/*
* The Apache Software License, Version 1.1
*
*
* Copyright (c) 1999 The Apache Software Foundation. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution,
* if any, must include the following acknowledgment:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowledgment may appear in the software itself,
* if and wherever such third-party acknowledgments normally appear.
*
* 4. The names "Xalan" and "Apache Software Foundation" must
* not be used to endorse or promote products derived from this
* software without prior written permission. For written
* permission, please contact apache@apache.org.
*
* 5. Products derived from this software may not be called "Apache",
* nor may "Apache" appear in their name, without prior written
* permission of the Apache Software Foundation.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation and was
* originally based on software copyright (c) 1999, Lotus
* Development Corporation., http://www.lotus.com. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*/
package org.apache.xalan.lib.sql;
import java.util.Properties;
import java.util.Vector;
import java.util.Enumeration;
import java.lang.String;
import java.sql.Connection;
import java.sql.SQLException;
import java.sql.DatabaseMetaData;
import java.sql.DriverManager;
public class DefaultConnectionPool implements ConnectionPool
{
private final static boolean DEBUG = false;
/**
* The basic information to make a JDBC Connection
*/
private String m_driver = new String("");
private String m_url = new String("");
/**
* The mimimum size of the connection pool, if the
* number of available connections falls below this
* mark, min connections will be allocated. The Connection
* Pool will always be somewhere between MinSize and MinSize*2
*
*/
private int m_PoolMinSize = 1;
/**
* Always implement the properties mechinism, if the Password
* or Username is set seperatly then we will add them to the
* property manually.
*
*/
private Properties m_ConnectionProtocol = new Properties();
/**
* Storage for the PooledConnections
*/
private Vector m_pool = new Vector();
/**
* Are we active ??
*/
private boolean m_IsActive = false;
public DefaultConnectionPool() {}
/**
* Are we active, if not then released connections will be
* closed on release and new connections will be refused.
*
* @param <code>boolean flag</code>, Set the active flag.
*/
public void disablePool()
{
m_IsActive = false;
freeUnused();
}
public void enablePool()
{
m_IsActive = true;
}
/**
* Return our current Active state
*/
public boolean isEnabled()
{
return m_IsActive;
}
/**
* Set the driver call to be used to create connections
*/
public void setDriver(String d)
{
m_driver = d;
}
/**
* Set the url used to connect to the database
*/
public void setURL(String url)
{
m_url = url;
}
/**
* Go through the connection pool and release any connections
* that are not InUse;
*
*/
public void freeUnused()
{
// Iterate over the entire pool closing the
// JDBC Connections.
for ( int x = 0; x < m_pool.size(); x++ )
{
PooledConnection pcon =
(PooledConnection) m_pool.elementAt(x);
// If the PooledConnection is not in use, close it
if ( pcon.inUse() == false )
{
if (DEBUG)
{
System.err.println("Closing JDBC Connection " + x);
}
pcon.close();
}
}
}
/**
* Is our ConnectionPool have any connections that are still in Use ??
*/
public boolean hasActiveConnections()
{
return (m_pool.size() > 0);
}
/**
* Set the password in the property set.
*/
public void setPassword(String p)
{
m_ConnectionProtocol.put("password", p);
}
/**
* Set the user name in the property set
*/
public void setUser(String u)
{
m_ConnectionProtocol.put("user", u);
}
/**
* Copy the properties from the source to our properties
*/
public void setProtocol(Properties p)
{
Enumeration e = p.keys();
while (e.hasMoreElements())
{
String key = (String) e.nextElement();
m_ConnectionProtocol.put(key, p.getProperty(key));
}
}
/**
* Override the current number of connections to keep in the pool. This
* setting will only have effect on a new pool or when a new connection
* is requested and there is less connections that this setting.
*/
public void setMinConnections(int n)
{
m_PoolMinSize = n;
}
/**
* Try to aquire a new connection, if it succeeds then return
* true, else return false.
* Note: This method will cause the connection pool to be built.
*
*/
public boolean testConnection()
{
try
{
if (DEBUG)
{
System.out.println("Testing Connection");
}
Connection conn = getConnection();
if (DEBUG)
{
DatabaseMetaData dma = conn.getMetaData();
System.out.println("\nConnected to " + dma.getURL());
System.out.println("Driver " + dma.getDriverName());
System.out.println("Version " + dma.getDriverVersion());
System.out.println("");
}
if (conn == null) return false;
releaseConnection(conn);
if (DEBUG)
{
System.out.println("Testing Connection, SUCCESS");
}
return true;
}
catch(Exception e)
{
if (DEBUG)
{
System.out.println("Testing Connection, FAILED");
e.printStackTrace();
}
return false;
}
}
// Find an available connection
public synchronized Connection getConnection()
throws IllegalArgumentException, SQLException
{
PooledConnection pcon = null;
// We will fill up the pool any time it is less than the
// Minimum. THis could be cause by the enableing and disabling
// or the pool.
//
if ( m_pool.size() < m_PoolMinSize ) { initializePool(); }
// find a connection not in use
for ( int x = 0; x < m_pool.size(); x++ )
{
pcon = (PooledConnection) m_pool.elementAt(x);
// Check to see if the Connection is in use
if ( pcon.inUse() == false )
{
// Mark it as in use
pcon.setInUse(true);
// return the JDBC Connection stored in the
// PooledConnection object
return pcon.getConnection();
}
}
// Could not find a free connection,
// create and add a new one
// Create a new JDBC Connection
Connection con = createConnection();
// Create a new PooledConnection, passing it the JDBC
// Connection
pcon = new PooledConnection(con);
// Mark the connection as in use
pcon.setInUse(true);
// Add the new PooledConnection object to the pool
m_pool.addElement(pcon);
// return the new Connection
return pcon.getConnection();
}
public synchronized void releaseConnection(Connection con)
throws SQLException
{
// find the PooledConnection Object
for ( int x = 0; x < m_pool.size(); x++ )
{
PooledConnection pcon =
(PooledConnection) m_pool.elementAt(x);
// Check for correct Connection
if ( pcon.getConnection() == con )
{
if (DEBUG)
{
System.out.println("Releasing Connection " + x);
}
if (! isEnabled())
{
con.close();
m_pool.removeElementAt(x);
if (DEBUG)
{
System.out.println("-->Inactive Pool, Closing connection");
}
}
else
{
// Set it's inuse attribute to false, which
// releases it for use
pcon.setInUse(false);
}
break;
}
}
}
private Connection createConnection()
throws SQLException
{
Connection con = null;
// Create a Connection
con = DriverManager.getConnection( m_url, m_ConnectionProtocol );
return con;
}
// Initialize the pool
public synchronized void initializePool()
throws IllegalArgumentException, SQLException
{
// Check our initial values
if ( m_driver == null )
{
throw new IllegalArgumentException("No Driver Name Specified!");
}
if ( m_url == null )
{
throw new IllegalArgumentException("No URL Specified!");
}
if ( m_PoolMinSize < 1 )
{
throw new IllegalArgumentException("Pool size is less than 1!");
}
// Create the Connections
// Load the Driver class file
try
{
Class.forName( m_driver );
}
catch(ClassNotFoundException e)
{
throw new IllegalArgumentException("Invalid Driver Name Specified!");
}
// IF we are not active, don't actuall build a pool yet
// Just set up the driver and periphal items.
if ( !m_IsActive) return;
// Create Connections based on the size member
do
{
Connection con = createConnection();
if ( con != null )
{
// Create a PooledConnection to encapsulate the
// real JDBC Connection
PooledConnection pcon = new PooledConnection(con);
// Add the Connection the pool.
addConnection(pcon);
if (DEBUG) System.out.println("Adding DB Connection to the Pool");
}
}
while (m_pool.size() < m_PoolMinSize);
}
// Adds the PooledConnection to the pool
private void addConnection(PooledConnection value)
{
// Add the PooledConnection Object to the vector
m_pool.addElement(value);
}
protected void finalize()
throws Throwable
{
if (DEBUG)
{
System.out.println("In Default Connection Pool, Finalize");
}
// Iterate over the entire pool closing the
// JDBC Connections.
for ( int x = 0; x < m_pool.size(); x++ )
{
if (DEBUG)
{
System.out.println("Closing JDBC Connection " + x);
}
PooledConnection pcon =
(PooledConnection) m_pool.elementAt(x);
// If the PooledConnection is not in use, close it
if ( pcon.inUse() == false ) { pcon.close(); }
else
{
if (DEBUG)
{
System.out.println("--> Force close");
}
// If it still in use, sleep for 30 seconds and
// force close.
try
{
java.lang.Thread.sleep(30000);
pcon.close();
}
catch (InterruptedException ie)
{
if (DEBUG) System.err.println(ie.getMessage());
}
}
}
if (DEBUG)
{
System.out.println("Exit Default Connection Pool, Finalize");
}
super.finalize();
}
}