive}) 432 * @param whenExhaustedAction the action to take when the pool is exhausted (see {@link #getWhenExhaustedAction}) 433 * @param maxWait the maximum amount of time to wait for an idle object when the pool is exhausted and 434 * <i>whenExhaustedAction</i> is {@link #WHEN_EXHAUSTED_BLOCK} (otherwise ignored) (see {@link #getMaxWait}) 435 * @param maxIdle the maximum number of idle objects in my pool (see {@link #getMaxIdle}) 436 * @param testOnBorrow whether or not to validate objects before they are returned by the {@link #borrowObject} method 437 * (see {@link #getTestOnBorrow}) 438 * @param testOnReturn whether or not to validate objects after they are returned to the {@link #returnObject} method 439 * (see {@link #getTestOnReturn}) 440 */ 441 public GenericObjectPool(PoolableObjectFactory factory, int maxActive, byte whenExhaustedAction, long maxWait, 442 int maxIdle, boolean testOnBorrow, boolean testOnReturn) { 443 this(factory, maxActive, whenExhaustedAction, maxWait, maxIdle, DEFAULT_MIN_IDLE, testOnBorrow, testOnReturn, 444 DEFAULT_TIME_BETWEEN_EVICTION_RUNS_MILLIS, DEFAULT_NUM_TESTS_PER_EVICTION_RUN, 445 DEFAULT_MIN_EVICTABLE_IDLE_TIME_MILLIS, DEFAULT_TEST_WHILE_IDLE); 446 } 447 448 /** 449 * Create a new <tt>GenericObjectPool</tt> using the specified values. 450 * @param factory the (possibly <tt>null</tt>)PoolableObjectFactory to use to create, validate and destroy objects 451 * @param maxActive the maximum number of objects that can be borrowed at one time (see {@link #setMaxActive}) 452 * @param whenExhaustedAction the action to take when the pool is exhausted (see {@link #setWhenExhaustedAction}) 453 * @param maxWait the maximum amount of time to wait for an idle object when the pool is exhausted and 454 * <i>whenExhaustedAction</i> is {@link #WHEN_EXHAUSTED_BLOCK} (otherwise ignored) (see {@link #setMaxWait}) 455 * @param maxIdle the maximum number of idle objects in my pool (see {@link #setMaxIdle}) 456 * @param testOnBorrow whether or not to validate objects before they are returned by the {@link #borrowObject} 457 * method (see {@link #setTestOnBorrow}) 458 * @param testOnReturn whether or not to validate objects after they are returned to the {@link #returnObject} method 459 * (see {@link #setTestOnReturn}) 460 * @param timeBetweenEvictionRunsMillis the amount of time (in milliseconds) to sleep between examining idle objects 461 * for eviction (see {@link #setTimeBetweenEvictionRunsMillis}) 462 * @param numTestsPerEvictionRun the number of idle objects to examine per run within the idle object eviction thread 463 * (if any) (see {@link #setNumTestsPerEvictionRun}) 464 * @param minEvictableIdleTimeMillis the minimum number of milliseconds an object can sit idle in the pool before it 465 * is eligible for eviction (see {@link #setMinEvictableIdleTimeMillis}) 466 * @param testWhileIdle whether or not to validate objects in the idle object eviction thread, if any 467 * (see {@link #setTestWhileIdle}) 468 */ 469 public GenericObjectPool(PoolableObjectFactory factory, int maxActive, byte whenExhaustedAction, long maxWait, 470 int maxIdle, boolean testOnBorrow, boolean testOnReturn, long timeBetweenEvictionRunsMillis, 471 int numTestsPerEvictionRun, long minEvictableIdleTimeMillis, boolean testWhileIdle) { 472 this(factory, maxActive, whenExhaustedAction, maxWait, maxIdle, DEFAULT_MIN_IDLE, testOnBorrow, testOnReturn, 473 timeBetweenEvictionRunsMillis, numTestsPerEvictionRun, minEvictableIdleTimeMillis, testWhileIdle); 474 } 475 476 /** 477 * Create a new <tt>GenericObjectPool</tt> using the specified values. 478 * @param factory the (possibly <tt>null</tt>)PoolableObjectFactory to use to create, validate and destroy objects 479 * @param maxActive the maximum number of objects that can be borrowed at one time (see {@link #setMaxActive}) 480 * @param whenExhaustedAction the action to take when the pool is exhausted (see {@link #setWhenExhaustedAction}) 481 * @param maxWait the maximum amount of time to wait for an idle object when the pool is exhausted and 482 * <i>whenExhaustedAction</i> is {@link #WHEN_EXHAUSTED_BLOCK} (otherwise ignored) (see {@link #setMaxWait}) 483 * @param maxIdle the maximum number of idle objects in my pool (see {@link #setMaxIdle}) 484 * @param minIdle the minimum number of idle objects in my pool (see {@link #setMinIdle}) 485 * @param testOnBorrow whether or not to validate objects before they are returned by the {@link #borrowObject} method 486 * (see {@link #setTestOnBorrow}) 487 * @param testOnReturn whether or not to validate objects after they are returned to the {@link #returnObject} method 488 * (see {@link #setTestOnReturn}) 489 * @param timeBetweenEvictionRunsMillis the amount of time (in milliseconds) to sleep between examining idle objects 490 * for eviction (see {@link #setTimeBetweenEvictionRunsMillis}) 491 * @param numTestsPerEvictionRun the number of idle objects to examine per run within the idle object eviction thread 492 * (if any) (see {@link #setNumTestsPerEvictionRun}) 493 * @param minEvictableIdleTimeMillis the minimum number of milliseconds an object can sit idle in the pool before 494 * it is eligible for eviction (see {@link #setMinEvictableIdleTimeMillis}) 495 * @param testWhileIdle whether or not to validate objects in the idle object eviction thread, if any 496 * (see {@link #setTestWhileIdle}) 497 */ 498 public GenericObjectPool(PoolableObjectFactory factory, int maxActive, byte whenExhaustedAction, long maxWait, 499 int maxIdle, int minIdle, boolean testOnBorrow, boolean testOnReturn, long timeBetweenEvictionRunsMillis, 500 int numTestsPerEvictionRun, long minEvictableIdleTimeMillis, boolean testWhileIdle) { 501 this(factory, maxActive, whenExhaustedAction, maxWait, maxIdle, minIdle, testOnBorrow, testOnReturn, 502 timeBetweenEvictionRunsMillis, numTestsPerEvictionRun, minEvictableIdleTimeMillis, testWhileIdle, 503 DEFAULT_SOFT_MIN_EVICTABLE_IDLE_TIME_MILLIS); 504 } 505 506 /** 507 * Create a new <tt>GenericObjectPool</tt> using the specified values. 508 * @param factory the (possibly <tt>null</tt>)PoolableObjectFactory to use to create, validate and destroy objects 509 * @param maxActive the maximum number of objects that can be borrowed at one time (see {@link #setMaxActive}) 510 * @param whenExhaustedAction the action to take when the pool is exhausted (see {@link #setWhenExhaustedAction}) 511 * @param maxWait the maximum amount of time to wait for an idle object when the pool is exhausted and 512 * <i>whenExhaustedAction</i> is {@link #WHEN_EXHAUSTED_BLOCK} (otherwise ignored) (see {@link #setMaxWait}) 513 * @param maxIdle the maximum number of idle objects in my pool (see {@link #setMaxIdle}) 514 * @param minIdle the minimum number of idle objects in my pool (see {@link #setMinIdle}) 515 * @param testOnBorrow whether or not to validate objects before they are returned by the {@link #borrowObject} 516 * method (see {@link #setTestOnBorrow}) 517 * @param testOnReturn whether or not to validate objects after they are returned to the {@link #returnObject} 518 * method (see {@link #setTestOnReturn}) 519 * @param timeBetweenEvictionRunsMillis the amount of time (in milliseconds) to sleep between examining idle objects 520 * for eviction (see {@link #setTimeBetweenEvictionRunsMillis}) 521 * @param numTestsPerEvictionRun the number of idle objects to examine per run within the idle object eviction thread 522 * (if any) (see {@link #setNumTestsPerEvictionRun}) 523 * @param minEvictableIdleTimeMillis the minimum number of milliseconds an object can sit idle in the pool before 524 * it is eligible for eviction (see {@link #setMinEvictableIdleTimeMillis}) 525 * @param testWhileIdle whether or not to validate objects in the idle object eviction thread, if any 526 * (see {@link #setTestWhileIdle}) 527 * @param softMinEvictableIdleTimeMillis the minimum number of milliseconds an object can sit idle in the pool before it is 528 * eligible for eviction with the extra condition that at least "minIdle" amount of object remain in the pool. 529 * (see {@link #setSoftMinEvictableIdleTimeMillis}) 530 * @since Pool 1.3 531 */ 532 public GenericObjectPool(PoolableObjectFactory factory, int maxActive, byte whenExhaustedAction, long maxWait, 533 int maxIdle, int minIdle, boolean testOnBorrow, boolean testOnReturn, long timeBetweenEvictionRunsMillis, 534 int numTestsPerEvictionRun, long minEvictableIdleTimeMillis, boolean testWhileIdle, 535 long softMinEvictableIdleTimeMillis) { 536 this(factory, maxActive, whenExhaustedAction, maxWait, maxIdle, minIdle, testOnBorrow, testOnReturn, 537 timeBetweenEvictionRunsMillis, numTestsPerEvictionRun, minEvictableIdleTimeMillis, testWhileIdle, 538 softMinEvictableIdleTimeMillis, DEFAULT_LIFO); 539 } 540 541 /** 542 * Create a new <tt>GenericObjectPool</tt> using the specified values. 543 * @param factory the (possibly <tt>null</tt>)PoolableObjectFactory to use to create, validate and destroy objects 544 * @param maxActive the maximum number of objects that can be borrowed at one time (see {@link #setMaxActive}) 545 * @param whenExhaustedAction the action to take when the pool is exhausted (see {@link #setWhenExhaustedAction}) 546 * @param maxWait the maximum amount of time to wait for an idle object when the pool is exhausted and 547 * <i>whenExhaustedAction</i> is {@link #WHEN_EXHAUSTED_BLOCK} (otherwise ignored) (see {@link #setMaxWait}) 548 * @param maxIdle the maximum number of idle objects in my pool (see {@link #setMaxIdle}) 549 * @param minIdle the minimum number of idle objects in my pool (see {@link #setMinIdle}) 550 * @param testOnBorrow whether or not to validate objects before they are returned by the {@link #borrowObject} 551 * method (see {@link #setTestOnBorrow}) 552 * @param testOnReturn whether or not to validate objects after they are returned to the {@link #returnObject} 553 * method (see {@link #setTestOnReturn}) 554 * @param timeBetweenEvictionRunsMillis the amount of time (in milliseconds) to sleep between examining idle 555 * objects for eviction (see {@link #setTimeBetweenEvictionRunsMillis}) 556 * @param numTestsPerEvictionRun the number of idle objects to examine per run within the idle object eviction 557 * thread (if any) (see {@link #setNumTestsPerEvictionRun}) 558 * @param minEvictableIdleTimeMillis the minimum number of milliseconds an object can sit idle in the pool before 559 * it is eligible for eviction (see {@link #setMinEvictableIdleTimeMillis}) 560 * @param testWhileIdle whether or not to validate objects in the idle object eviction thread, if any 561 * (see {@link #setTestWhileIdle}) 562 * @param softMinEvictableIdleTimeMillis the minimum number of milliseconds an object can sit idle in the 563 * pool before it is eligible for eviction with the extra condition that at least "minIdle" amount of object 564 * remain in the pool. (see {@link #setSoftMinEvictableIdleTimeMillis}) 565 * @param lifo whether or not objects are returned in last-in-first-out order from the idle object pool 566 * (see {@link #setLifo}) 567 * @since Pool 1.4 568 */ 569 public GenericObjectPool(PoolableObjectFactory factory, int maxActive, byte whenExhaustedAction, long maxWait, 570 int maxIdle, int minIdle, boolean testOnBorrow, boolean testOnReturn, long timeBetweenEvictionRunsMillis, 571 int numTestsPerEvictionRun, long minEvictableIdleTimeMillis, boolean testWhileIdle, 572 long softMinEvictableIdleTimeMillis, boolean lifo) { 573 _factory = factory; 574 _maxActive = maxActive; 575 _lifo = lifo; 576 switch(whenExhaustedAction) { 577 case WHEN_EXHAUSTED_BLOCK: 578 case WHEN_EXHAUSTED_FAIL: 579 case WHEN_EXHAUSTED_GROW: 580 _whenExhaustedAction = whenExhaustedAction; 581 break; 582 default: 583 throw new IllegalArgumentException("whenExhaustedAction " + whenExhaustedAction + " not recognized."); 584 } 585 _maxWait = maxWait; 586 _maxIdle = maxIdle; 587 _minIdle = minIdle; 588 _testOnBorrow = testOnBorrow; 589 _testOnReturn = testOnReturn; 590 _timeBetweenEvictionRunsMillis = timeBetweenEvictionRunsMillis; 591 _numTestsPerEvictionRun = numTestsPerEvictionRun; 592 _minEvictableIdleTimeMillis = minEvictableIdleTimeMillis; 593 _softMinEvictableIdleTimeMillis = softMinEvictableIdleTimeMillis; 594 _testWhileIdle = testWhileIdle; 595 596 _pool = new CursorableLinkedList(); 597 startEvictor(_timeBetweenEvictionRunsMillis); 598 } 599 600 //--- public methods --------------------------------------------- 601 602 //--- configuration methods -------------------------------------- 603 604 /** 605 * Returns the maximum number of objects that can be allocated by the pool 606 * (checked out to clients, or idle awaiting checkout) at a given time. 607 * When non-positive, there is no limit to the number of objects that can 608 * be managed by the pool at one time. 609 * 610 * @return the cap on the total number of object instances managed by the pool. 611 * @see #setMaxActive 612 */ 613 public synchronized int getMaxActive() { 614 return _maxActive; 615 } 616 617 /** 618 * Sets the cap on the number of objects that can be allocated by the pool 619 * (checked out to clients, or idle awaiting checkout) at a given time. Use 620 * a negative value for no limit. 621 * 622 * @param maxActive The cap on the total number of object instances managed by the pool. 623 * Negative values mean that there is no limit to the number of objects allocated 624 * by the pool. 625 * @see #getMaxActive 626 */ 627 public void setMaxActive(int maxActive) { 628 synchronized(this) { 629 _maxActive = maxActive; 630 } 631 allocate(); 632 } 633 634 /** 635 * Returns the action to take when the {@link #borrowObject} method 636 * is invoked when the pool is exhausted (the maximum number 637 * of "active" objects has been reached). 638 * 639 * @return one of {@link #WHEN_EXHAUSTED_BLOCK}, {@link #WHEN_EXHAUSTED_FAIL} or {@link #WHEN_EXHAUSTED_GROW} 640 * @see #setWhenExhaustedAction 641 */ 642 public synchronized byte getWhenExhaustedAction() { 643 return _whenExhaustedAction; 644 } 645 646 /** 647 * Sets the action to take when the {@link #borrowObject} method 648 * is invoked when the pool is exhausted (the maximum number 649 * of "active" objects has been reached). 650 * 651 * @param whenExhaustedAction the action code, which must be one of 652 * {@link #WHEN_EXHAUSTED_BLOCK}, {@link #WHEN_EXHAUSTED_FAIL}, 653 * or {@link #WHEN_EXHAUSTED_GROW} 654 * @see #getWhenExhaustedAction 655 */ 656 public void setWhenExhaustedAction(byte whenExhaustedAction) { 657 synchronized(this) { 658 switch(whenExhaustedAction) { 659 case WHEN_EXHAUSTED_BLOCK: 660 case WHEN_EXHAUSTED_FAIL: 661 case WHEN_EXHAUSTED_GROW: 662 _whenExhaustedAction = whenExhaustedAction; 663 break; 664 default: 665 throw new IllegalArgumentException("whenExhaustedAction " + whenExhaustedAction + " not recognized."); 666 } 667 } 668 allocate(); 669 } 670 671 672 /** 673 * Returns the maximum amount of time (in milliseconds) the 674 * {@link #borrowObject} method should block before throwing 675 * an exception when the pool is exhausted and the 676 * {@link #setWhenExhaustedAction "when exhausted" action} is 677 * {@link #WHEN_EXHAUSTED_BLOCK}. 678 * 679 * When less than or equal to 0, the {@link #borrowObject} method 680 * may block indefinitely. 681 * 682 * @return maximum number of milliseconds to block when borrowing an object. 683 * @see #setMaxWait 684 * @see #setWhenExhaustedAction 685 * @see #WHEN_EXHAUSTED_BLOCK 686 */ 687 public synchronized long getMaxWait() { 688 return _maxWait; 689 } 690 691 /** 692 * Sets the maximum amount of time (in milliseconds) the 693 * {@link #borrowObject} method should block before throwing 694 * an exception when the pool is exhausted and the 695 * {@link #setWhenExhaustedAction "when exhausted" action} is 696 * {@link #WHEN_EXHAUSTED_BLOCK}. 697 * 698 * When less than or equal to 0, the {@link #borrowObject} method 699 * may block indefinitely. 700 * 701 * @param maxWait maximum number of milliseconds to block when borrowing an object. 702 * @see #getMaxWait 703 * @see #setWhenExhaustedAction 704 * @see #WHEN_EXHAUSTED_BLOCK 705 */ 706 public void setMaxWait(long maxWait) { 707 synchronized(this) { 708 _maxWait = maxWait; 709 } 710 allocate(); 711 } 712 713 /** 714 * Returns the cap on the number of "idle" instances in the pool. 715 * @return the cap on the number of "idle" instances in the pool. 716 * @see #setMaxIdle 717 */ 718 public synchronized int getMaxIdle() { 719 return _maxIdle; 720 } 721 722 /** 723 * Sets the cap on the number of "idle" instances in the pool. 724 * If maxIdle is set too low on heavily loaded systems it is possible you 725 * will see objects being destroyed and almost immediately new objects 726 * being created. This is a result of the active threads momentarily 727 * returning objects faster than they are requesting them them, causing the 728 * number of idle objects to rise above maxIdle. The best value for maxIdle 729 * for heavily loaded system will vary but the default is a good starting 730 * point. 731 * @param maxIdle The cap on the number of "idle" instances in the pool. 732 * Use a negative value to indicate an unlimited number of idle instances. 733 * @see #getMaxIdle 734 */ 735 public void setMaxIdle(int maxIdle) { 736 synchronized(this) { 737 _maxIdle = maxIdle; 738 } 739 allocate(); 740 } 741 742 /** 743 * Sets the minimum number of objects allowed in the pool 744 * before the evictor thread (if active) spawns new objects. 745 * Note that no objects are created when 746 * <code>numActive + numIdle >= maxActive.</code> 747 * This setting has no effect if the idle object evictor is disabled 748 * (i.e. if <code>timeBetweenEvictionRunsMillis <= 0</code>). 749 * 750 * @param minIdle The minimum number of objects. 751 * @see #getMinIdle 752 * @see #getTimeBetweenEvictionRunsMillis() 753 */ 754 public void setMinIdle(int minIdle) { 755 synchronized(this) { 756 _minIdle = minIdle; 757 } 758 allocate(); 759 } 760 761 /** 762 * Returns the minimum number of objects allowed in the pool 763 * before the evictor thread (if active) spawns new objects. 764 * (Note no objects are created when: numActive + numIdle >= maxActive) 765 * 766 * @return The minimum number of objects. 767 * @see #setMinIdle 768 */ 769 public synchronized int getMinIdle() { 770 return _minIdle; 771 } 772 773 /** 774 * When <tt>true</tt>, objects will be 775 * {@link PoolableObjectFactory#validateObject validated} 776 * before being returned by the {@link #borrowObject} 777 * method. If the object fails to validate, 778 * it will be dropped from the pool, and we will attempt 779 * to borrow another. 780 * 781 * @return <code>true</code> if objects are validated before being borrowed. 782 * @see #setTestOnBorrow 783 */ 784 public boolean getTestOnBorrow() { 785 return _testOnBorrow; 786 } 787 788 /** 789 * When <tt>true</tt>, objects will be 790 * {@link PoolableObjectFactory#validateObject validated} 791 * before being returned by the {@link #borrowObject} 792 * method. If the object fails to validate, 793 * it will be dropped from the pool, and we will attempt 794 * to borrow another. 795 * 796 * @param testOnBorrow <code>true</code> if objects should be validated before being borrowed. 797 * @see #getTestOnBorrow 798 */ 799 public void setTestOnBorrow(boolean testOnBorrow) { 800 _testOnBorrow = testOnBorrow; 801 } 802 803 /** 804 * When <tt>true</tt>, objects will be 805 * {@link PoolableObjectFactory#validateObject validated} 806 * before being returned to the pool within the 807 * {@link #returnObject}. 808 * 809 * @return <code>true</code> when objects will be validated after returned to {@link #returnObject}. 810 * @see #setTestOnReturn 811 */ 812 public boolean getTestOnReturn() { 813 return _testOnReturn; 814 } 815 816 /** 817 * When <tt>true</tt>, objects will be 818 * {@link PoolableObjectFactory#validateObject validated} 819 * before being returned to the pool within the 820 * {@link #returnObject}. 821 * 822 * @param testOnReturn <code>true</code> so objects will be validated after returned to {@link #returnObject}. 823 * @see #getTestOnReturn 824 */ 825 public void setTestOnReturn(boolean testOnReturn) { 826 _testOnReturn = testOnReturn; 827 } 828 829 /** 830 * Returns the number of milliseconds to sleep between runs of the 831 * idle object evictor thread. 832 * When non-positive, no idle object evictor thread will be 833 * run. 834 * 835 * @return number of milliseconds to sleep between evictor runs. 836 * @see #setTimeBetweenEvictionRunsMillis 837 */ 838 public synchronized long getTimeBetweenEvictionRunsMillis() { 839 return _timeBetweenEvictionRunsMillis; 840 } 841 842 /** 843 * Sets the number of milliseconds to sleep between runs of the 844 * idle object evictor thread. 845 * When non-positive, no idle object evictor thread will be 846 * run. 847 * 848 * @param timeBetweenEvictionRunsMillis number of milliseconds to sleep between evictor runs. 849 * @see #getTimeBetweenEvictionRunsMillis 850 */ 851 public synchronized void setTimeBetweenEvictionRunsMillis(long timeBetweenEvictionRunsMillis) { 852 _timeBetweenEvictionRunsMillis = timeBetweenEvictionRunsMillis; 853 startEvictor(_timeBetweenEvictionRunsMillis); 854 } 855 856 /** 857 * Returns the max number of objects to examine during each run of the 858 * idle object evictor thread (if any). 859 * 860 * @return max number of objects to examine during each evictor run. 861 * @see #setNumTestsPerEvictionRun 862 * @see #setTimeBetweenEvictionRunsMillis 863 */ 864 public synchronized int getNumTestsPerEvictionRun() { 865 return _numTestsPerEvictionRun; 866 } 867 868 /** 869 * Sets the max number of objects to examine during each run of the 870 * idle object evictor thread (if any). 871 * <p> 872 * When a negative value is supplied, <tt>ceil({@link #getNumIdle})/abs({@link #getNumTestsPerEvictionRun})</tt> 873 * tests will be run. That is, when the value is <i>-n</i>, roughly one <i>n</i>th of the 874 * idle objects will be tested per run. When the value is positive, the number of tests 875 * actually performed in each run will be the minimum of this value and the number of instances 876 * idle in the pool. 877 * 878 * @param numTestsPerEvictionRun max number of objects to examine during each evictor run. 879 * @see #getNumTestsPerEvictionRun 880 * @see #setTimeBetweenEvictionRunsMillis 881 */ 882 public synchronized void setNumTestsPerEvictionRun(int numTestsPerEvictionRun) { 883 _numTestsPerEvictionRun = numTestsPerEvictionRun; 884 } 885 886 /** 887 * Returns the minimum amount of time an object may sit idle in the pool 888 * before it is eligible for eviction by the idle object evictor 889 * (if any). 890 * 891 * @return minimum amount of time an object may sit idle in the pool before it is eligible for eviction. 892 * @see #setMinEvictableIdleTimeMillis 893 * @see #setTimeBetweenEvictionRunsMillis 894 */ 895 public synchronized long getMinEvictableIdleTimeMillis() { 896 return _minEvictableIdleTimeMillis; 897 } 898 899 /** 900 * Sets the minimum amount of time an object may sit idle in the pool 901 * before it is eligible for eviction by the idle object evictor 902 * (if any). 903 * When non-positive, no objects will be evicted from the pool 904 * due to idle time alone. 905 * @param minEvictableIdleTimeMillis minimum amount of time an object may sit idle in the pool before 906 * it is eligible for eviction. 907 * @see #getMinEvictableIdleTimeMillis 908 * @see #setTimeBetweenEvictionRunsMillis 909 */ 910 public synchronized void setMinEvictableIdleTimeMillis(long minEvictableIdleTimeMillis) { 911 _minEvictableIdleTimeMillis = minEvictableIdleTimeMillis; 912 } 913 914 /** 915 * Returns the minimum amount of time an object may sit idle in the pool 916 * before it is eligible for eviction by the idle object evictor 917 * (if any), with the extra condition that at least 918 * "minIdle" amount of object remain in the pool. 919 * 920 * @return minimum amount of time an object may sit idle in the pool before it is eligible for eviction. 921 * @since Pool 1.3 922 * @see #setSoftMinEvictableIdleTimeMillis 923 */ 924 public synchronized long getSoftMinEvictableIdleTimeMillis() { 925 return _softMinEvictableIdleTimeMillis; 926 } 927 928 /** 929 * Sets the minimum amount of time an object may sit idle in the pool 930 * before it is eligible for eviction by the idle object evictor 931 * (if any), with the extra condition that at least 932 * "minIdle" object instances remain in the pool. 933 * When non-positive, no objects will be evicted from the pool 934 * due to idle time alone. 935 * 936 * @param softMinEvictableIdleTimeMillis minimum amount of time an object may sit idle in the pool before 937 * it is eligible for eviction. 938 * @since Pool 1.3 939 * @see #getSoftMinEvictableIdleTimeMillis 940 */ 941 public synchronized void setSoftMinEvictableIdleTimeMillis(long softMinEvictableIdleTimeMillis) { 942 _softMinEvictableIdleTimeMillis = softMinEvictableIdleTimeMillis; 943 } 944 945 /** 946 * When <tt>true</tt>, objects will be 947 * {@link PoolableObjectFactory#validateObject validated} 948 * by the idle object evictor (if any). If an object 949 * fails to validate, it will be dropped from the pool. 950 * 951 * @return <code>true</code> when objects will be validated by the evictor. 952 * @see #setTestWhileIdle 953 * @see #setTimeBetweenEvictionRunsMillis 954 */ 955 public synchronized boolean getTestWhileIdle() { 956 return _testWhileIdle; 957 } 958 959 /** 960 * When <tt>true</tt>, objects will be 961 * {@link PoolableObjectFactory#validateObject validated} 962 * by the idle object evictor (if any). If an object 963 * fails to validate, it will be dropped from the pool. 964 * 965 * @param testWhileIdle <code>true</code> so objects will be validated by the evictor. 966 * @see #getTestWhileIdle 967 * @see #setTimeBetweenEvictionRunsMillis 968 */ 969 public synchronized void setTestWhileIdle(boolean testWhileIdle) { 970 _testWhileIdle = testWhileIdle; 971 } 972 973 /** 974 * Whether or not the idle object pool acts as a LIFO queue. True means 975 * that borrowObject returns the most recently used ("last in") idle object 976 * in the pool (if there are idle instances available). False means that 977 * the pool behaves as a FIFO queue - objects are taken from the idle object 978 * pool in the order that they are returned to the pool. 979 * 980 * @return <code>true</true> if the pool is configured to act as a LIFO queue 981 * @since 1.4 982 */ 983 public synchronized boolean getLifo() { 984 return _lifo; 985 } 986 987 /** 988 * Sets the LIFO property of the pool. True means that borrowObject returns 989 * the most recently used ("last in") idle object in the pool (if there are 990 * idle instances available). False means that the pool behaves as a FIFO 991 * queue - objects are taken from the idle object pool in the order that 992 * they are returned to the pool. 993 * 994 * @param lifo the new value for the LIFO property 995 * @since 1.4 996 */ 997 public synchronized void setLifo(boolean lifo) { 998 this._lifo = lifo; 999 } 1000 1001 /** 1002 * Sets my configuration. 1003 * 1004 * @param conf configuration to use. 1005 * @see GenericObjectPool.Config 1006 */ 1007 public void setConfig(GenericObjectPool.Config conf) { 1008 synchronized (this) { 1009 setMaxIdle(conf.maxIdle); 1010 setMinIdle(conf.minIdle); 1011 setMaxActive(conf.maxActive); 1012 setMaxWait(conf.maxWait); 1013 setWhenExhaustedAction(conf.whenExhaustedAction); 1014 setTestOnBorrow(conf.testOnBorrow); 1015 setTestOnReturn(conf.testOnReturn); 1016 setTestWhileIdle(conf.testWhileIdle); 1017 setNumTestsPerEvictionRun(conf.numTestsPerEvictionRun); 1018 setMinEvictableIdleTimeMillis(conf.minEvictableIdleTimeMillis); 1019 setTimeBetweenEvictionRunsMillis(conf.timeBetweenEvictionRunsMillis); 1020 setSoftMinEvictableIdleTimeMillis(conf.softMinEvictableIdleTimeMillis); 1021 setLifo(conf.lifo); 1022 } 1023 allocate(); 1024 } 1025 1026 //-- ObjectPool methods ------------------------------------------ 1027 1028 /** 1029 * <p>Borrows an object from the pool.</p> 1030 * 1031 * <p>If there is an idle instance available in the pool, then either the most-recently returned 1032 * (if {@link #getLifo() lifo} == true) or "oldest" (lifo == false) instance sitting idle in the pool 1033 * will be activated and returned. If activation fails, or {@link #getTestOnBorrow() testOnBorrow} is set 1034 * to true and validation fails, the instance is destroyed and the next available instance is examined. 1035 * This continues until either a valid instance is returned or there are no more idle instances available.</p> 1036 * 1037 * <p>If there are no idle instances available in the pool, behavior depends on the {@link #getMaxActive() maxActive} 1038 * and (if applicable) {@link #getWhenExhaustedAction() whenExhaustedAction} and {@link #getMaxWait() maxWait} 1039 * properties. If the number of instances checked out from the pool is less than <code>maxActive,</code> a new 1040 * instance is created, activated and (if applicable) validated and returned to the caller.</p> 1041 * 1042 * <p>If the pool is exhausted (no available idle instances and no capacity to create new ones), 1043 * this method will either block ({@link #WHEN_EXHAUSTED_BLOCK}), throw a <code>NoSuchElementException</code> 1044 * ({@link #WHEN_EXHAUSTED_FAIL}), or grow ({@link #WHEN_EXHAUSTED_GROW} - ignoring maxActive). 1045 * The length of time that this method will block when <code>whenExhaustedAction == WHEN_EXHAUSTED_BLOCK</code> 1046 * is determined by the {@link #getMaxWait() maxWait} property.</p> 1047 * 1048 * <p>When the pool is exhausted, multiple calling threads may be simultaneously blocked waiting for instances 1049 * to become available. As of pool 1.5, a "fairness" algorithm has been implemented to ensure that threads receive 1050 * available instances in request arrival order.</p> 1051 * 1052 * @return object instance 1053 * @throws NoSuchElementException if an instance cannot be returned 1054 */ 1055 public Object borrowObject() throws Exception { 1056 long starttime = System.currentTimeMillis(); 1057 Latch latch = new Latch(); 1058 byte whenExhaustedAction; 1059 long maxWait; 1060 synchronized (this) { 1061 // Get local copy of current config. Can't sync when used later as 1062 // it can result in a deadlock. Has the added advantage that config 1063 // is consistent for entire method execution 1064 whenExhaustedAction = _whenExhaustedAction; 1065 maxWait = _maxWait; 1066 1067 // Add this request to the queue 1068 _allocationQueue.add(latch); 1069 } 1070 // Work the allocation queue, allocating idle instances and 1071 // instance creation permits in request arrival order 1072 allocate(); 1073 1074 for(;;) { 1075 synchronized (this) { 1076 assertOpen(); 1077 } 1078 1079 // If no object was allocated from the pool above 1080 if(latch.getPair() == null) { 1081 // check if we were allowed to create one 1082 if(latch.mayCreate()) { 1083 // allow new object to be created 1084 } else { 1085 // the pool is exhausted 1086 switch(whenExhaustedAction) { 1087 case WHEN_EXHAUSTED_GROW: 1088 // allow new object to be created 1089 synchronized (this) { 1090 // Make sure another thread didn't allocate us an object 1091 // or permit a new object to be created 1092 if (latch.getPair() == null && !latch.mayCreate()) { 1093 _allocationQueue.remove(latch); 1094 _numInternalProcessing++; 1095 } 1096 } 1097 break; 1098 case WHEN_EXHAUSTED_FAIL: 1099 synchronized (this) { 1100 // Make sure allocate hasn't already assigned an object 1101 // in a different thread or permitted a new object to be created 1102 if (latch.getPair() != null || latch.mayCreate()) { 1103 break; 1104 } 1105 _allocationQueue.remove(latch); 1106 } 1107 throw new NoSuchElementException("Pool exhausted"); 1108 case WHEN_EXHAUSTED_BLOCK: 1109 try { 1110 synchronized (latch) { 1111 // Before we wait, make sure another thread didn't allocate us an object 1112 // or permit a new object to be created 1113 if (latch.getPair() == null && !latch.mayCreate()) { 1114 if(maxWait <= 0) { 1115 latch.wait(); 1116 } else { 1117 // this code may be executed again after a notify then continue cycle 1118 // so, need to calculate the amount of time to wait 1119 final long elapsed = (System.currentTimeMillis() - starttime); 1120 final long waitTime = maxWait - elapsed; 1121 if (waitTime > 0) 1122 { 1123 latch.wait(waitTime); 1124 } 1125 } 1126 } else { 1127 break; 1128 } 1129 } 1130 } catch(InterruptedException e) { 1131 boolean doAllocate = false; 1132 synchronized(this) { 1133 // Need to handle the all three possibilities 1134 if (latch.getPair() == null && !latch.mayCreate()) { 1135 // Case 1: latch still in allocation queue 1136 // Remove latch from the allocation queue 1137 _allocationQueue.remove(latch); 1138 } else if (latch.getPair() == null && latch.mayCreate()) { 1139 // Case 2: latch has been given permission to create 1140 // a new object 1141 _numInternalProcessing--; 1142 doAllocate = true; 1143 } else { 1144 // Case 3: An object has been allocated 1145 _numInternalProcessing--; 1146 _numActive++; 1147 returnObject(latch.getPair().getValue()); 1148 } 1149 } 1150 if (doAllocate) { 1151 allocate(); 1152 } 1153 Thread.currentThread().interrupt(); 1154 throw e; 1155 } 1156 if(maxWait > 0 && ((System.currentTimeMillis() - starttime) >= maxWait)) { 1157 synchronized(this) { 1158 // Make sure allocate hasn't already assigned an object 1159 // in a different thread or permitted a new object to be created 1160 if (latch.getPair() == null && !latch.mayCreate()) { 1161 // Remove latch from the allocation queue 1162 _allocationQueue.remove(latch); 1163 } else { 1164 break; 1165 } 1166 } 1167 throw new NoSuchElementException("Timeout waiting for idle object"); 1168 } else { 1169 continue; // keep looping 1170 } 1171 default: 1172 throw new IllegalArgumentException("WhenExhaustedAction property " + whenExhaustedAction + 1173 " not recognized."); 1174 } 1175 } 1176 } 1177 1178 boolean newlyCreated = false; 1179 if(null == latch.getPair()) { 1180 try { 1181 Object obj = _factory.makeObject(); 1182 latch.setPair(new ObjectTimestampPair(obj)); 1183 newlyCreated = true; 1184 } finally { 1185 if (!newlyCreated) { 1186 // object cannot be created 1187 synchronized (this) { 1188 _numInternalProcessing--; 1189 // No need to reset latch - about to throw exception 1190 } 1191 allocate(); 1192 } 1193 } 1194 } 1195 // activate & validate the object 1196 try { 1197 _factory.activateObject(latch.getPair().value); 1198 if(_testOnBorrow && 1199 !_factory.validateObject(latch.getPair().value)) { 1200 throw new Exception("ValidateObject failed"); 1201 } 1202 synchronized(this) { 1203 _numInternalProcessing--; 1204 _numActive++; 1205 } 1206 return latch.getPair().value; 1207 } 1208 catch (Throwable e) { 1209 PoolUtils.checkRethrow(e); 1210 // object cannot be activated or is invalid 1211 try { 1212 _factory.destroyObject(latch.getPair().value); 1213 } catch (Throwable e2) { 1214 PoolUtils.checkRethrow(e2); 1215 // cannot destroy broken object 1216 } 1217 synchronized (this) { 1218 _numInternalProcessing--; 1219 if (!newlyCreated) { 1220 latch.reset(); 1221 _allocationQueue.add(0, latch); 1222 } 1223 } 1224 allocate(); 1225 if(newlyCreated) { 1226 throw new NoSuchElementException("Could not create a validated object, cause: " + e.getMessage()); 1227 } 1228 else { 1229 continue; // keep looping 1230 } 1231 } 1232 } 1233 } 1234 1235 /** 1236 * Allocate available instances to latches in the allocation queue. Then 1237 * set _mayCreate to true for as many additional latches remaining in queue 1238 * as _maxActive allows. While it is safe for GOP, for consistency with GKOP 1239 * this method should not be called from inside a sync block. 1240 */ 1241 private synchronized void allocate() { 1242 if (isClosed()) return; 1243 1244 // First use any objects in the pool to clear the queue 1245 for (;;) { 1246 if (!_pool.isEmpty() && !_allocationQueue.isEmpty()) { 1247 Latch latch = (Latch) _allocationQueue.removeFirst(); 1248 latch.setPair((ObjectTimestampPair) _pool.removeFirst()); 1249 _numInternalProcessing++; 1250 synchronized (latch) { 1251 latch.notify(); 1252 } 1253 } else { 1254 break; 1255 } 1256 } 1257 1258 // Second utilise any spare capacity to create new objects 1259 for(;;) { 1260 if((!_allocationQueue.isEmpty()) && (_maxActive < 0 || (_numActive + _numInternalProcessing) < _maxActive)) { 1261 Latch latch = (Latch) _allocationQueue.removeFirst(); 1262 latch.setMayCreate(true); 1263 _numInternalProcessing++; 1264 synchronized (latch) { 1265 latch.notify(); 1266 } 1267 } else { 1268 break; 1269 } 1270 } 1271 } 1272 1273 /** 1274 * {@inheritDoc} 1275 * <p>Activation of this method decrements the active count and attempts to destroy the instance.</p> 1276 * 1277 * @throws Exception if the configured {@link PoolableObjectFactory} throws an exception destroying obj 1278 */ 1279 public void invalidateObject(Object obj) throws Exception { 1280 try { 1281 if (_factory != null) { 1282 _factory.destroyObject(obj); 1283 } 1284 } finally { 1285 synchronized (this) { 1286 _numActive--; 1287 } 1288 allocate(); 1289 } 1290 } 1291 1292 /** 1293 * Clears any objects sitting idle in the pool by removing them from the 1294 * idle instance pool and then invoking the configured 1295 * {@link PoolableObjectFactory#destroyObject(Object)} method on each idle 1296 * instance. 1297 * 1298 * <p> Implementation notes: 1299 * <ul><li>This method does not destroy or effect in any way instances that are 1300 * checked out of the pool when it is invoked.</li> 1301 * <li>Invoking this method does not prevent objects being 1302 * returned to the idle instance pool, even during its execution. It locks 1303 * the pool only during instance removal. Additional instances may be returned 1304 * while removed items are being destroyed.</li> 1305 * <li>Exceptions encountered destroying idle instances are swallowed.</li></ul></p> 1306 */ 1307 public void clear() { 1308 List toDestroy = new ArrayList(); 1309 1310 synchronized(this) { 1311 toDestroy.addAll(_pool); 1312 _numInternalProcessing = _numInternalProcessing + _pool._size; 1313 _pool.clear(); 1314 } 1315 destroy(toDestroy, _factory); 1316 } 1317 1318 /** 1319 * Private method to destroy all the objects in a collection using the 1320 * supplied object factory. Assumes that objects in the collection are 1321 * instances of ObjectTimestampPair and that the object instances that 1322 * they wrap were created by the factory. 1323 * 1324 * @param c Collection of objects to destroy 1325 * @param factory PoolableConnectionFactory used to destroy the objects 1326 */ 1327 private void destroy(Collection c, PoolableObjectFactory factory) { 1328 for (Iterator it = c.iterator(); it.hasNext();) { 1329 try { 1330 factory.destroyObject(((ObjectTimestampPair)(it.next())).value); 1331 } catch(Exception e) { 1332 // ignore error, keep destroying the rest 1333 } finally { 1334 synchronized(this) { 1335 _numInternalProcessing--; 1336 } 1337 allocate(); 1338 } 1339 } 1340 } 1341 1342 /** 1343 * Return the number of instances currently borrowed from this pool. 1344 * 1345 * @return the number of instances currently borrowed from this pool 1346 */ 1347 public synchronized int getNumActive() { 1348 return _numActive; 1349 } 1350 1351 /** 1352 * Return the number of instances currently idle in this pool. 1353 * 1354 * @return the number of instances currently idle in this pool 1355 */ 1356 public synchronized int getNumIdle() { 1357 return _pool.size(); 1358 } 1359 1360 /** 1361 * <p>Returns an object instance to the pool.</p> 1362 * 1363 * <p>If {@link #getMaxIdle() maxIdle} is set to a positive value and the number of idle instances 1364 * has reached this value, the returning instance is destroyed.</p> 1365 * 1366 * <p>If {@link #getTestOnReturn() testOnReturn} == true, the returning instance is validated before being returned 1367 * to the idle instance pool. In this case, if validation fails, the instance is destroyed.</p> 1368 * 1369 * <p><strong>Note: </strong> There is no guard to prevent an object 1370 * being returned to the pool multiple times. Clients are expected to 1371 * discard references to returned objects and ensure that an object is not 1372 * returned to the pool multiple times in sequence (i.e., without being 1373 * borrowed again between returns). Violating this contract will result in 1374 * the same object appearing multiple times in the pool and pool counters 1375 * (numActive, numIdle) returning incorrect values.</p> 1376 * 1377 * @param obj instance to return to the pool 1378 */ 1379 public void returnObject(Object obj) throws Exception { 1380 try { 1381 addObjectToPool(obj, true); 1382 } catch (Exception e) { 1383 if (_factory != null) { 1384 try { 1385 _factory.destroyObject(obj); 1386 } catch (Exception e2) { 1387 // swallowed 1388 } 1389 // TODO: Correctness here depends on control in addObjectToPool. 1390 // These two methods should be refactored, removing the 1391 // "behavior flag", decrementNumActive, from addObjectToPool. 1392 synchronized(this) { 1393 _numActive--; 1394 } 1395 allocate(); 1396 } 1397 } 1398 } 1399 1400 /** 1401 * <p>Adds an object to the pool.</p> 1402 * 1403 * <p>Validates the object if testOnReturn == true and passivates it before returning it to the pool. 1404 * if validation or passivation fails, or maxIdle is set and there is no room in the pool, the instance 1405 * is destroyed.</p> 1406 * 1407 * <p>Calls {@link #allocate()} on successful completion</p> 1408 * 1409 * @param obj instance to add to the pool 1410 * @param decrementNumActive whether or not to decrement the active count 1411 * @throws Exception 1412 */ 1413 private void addObjectToPool(Object obj, boolean decrementNumActive) throws Exception { 1414 boolean success = true; 1415 if(_testOnReturn && !(_factory.validateObject(obj))) { 1416 success = false; 1417 } else { 1418 _factory.passivateObject(obj); 1419 } 1420 1421 boolean shouldDestroy = !success; 1422 1423 // Add instance to pool if there is room and it has passed validation 1424 // (if testOnreturn is set) 1425 boolean doAllocate = false; 1426 synchronized (this) { 1427 if (isClosed()) { 1428 shouldDestroy = true; 1429 } else { 1430 if((_maxIdle >= 0) && (_pool.size() >= _maxIdle)) { 1431 shouldDestroy = true; 1432 } else if(success) { 1433 // borrowObject always takes the first element from the queue, 1434 // so for LIFO, push on top, FIFO add to end 1435 if (_lifo) { 1436 _pool.addFirst(new ObjectTimestampPair(obj)); 1437 } else { 1438 _pool.addLast(new ObjectTimestampPair(obj)); 1439 } 1440 if (decrementNumActive) { 1441 _numActive--; 1442 } 1443 doAllocate = true; 1444 } 1445 } 1446 } 1447 if (doAllocate) { 1448 allocate(); 1449 } 1450 1451 // Destroy the instance if necessary 1452 if(shouldDestroy) { 1453 try { 1454 _factory.destroyObject(obj); 1455 } catch(Exception e) { 1456 // ignored 1457 } 1458 // Decrement active count *after* destroy if applicable 1459 if (decrementNumActive) { 1460 synchronized(this) { 1461 _numActive--; 1462 } 1463 allocate(); 1464 } 1465 } 1466 1467 } 1468 1469 /** 1470 * <p>Closes the pool. Once the pool is closed, {@link #borrowObject()} 1471 * will fail with IllegalStateException, but {@link #returnObject(Object)} and 1472 * {@link #invalidateObject(Object)} will continue to work, with returned objects 1473 * destroyed on return.</p> 1474 * 1475 * <p>Destroys idle instances in the pool by invoking {@link #clear()}.</p> 1476 * 1477 * @throws Exception 1478 */ 1479 public void close() throws Exception { 1480 super.close(); 1481 synchronized (this) { 1482 clear(); 1483 startEvictor(-1L); 1484 } 1485 } 1486 1487 /** 1488 * Sets the {@link PoolableObjectFactory factory} this pool uses 1489 * to create new instances. Trying to change 1490 * the <code>factory</code> while there are borrowed objects will 1491 * throw an {@link IllegalStateException}. If there are instances idle 1492 * in the pool when this method is invoked, these will be destroyed 1493 * using the original factory. 1494 * 1495 * @param factory the {@link PoolableObjectFactory} used to create new instances. 1496 * @throws IllegalStateException when the factory cannot be set at this time 1497 * @deprecated to be removed in version 2.0 1498 */ 1499 public void setFactory(PoolableObjectFactory factory) throws IllegalStateException { 1500 List toDestroy = new ArrayList(); 1501 final PoolableObjectFactory oldFactory = _factory; 1502 synchronized (this) { 1503 assertOpen(); 1504 if(0 < getNumActive()) { 1505 throw new IllegalStateException("Objects are already active"); 1506 } else { 1507 toDestroy.addAll(_pool); 1508 _numInternalProcessing = _numInternalProcessing + _pool._size; 1509 _pool.clear(); 1510 } 1511 _factory = factory; 1512 } 1513 destroy(toDestroy, oldFactory); 1514 } 1515 1516 /** 1517 * <p>Perform <code>numTests</code> idle object eviction tests, evicting 1518 * examined objects that meet the criteria for eviction. If 1519 * <code>testWhileIdle</code> is true, examined objects are validated 1520 * when visited (and removed if invalid); otherwise only objects that 1521 * have been idle for more than <code>minEvicableIdletimeMillis</code> 1522 * are removed.</p> 1523 * 1524 * <p>Successive activations of this method examine objects in 1525 * in sequence, cycling through objects in oldest-to-youngest order.</p> 1526 * 1527 * @throws Exception if the pool is closed or eviction fails. 1528 */ 1529 public void evict() throws Exception { 1530 assertOpen(); 1531 synchronized (this) { 1532 if(_pool.isEmpty()) { 1533 return; 1534 } 1535 if (null == _evictionCursor) { 1536 _evictionCursor = (_pool.cursor(_lifo ? _pool.size() : 0)); 1537 } 1538 } 1539 1540 for (int i=0,m=getNumTests();i<m;i++) { 1541 final ObjectTimestampPair pair; 1542 synchronized (this) { 1543 if ((_lifo && !_evictionCursor.hasPrevious()) || 1544 !_lifo && !_evictionCursor.hasNext()) { 1545 _evictionCursor.close(); 1546 _evictionCursor = _pool.cursor(_lifo ? _pool.size() : 0); 1547 } 1548 1549 pair = _lifo ? 1550 (ObjectTimestampPair) _evictionCursor.previous() : 1551 (ObjectTimestampPair) _evictionCursor.next(); 1552 1553 _evictionCursor.remove(); 1554 _numInternalProcessing++; 1555 } 1556 1557 boolean removeObject = false; 1558 final long idleTimeMilis = System.currentTimeMillis() - pair.tstamp; 1559 if ((getMinEvictableIdleTimeMillis() > 0) && 1560 (idleTimeMilis > getMinEvictableIdleTimeMillis())) { 1561 removeObject = true; 1562 } else if ((getSoftMinEvictableIdleTimeMillis() > 0) && 1563 (idleTimeMilis > getSoftMinEvictableIdleTimeMillis()) && 1564 ((getNumIdle() + 1)> getMinIdle())) { // +1 accounts for object we are processing 1565 removeObject = true; 1566 } 1567 if(getTestWhileIdle() && !removeObject) { 1568 boolean active = false; 1569 try { 1570 _factory.activateObject(pair.value); 1571 active = true; 1572 } catch(Exception e) { 1573 removeObject=true; 1574 } 1575 if(active) { 1576 if(!_factory.validateObject(pair.value)) { 1577 removeObject=true; 1578 } else { 1579 try { 1580 _factory.passivateObject(pair.value); 1581 } catch(Exception e) { 1582 removeObject=true; 1583 } 1584 } 1585 } 1586 } 1587 1588 if (removeObject) { 1589 try { 1590 _factory.destroyObject(pair.value); 1591 } catch(Exception e) { 1592 // ignored 1593 } 1594 } 1595 synchronized (this) { 1596 if(!removeObject) { 1597 _evictionCursor.add(pair); 1598 if (_lifo) { 1599 // Skip over the element we just added back 1600 _evictionCursor.previous(); 1601 } 1602 } 1603 _numInternalProcessing--; 1604 } 1605 } 1606 allocate(); 1607 } 1608 1609 /** 1610 * Check to see if we are below our minimum number of objects 1611 * if so enough to bring us back to our minimum. 1612 * 1613 * @throws Exception when {@link #addObject()} fails. 1614 */ 1615 private void ensureMinIdle() throws Exception { 1616 // this method isn't synchronized so the 1617 // calculateDeficit is done at the beginning 1618 // as a loop limit and a second time inside the loop 1619 // to stop when another thread already returned the 1620 // needed objects 1621 int objectDeficit = calculateDeficit(false); 1622 for ( int j = 0 ; j < objectDeficit && calculateDeficit(true) > 0 ; j++ ) { 1623 try { 1624 addObject(); 1625 } finally { 1626 synchronized (this) { 1627 _numInternalProcessing--; 1628 } 1629 allocate(); 1630 } 1631 } 1632 } 1633 1634 /** 1635 * This returns the number of objects to create during the pool 1636 * sustain cycle. This will ensure that the minimum number of idle 1637 * instances is maintained without going past the maxActive value. 1638 * 1639 * @param incrementInternal - Should the count of objects currently under 1640 * some form of internal processing be 1641 * incremented? 1642 * @return The number of objects to be created 1643 */ 1644 private synchronized int calculateDeficit(boolean incrementInternal) { 1645 int objectDeficit = getMinIdle() - getNumIdle(); 1646 if (_maxActive > 0) { 1647 int growLimit = Math.max(0, 1648 getMaxActive() - getNumActive() - getNumIdle() - _numInternalProcessing); 1649 objectDeficit = Math.min(objectDeficit, growLimit); 1650 } 1651 if (incrementInternal && objectDeficit >0) { 1652 _numInternalProcessing++; 1653 } 1654 return objectDeficit; 1655 } 1656 1657 /** 1658 * Create an object, and place it into the pool. 1659 * addObject() is useful for "pre-loading" a pool with idle objects. 1660 */ 1661 public void addObject() throws Exception { 1662 assertOpen(); 1663 if (_factory == null) { 1664 throw new IllegalStateException("Cannot add objects without a factory."); 1665 } 1666 Object obj = _factory.makeObject(); 1667 try { 1668 assertOpen(); 1669 addObjectToPool(obj, false); 1670 } catch (IllegalStateException ex) { // Pool closed 1671 try { 1672 _factory.destroyObject(obj); 1673 } catch (Exception ex2) { 1674 // swallow 1675 } 1676 throw ex; 1677 } 1678 } 1679 1680 //--- non-public methods ---------------------------------------- 1681 1682 /** 1683 * Start the eviction thread or service, or when 1684 * <i>delay</i> is non-positive, stop it 1685 * if it is already running. 1686 * 1687 * @param delay milliseconds between evictor runs. 1688 */ 1689 protected synchronized void startEvictor(long delay) { 1690 if(null != _evictor) { 1691 EvictionTimer.cancel(_evictor); 1692 _evictor = null; 1693 } 1694 if(delay > 0) { 1695 _evictor = new Evictor(); 1696 EvictionTimer.schedule(_evictor, delay, delay); 1697 } 1698 } 1699 1700 /** 1701 * Returns pool info including {@link #getNumActive()}, {@link #getNumIdle()} 1702 * and a list of objects idle in the pool with their idle times. 1703 * 1704 * @return string containing debug information 1705 */ 1706 synchronized String debugInfo() { 1707 StringBuffer buf = new StringBuffer(); 1708 buf.append("Active: ").append(getNumActive()).append("\n"); 1709 buf.append("Idle: ").append(getNumIdle()).append("\n"); 1710 buf.append("Idle Objects:\n"); 1711 Iterator it = _pool.iterator(); 1712 long time = System.currentTimeMillis(); 1713 while(it.hasNext()) { 1714 ObjectTimestampPair pair = (ObjectTimestampPair)(it.next()); 1715 buf.append("\t").append(pair.value).append("\t").append(time - pair.tstamp).append("\n"); 1716 } 1717 return buf.toString(); 1718 } 1719 1720 /** 1721 * Returns the number of tests to be performed in an Evictor run, 1722 * based on the current value of <code>numTestsPerEvictionRun</code> 1723 * and the number of idle instances in the pool. 1724 * 1725 * @see #setNumTestsPerEvictionRun 1726 * @return the number of tests for the Evictor to run 1727 */ 1728 private int getNumTests() { 1729 if(_numTestsPerEvictionRun >= 0) { 1730 return Math.min(_numTestsPerEvictionRun, _pool.size()); 1731 } else { 1732 return(int)(Math.ceil(_pool.size()/Math.abs((double)_numTestsPerEvictionRun))); 1733 } 1734 } 1735 1736 //--- inner classes ---------------------------------------------- 1737 1738 /** 1739 * The idle object evictor {@link TimerTask}. 1740 * @see GenericObjectPool#setTimeBetweenEvictionRunsMillis 1741 */ 1742 private class Evictor extends TimerTask { 1743 /** 1744 * Run pool maintenance. Evict objects qualifying for eviction and then 1745 * invoke {@link GenericObjectPool#ensureMinIdle()}. 1746 */ 1747 public void run() { 1748 try { 1749 evict(); 1750 } catch(Exception e) { 1751 // ignored 1752 } catch(OutOfMemoryError oome) { 1753 // Log problem but give evictor thread a chance to continue in 1754 // case error is recoverable 1755 oome.printStackTrace(System.err); 1756 } 1757 try { 1758 ensureMinIdle(); 1759 } catch(Exception e) { 1760 // ignored 1761 } 1762 } 1763 } 1764 1765 /** 1766 * A simple "struct" encapsulating the 1767 * configuration information for a {@link GenericObjectPool}. 1768 * @see GenericObjectPool#GenericObjectPool(org.apache.commons.pool.PoolableObjectFactory, 1769 * org.apache.commons.pool.impl.GenericObjectPool.Config) 1770 * @see GenericObjectPool#setConfig 1771 */ 1772 public static class Config { 1773 //CHECKSTYLE: stop VisibilityModifier 1774 /** 1775 * @see GenericObjectPool#setMaxIdle 1776 */ 1777 public int maxIdle = GenericObjectPool.DEFAULT_MAX_IDLE; 1778 /** 1779 * @see GenericObjectPool#setMinIdle 1780 */ 1781 public int minIdle = GenericObjectPool.DEFAULT_MIN_IDLE; 1782 /** 1783 * @see GenericObjectPool#setMaxActive 1784 */ 1785 public int maxActive = GenericObjectPool.DEFAULT_MAX_ACTIVE; 1786 /** 1787 * @see GenericObjectPool#setMaxWait 1788 */ 1789 public long maxWait = GenericObjectPool.DEFAULT_MAX_WAIT; 1790 /** 1791 * @see GenericObjectPool#setWhenExhaustedAction 1792 */ 1793 public byte whenExhaustedAction = GenericObjectPool.DEFAULT_WHEN_EXHAUSTED_ACTION; 1794 /** 1795 * @see GenericObjectPool#setTestOnBorrow 1796 */ 1797 public boolean testOnBorrow = GenericObjectPool.DEFAULT_TEST_ON_BORROW; 1798 /** 1799 * @see GenericObjectPool#setTestOnReturn 1800 */ 1801 public boolean testOnReturn = GenericObjectPool.DEFAULT_TEST_ON_RETURN; 1802 /** 1803 * @see GenericObjectPool#setTestWhileIdle 1804 */ 1805 public boolean testWhileIdle = GenericObjectPool.DEFAULT_TEST_WHILE_IDLE; 1806 /** 1807 * @see GenericObjectPool#setTimeBetweenEvictionRunsMillis 1808 */ 1809 public long timeBetweenEvictionRunsMillis = GenericObjectPool.DEFAULT_TIME_BETWEEN_EVICTION_RUNS_MILLIS; 1810 /** 1811 * @see GenericObjectPool#setNumTestsPerEvictionRun 1812 */ 1813 public int numTestsPerEvictionRun = GenericObjectPool.DEFAULT_NUM_TESTS_PER_EVICTION_RUN; 1814 /** 1815 * @see GenericObjectPool#setMinEvictableIdleTimeMillis 1816 */ 1817 public long minEvictableIdleTimeMillis = GenericObjectPool.DEFAULT_MIN_EVICTABLE_IDLE_TIME_MILLIS; 1818 /** 1819 * @see GenericObjectPool#setSoftMinEvictableIdleTimeMillis 1820 */ 1821 public long softMinEvictableIdleTimeMillis = GenericObjectPool.DEFAULT_SOFT_MIN_EVICTABLE_IDLE_TIME_MILLIS; 1822 /** 1823 * @see GenericObjectPool#setLifo 1824 */ 1825 public boolean lifo = GenericObjectPool.DEFAULT_LIFO; 1826 //CHECKSTYLE: resume VisibilityModifier 1827 } 1828 1829 /** 1830 * Latch used to control allocation order of objects to threads to ensure 1831 * fairness. That is, objects are allocated to threads in the order that 1832 * threads request objects. 1833 */ 1834 private static final class Latch { 1835 1836 /** object timestamp pair allocated to this latch */ 1837 private ObjectTimestampPair _pair; 1838 1839 /** Whether or not this latch may create an object instance */ 1840 private boolean _mayCreate = false; 1841 1842 /** 1843 * Returns ObjectTimestampPair allocated to this latch 1844 * @return ObjectTimestampPair allocated to this latch 1845 */ 1846 private synchronized ObjectTimestampPair getPair() { 1847 return _pair; 1848 } 1849 1850 /** 1851 * Sets ObjectTimestampPair on this latch 1852 * @param pair ObjectTimestampPair allocated to this latch 1853 */ 1854 private synchronized void setPair(ObjectTimestampPair pair) { 1855 _pair = pair; 1856 } 1857 1858 /** 1859 * Whether or not this latch may create an object instance 1860 * @return true if this latch has an instance creation permit 1861 */ 1862 private synchronized boolean mayCreate() { 1863 return _mayCreate; 1864 } 1865 1866 /** 1867 * Sets the mayCreate property 1868 * @param mayCreate new value for mayCreate 1869 */ 1870 private synchronized void setMayCreate(boolean mayCreate) { 1871 _mayCreate = mayCreate; 1872 } 1873 1874 /** 1875 * Reset the latch data. Used when an allocation fails and the latch 1876 * needs to be re-added to the queue. 1877 */ 1878 private synchronized void reset() { 1879 _pair = null; 1880 _mayCreate = false; 1881 } 1882 } 1883 1884 1885 //--- private attributes --------------------------------------- 1886 1887 /** 1888 * The cap on the number of idle instances in the pool. 1889 * @see #setMaxIdle 1890 * @see #getMaxIdle 1891 */ 1892 private int _maxIdle = DEFAULT_MAX_IDLE; 1893 1894 /** 1895 * The cap on the minimum number of idle instances in the pool. 1896 * @see #setMinIdle 1897 * @see #getMinIdle 1898 */ 1899 private int _minIdle = DEFAULT_MIN_IDLE; 1900 1901 /** 1902 * The cap on the total number of active instances from the pool. 1903 * @see #setMaxActive 1904 * @see #getMaxActive 1905 */ 1906 private int _maxActive = DEFAULT_MAX_ACTIVE; 1907 1908 /** 1909 * The maximum amount of time (in millis) the 1910 * {@link #borrowObject} method should block before throwing 1911 * an exception when the pool is exhausted and the 1912 * {@link #getWhenExhaustedAction "when exhausted" action} is 1913 * {@link #WHEN_EXHAUSTED_BLOCK}. 1914 * 1915 * When less than or equal to 0, the {@link #borrowObject} method 1916 * may block indefinitely. 1917 * 1918 * @see #setMaxWait 1919 * @see #getMaxWait 1920 * @see #WHEN_EXHAUSTED_BLOCK 1921 * @see #setWhenExhaustedAction 1922 * @see #getWhenExhaustedAction 1923 */ 1924 private long _maxWait = DEFAULT_MAX_WAIT; 1925 1926 /** 1927 * The action to take when the {@link #borrowObject} method 1928 * is invoked when the pool is exhausted (the maximum number 1929 * of "active" objects has been reached). 1930 * 1931 * @see #WHEN_EXHAUSTED_BLOCK 1932 * @see #WHEN_EXHAUSTED_FAIL 1933 * @see #WHEN_EXHAUSTED_GROW 1934 * @see #DEFAULT_WHEN_EXHAUSTED_ACTION 1935 * @see #setWhenExhaustedAction 1936 * @see #getWhenExhaustedAction 1937 */ 1938 private byte _whenExhaustedAction = DEFAULT_WHEN_EXHAUSTED_ACTION; 1939 1940 /** 1941 * When <tt>true</tt>, objects will be 1942 * {@link PoolableObjectFactory#validateObject validated} 1943 * before being returned by the {@link #borrowObject} 1944 * method. If the object fails to validate, 1945 * it will be dropped from the pool, and we will attempt 1946 * to borrow another. 1947 * 1948 * @see #setTestOnBorrow 1949 * @see #getTestOnBorrow 1950 */ 1951 private volatile boolean _testOnBorrow = DEFAULT_TEST_ON_BORROW; 1952 1953 /** 1954 * When <tt>true</tt>, objects will be 1955 * {@link PoolableObjectFactory#validateObject validated} 1956 * before being returned to the pool within the 1957 * {@link #returnObject}. 1958 * 1959 * @see #getTestOnReturn 1960 * @see #setTestOnReturn 1961 */ 1962 private volatile boolean _testOnReturn = DEFAULT_TEST_ON_RETURN; 1963 1964 /** 1965 * When <tt>true</tt>, objects will be 1966 * {@link PoolableObjectFactory#validateObject validated} 1967 * by the idle object evictor (if any). If an object 1968 * fails to validate, it will be dropped from the pool. 1969 * 1970 * @see #setTestWhileIdle 1971 * @see #getTestWhileIdle 1972 * @see #getTimeBetweenEvictionRunsMillis 1973 * @see #setTimeBetweenEvictionRunsMillis 1974 */ 1975 private boolean _testWhileIdle = DEFAULT_TEST_WHILE_IDLE; 1976 1977 /** 1978 * The number of milliseconds to sleep between runs of the 1979 * idle object evictor thread. 1980 * When non-positive, no idle object evictor thread will be 1981 * run. 1982 * 1983 * @see #setTimeBetweenEvictionRunsMillis 1984 * @see #getTimeBetweenEvictionRunsMillis 1985 */ 1986 private long _timeBetweenEvictionRunsMillis = DEFAULT_TIME_BETWEEN_EVICTION_RUNS_MILLIS; 1987 1988 /** 1989 * The max number of objects to examine during each run of the 1990 * idle object evictor thread (if any). 1991 * <p> 1992 * When a negative value is supplied, <tt>ceil({@link #getNumIdle})/abs({@link #getNumTestsPerEvictionRun})</tt> 1993 * tests will be run. I.e., when the value is <i>-n</i>, roughly one <i>n</i>th of the 1994 * idle objects will be tested per run. 1995 * 1996 * @see #setNumTestsPerEvictionRun 1997 * @see #getNumTestsPerEvictionRun 1998 * @see #getTimeBetweenEvictionRunsMillis 1999 * @see #setTimeBetweenEvictionRunsMillis 2000 */ 2001 private int _numTestsPerEvictionRun = DEFAULT_NUM_TESTS_PER_EVICTION_RUN; 2002 2003 /** 2004 * The minimum amount of time an object may sit idle in the pool 2005 * before it is eligible for eviction by the idle object evictor 2006 * (if any). 2007 * When non-positive, no objects will be evicted from the pool 2008 * due to idle time alone. 2009 * 2010 * @see #setMinEvictableIdleTimeMillis 2011 * @see #getMinEvictableIdleTimeMillis 2012 * @see #getTimeBetweenEvictionRunsMillis 2013 * @see #setTimeBetweenEvictionRunsMillis 2014 */ 2015 private long _minEvictableIdleTimeMillis = DEFAULT_MIN_EVICTABLE_IDLE_TIME_MILLIS; 2016 2017 /** 2018 * The minimum amount of time an object may sit idle in the pool 2019 * before it is eligible for eviction by the idle object evictor 2020 * (if any), with the extra condition that at least 2021 * "minIdle" amount of object remain in the pool. 2022 * When non-positive, no objects will be evicted from the pool 2023 * due to idle time alone. 2024 * 2025 * @see #setSoftMinEvictableIdleTimeMillis 2026 * @see #getSoftMinEvictableIdleTimeMillis 2027 */ 2028 private long _softMinEvictableIdleTimeMillis = DEFAULT_SOFT_MIN_EVICTABLE_IDLE_TIME_MILLIS; 2029 2030 /** Whether or not the pool behaves as a LIFO queue (last in first out) */ 2031 private boolean _lifo = DEFAULT_LIFO; 2032 2033 /** My pool. */ 2034 private CursorableLinkedList _pool = null; 2035 2036 /** Eviction cursor - keeps track of idle object evictor position */ 2037 private CursorableLinkedList.Cursor _evictionCursor = null; 2038 2039 /** My {@link PoolableObjectFactory}. */ 2040 private PoolableObjectFactory _factory = null; 2041 2042 /** 2043 * The number of objects {@link #borrowObject} borrowed 2044 * from the pool, but not yet returned. 2045 */ 2046 private int _numActive = 0; 2047 2048 /** 2049 * My idle object eviction {@link TimerTask}, if any. 2050 */ 2051 private Evictor _evictor = null; 2052 2053 /** 2054 * The number of objects subject to some form of internal processing 2055 * (usually creation or destruction) that should be included in the total 2056 * number of objects but are neither active nor idle. 2057 */ 2058 private int _numInternalProcessing = 0; 2059 2060 /** 2061 * Used to track the order in which threads call {@link #borrowObject()} so 2062 * that objects can be allocated in the order in which the threads requested 2063 * them. 2064 */ 2065 private final LinkedList _allocationQueue = new LinkedList(); 2066 2067 }