info.aduna.gee.publication.servlets.jdbc
Class ConnectionPool

java.lang.Object
  info.aduna.gee.publication.servlets.jdbc.ConnectionPool

public class ConnectionPool
extends Object

Class ConnectionPool manages a pool of connections to the database for a certain (virtual) host. Clients can try to get a connection, optionally wait until one becomes available, get the connection, do something with it and return the connection to the pool. Note that the ConnectionPool decides whether or not to reuse connections. The current implementation does not reuse connections.

Field Summary

protected String	_dbURL
protected int	_freeConnections Available number of connections
protected int	_numberOfConnections Maximum number of connections
protected ArrayList	_requestQueue Clients that should be notified when a connection becomes available.
static Object	ABORT
static Object	WAIT

Constructor Summary

ConnectionPool(String host, boolean useInProcessDatabase)
Construct a new ConnectionPool for the specified host.

Method Summary

protected Connection	_getNewConnection(String name, String password)
Object	getConnection(Object client) Get a connection for the specified client.
void	returnConnection(Connection connection) Return a connection to the pool of free connections; if there is a waiting client, notify it.
int	size()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

WAIT

public static final Object WAIT

ABORT

public static final Object ABORT

_dbURL

protected String _dbURL

_numberOfConnections

protected int _numberOfConnections

Maximum number of connections

_freeConnections

protected int _freeConnections

Available number of connections

_requestQueue

protected ArrayList _requestQueue

Clients that should be notified when a connection becomes available.

Constructor Detail

ConnectionPool

public ConnectionPool(String host,
                      boolean useInProcessDatabase)

Construct a new ConnectionPool for the specified host.

Parameters:

host - The name of the host.

Method Detail

size

public int size()

Returns:

the total amount of connections managed by this pool.

getConnection

public Object getConnection(Object client)

Get a connection for the specified client. The client should take care to return the connection upon completion.

Returns:

either a Connection, WAIT or ABORT

See Also:

returnConnection(java.sql.Connection)

returnConnection

public void returnConnection(Connection connection)

Return a connection to the pool of free connections; if there is a waiting client, notify it.

Parameters:

connection - The connection to return to the pool.

_getNewConnection

protected Connection _getNewConnection(String name,
                                       String password)

Returns:

a new connection to the database, or null if there was some problem connecting to the database