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Commons DBCP example source code file (SharedPoolDataSource.java)
This example Commons DBCP source code file (SharedPoolDataSource.java) is included in the DevDaily.com
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The Commons DBCP SharedPoolDataSource.java source code
/*
* 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.dbcp.datasources;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.sql.Connection;
import java.sql.SQLException;
import javax.naming.NamingException;
import javax.naming.Reference;
import javax.naming.StringRefAddr;
import javax.sql.ConnectionPoolDataSource;
import org.apache.commons.pool.KeyedObjectPool;
import org.apache.commons.pool.impl.GenericKeyedObjectPool;
import org.apache.commons.pool.impl.GenericObjectPool;
import org.apache.commons.dbcp.SQLNestedException;
/**
* <p>A pooling DataSource appropriate for deployment within
* J2EE environment. There are many configuration options, most of which are
* defined in the parent class. All users (based on username) share a single
* maximum number of Connections in this datasource.</p>
*
* <p>User passwords can be changed without re-initializing the datasource.
* When a <code>getConnection(username, password) request is processed
* with a password that is different from those used to create connections in the
* pool associated with <code>username, an attempt is made to create a
* new connection using the supplied password and if this succeeds, idle connections
* created using the old password are destroyed and new connections are created
* using the new password.</p>
*
* @author John D. McNally
* @version $Revision: 907288 $ $Date: 2010-02-06 14:42:58 -0500 (Sat, 06 Feb 2010) $
*/
public class SharedPoolDataSource
extends InstanceKeyDataSource {
private static final long serialVersionUID = -8132305535403690372L;
private int maxActive = GenericObjectPool.DEFAULT_MAX_ACTIVE;
private int maxIdle = GenericObjectPool.DEFAULT_MAX_IDLE;
private int maxWait = (int)Math.min(Integer.MAX_VALUE,
GenericObjectPool.DEFAULT_MAX_WAIT);
private transient KeyedObjectPool pool = null;
private transient KeyedCPDSConnectionFactory factory = null;
/**
* Default no-arg constructor for Serialization
*/
public SharedPoolDataSource() {
}
/**
* Close pool being maintained by this datasource.
*/
public void close() throws Exception {
if (pool != null) {
pool.close();
}
InstanceKeyObjectFactory.removeInstance(instanceKey);
}
// -------------------------------------------------------------------
// Properties
/**
* The maximum number of active connections that can be allocated from
* this pool at the same time, or non-positive for no limit.
*/
public int getMaxActive() {
return (this.maxActive);
}
/**
* The maximum number of active connections that can be allocated from
* this pool at the same time, or non-positive for no limit.
* The default is 8.
*/
public void setMaxActive(int maxActive) {
assertInitializationAllowed();
this.maxActive = maxActive;
}
/**
* The maximum number of active connections that can remain idle in the
* pool, without extra ones being released, or negative for no limit.
*/
public int getMaxIdle() {
return (this.maxIdle);
}
/**
* The maximum number of active connections that can remain idle in the
* pool, without extra ones being released, or negative for no limit.
* The default is 8.
*/
public void setMaxIdle(int maxIdle) {
assertInitializationAllowed();
this.maxIdle = maxIdle;
}
/**
* The maximum number of milliseconds that the pool will wait (when there
* are no available connections) for a connection to be returned before
* throwing an exception, or -1 to wait indefinitely. Will fail
* immediately if value is 0.
* The default is -1.
*/
public int getMaxWait() {
return (this.maxWait);
}
/**
* The maximum number of milliseconds that the pool will wait (when there
* are no available connections) for a connection to be returned before
* throwing an exception, or -1 to wait indefinitely. Will fail
* immediately if value is 0.
* The default is -1.
*/
public void setMaxWait(int maxWait) {
assertInitializationAllowed();
this.maxWait = maxWait;
}
// ----------------------------------------------------------------------
// Instrumentation Methods
/**
* Get the number of active connections in the pool.
*/
public int getNumActive() {
return (pool == null) ? 0 : pool.getNumActive();
}
/**
* Get the number of idle connections in the pool.
*/
public int getNumIdle() {
return (pool == null) ? 0 : pool.getNumIdle();
}
// ----------------------------------------------------------------------
// Inherited abstract methods
protected PooledConnectionAndInfo
getPooledConnectionAndInfo(String username, String password)
throws SQLException {
synchronized(this) {
if (pool == null) {
try {
registerPool(username, password);
} catch (NamingException e) {
throw new SQLNestedException("RegisterPool failed", e);
}
}
}
PooledConnectionAndInfo info = null;
UserPassKey key = new UserPassKey(username, password);
try {
info = (PooledConnectionAndInfo) pool.borrowObject(key);
}
catch (Exception e) {
throw new SQLNestedException(
"Could not retrieve connection info from pool", e);
}
return info;
}
protected PooledConnectionManager getConnectionManager(UserPassKey upkey) {
return factory;
}
/**
* Returns a <code>SharedPoolDataSource {@link Reference}.
*
* @since 1.2.2
*/
public Reference getReference() throws NamingException {
Reference ref = new Reference(getClass().getName(),
SharedPoolDataSourceFactory.class.getName(), null);
ref.add(new StringRefAddr("instanceKey", instanceKey));
return ref;
}
private void registerPool(
String username, String password)
throws javax.naming.NamingException, SQLException {
ConnectionPoolDataSource cpds = testCPDS(username, password);
// Create an object pool to contain our PooledConnections
GenericKeyedObjectPool tmpPool = new GenericKeyedObjectPool(null);
tmpPool.setMaxActive(getMaxActive());
tmpPool.setMaxIdle(getMaxIdle());
tmpPool.setMaxWait(getMaxWait());
tmpPool.setWhenExhaustedAction(whenExhaustedAction(maxActive, maxWait));
tmpPool.setTestOnBorrow(getTestOnBorrow());
tmpPool.setTestOnReturn(getTestOnReturn());
tmpPool.setTimeBetweenEvictionRunsMillis(
getTimeBetweenEvictionRunsMillis());
tmpPool.setNumTestsPerEvictionRun(getNumTestsPerEvictionRun());
tmpPool.setMinEvictableIdleTimeMillis(getMinEvictableIdleTimeMillis());
tmpPool.setTestWhileIdle(getTestWhileIdle());
pool = tmpPool;
// Set up the factory we will use (passing the pool associates
// the factory with the pool, so we do not have to do so
// explicitly)
factory = new KeyedCPDSConnectionFactory(cpds, pool, getValidationQuery(),
isRollbackAfterValidation());
}
protected void setupDefaults(Connection con, String username) throws SQLException {
boolean defaultAutoCommit = isDefaultAutoCommit();
if (con.getAutoCommit() != defaultAutoCommit) {
con.setAutoCommit(defaultAutoCommit);
}
int defaultTransactionIsolation = getDefaultTransactionIsolation();
if (defaultTransactionIsolation != UNKNOWN_TRANSACTIONISOLATION) {
con.setTransactionIsolation(defaultTransactionIsolation);
}
boolean defaultReadOnly = isDefaultReadOnly();
if (con.isReadOnly() != defaultReadOnly) {
con.setReadOnly(defaultReadOnly);
}
}
/**
* Supports Serialization interface.
*
* @param in a <code>java.io.ObjectInputStream value
* @exception IOException if an error occurs
* @exception ClassNotFoundException if an error occurs
*/
private void readObject(ObjectInputStream in)
throws IOException, ClassNotFoundException {
try
{
in.defaultReadObject();
SharedPoolDataSource oldDS = (SharedPoolDataSource)
new SharedPoolDataSourceFactory()
.getObjectInstance(getReference(), null, null, null);
this.pool = oldDS.pool;
}
catch (NamingException e)
{
throw new IOException("NamingException: " + e);
}
}
}
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