com.nabla.wapp.server.database.CommonConnectionPool.java Source code

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Here is the source code for com.nabla.wapp.server.database.CommonConnectionPool.java

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/**
* Copyright 2012 nabla
*
* Licensed 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 com.nabla.wapp.server.database;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

import javax.servlet.ServletContext;

import org.apache.commons.dbcp.PoolingDriver;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.commons.pool.impl.GenericObjectPool;

import com.nabla.wapp.server.general.Assert;

public class CommonConnectionPool implements IConnectionPool {

    public static final String DATABASE_DRIVER_NAME = "database_driver_name";
    private static final Log log = LogFactory.getLog(CommonConnectionPool.class);
    private static final PoolingDriver driver = new PoolingDriver();
    private final String url;

    /**
     * Constructor
     * @param dbName         - database name as defined in pool
     * @param serverContext      - web app context
     * @throws SQLException 
     */
    public CommonConnectionPool(final String dbName, final ServletContext serverContext) throws SQLException {
        Assert.argumentNotNull(dbName, "Have you set the database name in your web.xml file?");
        Assert.argumentNotNull(serverContext);

        url = "jdbc:apache:commons:dbcp:/" + dbName;
        if (!isLoaded(dbName)) {
            load(dbName);
            final String driverName = serverContext.getInitParameter(DATABASE_DRIVER_NAME);
            Assert.notNull(driverName, "Have you set the database driver name in your web.xml file?");
            try {
                Class.forName(driverName);
            } catch (ClassNotFoundException e) {
                if (log.isDebugEnabled())
                    log.debug("fail to find database driver class '" + driverName + "'", e);
                throw new SQLException("fail to find database driver class '" + driverName + "'");
            }
        }
    }

    @Override
    public Connection get() throws SQLException {
        return DriverManager.getConnection(url);
    }

    /**
     * Load database pool
     * @param name - database name as defined in pool
     */
    public static void load(final String name) {
        if (log.isDebugEnabled())
            log.debug("loading pool for database '" + name + "'");
        driver.registerPool(name, new GenericObjectPool(null));
    }

    /*
       public static void unload(final String name) {
          if (log.isDebugEnabled())
     log.debug("unloading pool for database '" + name + "'");
          try {
     driver.closePool(name);
          } catch (final SQLException e) {}
       }
        
       public static void unloadAll() {
          final String[] names = driver.getPoolNames();
          if (names != null) {
     for (final String name : names)
        unload(name);
          }
       }
    */
    public static boolean isLoaded(final String name) {
        final String[] names = driver.getPoolNames();
        if (names == null)
            return false;
        for (final String n : names) {
            if (n.compareTo(name) == 0)
                return true;
        }
        return false;
    }

}