| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package org.apache.commons.pool; |
| |
| /** |
| * An interface defining life-cycle methods for |
| * instances to be served by a {@link KeyedObjectPool}. |
| * <p> |
| * By contract, when an {@link KeyedObjectPool} |
| * delegates to a {@link KeyedPoolableObjectFactory}, |
| * <ol> |
| * <li> |
| * {@link #makeObject makeObject} |
| * is called whenever a new instance is needed. |
| * </li> |
| * <li> |
| * {@link #activateObject activateObject} |
| * is invoked on every instance that has been |
| * {@link #passivateObject passivated} before it is |
| * {@link KeyedObjectPool#borrowObject borrowed} from the pool. |
| * </li> |
| * <li> |
| * {@link #validateObject validateObject} |
| * is invoked on {@link #activateObject activated} instances to make sure |
| * they can be {@link KeyedObjectPool#borrowObject borrowed} from the pool. |
| * <code>validateObject</code> <strong>may</strong> also be used to test an |
| * instance being {@link KeyedObjectPool#returnObject returned} to the pool |
| * before it is {@link #passivateObject passivated}. It will only be invoked |
| * on an activated instance. |
| * </li> |
| * <li> |
| * {@link #passivateObject passivateObject} |
| * is invoked on every instance when it is returned to the pool. |
| * </li> |
| * <li> |
| * {@link #destroyObject destroyObject} |
| * is invoked on every instance when it is being "dropped" from the |
| * pool (whether due to the response from <code>validateObject</code>, |
| * or for reasons specific to the pool implementation.) There is no |
| * guarantee that the instance being destroyed will |
| * be considered active, passive or in a generally consistent state. |
| * </li> |
| * </ol> |
| * </p> |
| * <p> |
| * {@link KeyedPoolableObjectFactory} must be thread-safe. The only promise |
| * an {@link KeyedObjectPool} makes is that the same instance of an object will not |
| * be passed to more than one method of a <code>KeyedPoolableObjectFactory</code> |
| * at a time. |
| * </p> |
| * |
| * @see KeyedObjectPool |
| * |
| * @author Rodney Waldhoff |
| * @author Sandy McArthur |
| * @version $Revision$ $Date$ |
| * @since Pool 1.0 |
| */ |
| public interface KeyedPoolableObjectFactory { |
| /** |
| * Create an instance that can be served by the pool. |
| * Instances returned from this method should be in the |
| * same state as if they had been |
| * {@link #activateObject activated}. They will not be |
| * activated before being served by the pool. |
| * |
| * @param key the key used when constructing the object |
| * @return an instance that can be served by the pool. |
| * @throws Exception if there is a problem creating a new instance, |
| * this will be propagated to the code requesting an object. |
| */ |
| Object makeObject(Object key) throws Exception; |
| |
| /** |
| * Destroy an instance no longer needed by the pool. |
| * <p> |
| * It is important for implementations of this method to be aware |
| * that there is no guarantee about what state <code>obj</code> |
| * will be in and the implementation should be prepared to handle |
| * unexpected errors. |
| * </p> |
| * <p> |
| * Also, an implementation must take in to consideration that |
| * instances lost to the garbage collector may never be destroyed. |
| * </p> |
| * |
| * @param key the key used when selecting the instance |
| * @param obj the instance to be destroyed |
| * @throws Exception should be avoided as it may be swallowed by |
| * the pool implementation. |
| * @see #validateObject |
| * @see KeyedObjectPool#invalidateObject |
| */ |
| void destroyObject(Object key, Object obj) throws Exception; |
| |
| /** |
| * Ensures that the instance is safe to be returned by the pool. |
| * Returns <code>false</code> if <code>obj</code> should be destroyed. |
| * |
| * @param key the key used when selecting the object |
| * @param obj the instance to be validated |
| * @return <code>false</code> if <code>obj</code> is not valid and should |
| * be dropped from the pool, <code>true</code> otherwise. |
| */ |
| boolean validateObject(Object key, Object obj); |
| |
| /** |
| * Reinitialize an instance to be returned by the pool. |
| * |
| * @param key the key used when selecting the object |
| * @param obj the instance to be activated |
| * @throws Exception if there is a problem activating <code>obj</code>, |
| * this exception may be swallowed by the pool. |
| * @see #destroyObject |
| */ |
| void activateObject(Object key, Object obj) throws Exception; |
| |
| /** |
| * Uninitialize an instance to be returned to the idle object pool. |
| * |
| * @param key the key used when selecting the object |
| * @param obj the instance to be passivated |
| * @throws Exception if there is a problem passivating <code>obj</code>, |
| * this exception may be swallowed by the pool. |
| * @see #destroyObject |
| */ |
| void passivateObject(Object key, Object obj) throws Exception; |
| } |