/* * 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.
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/** * <p> * Database Connection Pool API. * </p> * * <b>Overview in Dialog Form</b> * <p> * Q: How do I use the DBCP package? * </p> * <p> * A: There are two primary ways to access the DBCP pool, as a {@link java.sql.Driver Driver}, or as a * {@link javax.sql.DataSource DataSource}. You'll want to create an instance of * {@link org.apache.tomcat.dbcp.dbcp2.PoolingDriver} or {@link org.apache.tomcat.dbcp.dbcp2.PoolingDataSource}. When using one * of these interfaces, you can just use your JDBC objects the way you normally would. Closing a * {@link java.sql.Connection} will simply return it to its pool. * </p> * <p> * Q: But {@link org.apache.tomcat.dbcp.dbcp2.PoolingDriver PoolingDriver} and * {@link org.apache.tomcat.dbcp.dbcp2.PoolingDataSource PoolingDataSource} both expect an * {@link org.apache.tomcat.dbcp.pool2.ObjectPool ObjectPool} as an input. Where do I get one of those? * </p> * <p> * A: The {@link org.apache.tomcat.dbcp.pool2.ObjectPool ObjectPool} interface is defined in Commons Pool. You can use one * of the provided implementations such as {@link org.apache.tomcat.dbcp.pool2.impl.GenericObjectPool GenericObjectPool} or * {@link org.apache.tomcat.dbcp.pool2.impl.SoftReferenceObjectPool SoftReferenceObjectPool} or you can create your own. * </p> * <p> * Q: Ok, I've found an {@link org.apache.tomcat.dbcp.pool2.ObjectPool ObjectPool} implementation that I think suits my * connection pooling needs. But it wants a {@link org.apache.tomcat.dbcp.pool2.PooledObjectFactory PooledObjectFactory}. * What should I use for that? * </p> * <p> * A: The DBCP package provides a class for this purpose. It's called * {@link org.apache.tomcat.dbcp.dbcp2.PoolableConnectionFactory}. It implements the factory and lifecycle methods of * {@link org.apache.tomcat.dbcp.pool2.PooledObjectFactory} for {@link java.sql.Connection}s. But it doesn't create the * actual database {@link java.sql.Connection}s itself, it uses a {@link org.apache.tomcat.dbcp.dbcp2.ConnectionFactory} for * that. The {@link org.apache.tomcat.dbcp.dbcp2.PoolableConnectionFactory} will take {@link java.sql.Connection}s created * by the {@link org.apache.tomcat.dbcp.dbcp2.ConnectionFactory} and wrap them with classes that implement the pooling * behaviour. * </p> * <p> * Several implementations of {@link org.apache.tomcat.dbcp.dbcp2.ConnectionFactory} are provided--one that uses * {@link java.sql.DriverManager} to create connections * ({@link org.apache.tomcat.dbcp.dbcp2.DriverManagerConnectionFactory}), one that uses a {@link java.sql.Driver} to create * connections ({@link org.apache.tomcat.dbcp.dbcp2.DriverConnectionFactory}), one that uses a {@link javax.sql.DataSource} * to create connections ({@link org.apache.tomcat.dbcp.dbcp2.DataSourceConnectionFactory}). * </p> * <p> * Q: I think I'm starting to get it, but can you walk me though it again? * </p> * <p> * A: Sure. Let's assume you want to create a {@link javax.sql.DataSource} that pools {@link java.sql.Connection}s. * Let's also assume that those pooled {@link java.sql.Connection}s should be obtained from the * {@link java.sql.DriverManager}. You'll want to create a {@link org.apache.tomcat.dbcp.dbcp2.PoolingDataSource}. * </p> * <p> * The {@link org.apache.tomcat.dbcp.dbcp2.PoolingDataSource} uses an underlying {@link org.apache.tomcat.dbcp.pool2.ObjectPool} * to create and store its {@link java.sql.Connection}. * </p> * <p> * To create a {@link org.apache.tomcat.dbcp.pool2.ObjectPool}, you'll need a * {@link org.apache.tomcat.dbcp.pool2.PooledObjectFactory} that creates the actual {@link java.sql.Connection}s. That's * what {@link org.apache.tomcat.dbcp.dbcp2.PoolableConnectionFactory} is for. * </p> * <p> * To create the {@link org.apache.tomcat.dbcp.dbcp2.PoolableConnectionFactory}, you'll need at least two things: * </p> * <ol> * <li>A {@link org.apache.tomcat.dbcp.dbcp2.ConnectionFactory} from which the actual database {@link java.sql.Connection}s * will be obtained.</li> * <li>An empty and factory-less {@link org.apache.tomcat.dbcp.pool2.ObjectPool} in which the {@link java.sql.Connection}s * will be stored. <br> * When you pass an {@link org.apache.tomcat.dbcp.pool2.ObjectPool} into the * {@link org.apache.tomcat.dbcp.dbcp2.PoolableConnectionFactory}, it will automatically register itself as the * {@link org.apache.tomcat.dbcp.pool2.PooledObjectFactory} for that pool.</li> * </ol> * <p> * In code, that might look like this: * </p> * * <pre> * GenericObjectPool connectionPool = new GenericObjectPool(null); * ConnectionFactory connectionFactory = new DriverManagerConnectionFactory("jdbc:some:connect:string", "userName", * "password"); * PoolableConnectionFactory poolableConnectionFactory = new PoolableConnectionFactory(connectionFactory, * connectionPool, null, null, false, true); * PoolingDataSource dataSource = new PoolingDataSource(connectionPool); * </pre> * <p> * To create a {@link org.apache.tomcat.dbcp.dbcp2.PoolingDriver}, we do the same thing, except that instead of creating a * {@link javax.sql.DataSource} on the last line, we create a {@link org.apache.tomcat.dbcp.dbcp2.PoolingDriver}, and * register the {@code connectionPool} with it. E.g.,: * </p> * * <pre> * GenericObjectPool connectionPool = new GenericObjectPool(null); * ConnectionFactory connectionFactory = new DriverManagerConnectionFactory("jdbc:some:connect:string", "userName", * "password"); * PoolableConnectionFactory poolableConnectionFactory = new PoolableConnectionFactory(connectionFactory, * connectionPool, null, null, false, true); * PoolingDriver driver = new PoolingDriver(); * driver.registerPool("example", connectionPool); * </pre> * <p> * Since the {@link org.apache.tomcat.dbcp.dbcp2.PoolingDriver} registers itself with the {@link java.sql.DriverManager} * when it is created, now you can just go to the {@link java.sql.DriverManager} to create your * {@link java.sql.Connection}s, like you normally would: * </p> * * <pre> * Connection conn = DriverManager.getConnection("jdbc:apache:commons:dbcp:example"); * </pre>
*/ package org.apache.tomcat.dbcp.dbcp2;
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