org.apache.xalan.lib.sql
Class JNDIConnectionPool

java.lang.Object
  org.apache.xalan.lib.sql.JNDIConnectionPool

All Implemented Interfaces:

ConnectionPool

public class JNDIConnectionPool
extends java.lang.Object
implements ConnectionPool

A Connection Pool that wraps a JDBC datasource to provide connections. An instance of this class is created by XConnection when it attempts to resolves a ConnectionPool name as a JNDI data source. Most methods in this implementation do nothing since configuration is handled by the underlying JDBC datasource. Users should always call XConnection.close() from their stylsheet to explicitely close their connection. However, since there is no way to enforce this (Yikes!), it is recommended that a relatively short datasource timeout be used to prevent dangling connections.

Field Summary

private java.lang.reflect.Method	getConnection
private java.lang.reflect.Method	getConnectionWithArgs To maintain Java 1.3 compatibility, we need to work with the DataSource class through Reflection.
protected java.lang.Object	jdbcSource Reference to the datasource
protected java.lang.String	jndiPath The unique jndi path for this datasource.
protected java.lang.String	pwd Password for protected datasources.
protected java.lang.String	user User name for protected datasources.

Constructor Summary

JNDIConnectionPool()
Use of the default constructor requires the jndi path to be set via setJndiPath().

JNDIConnectionPool(java.lang.String jndiDatasourcePath)
Creates a connection pool with a specified JNDI path.

Method Summary

protected void	findDatasource() Internal method used to look up the datasource.
void	freeUnused() Intended to release unused connections from the pool.
java.sql.Connection	getConnection() Returns a connection from the JDNI DataSource found at the JNDI Datasource path.
java.lang.String	getJndiPath() Returns the path for the jndi datasource
boolean	hasActiveConnections() Always returns false, indicating that this wrapper has no idea of what connections the underlying JNDI source is maintaining.
boolean	isEnabled() Always returns true.
void	releaseConnection(java.sql.Connection con) Return a connection to the pool, the connection may be closed if the pool is inactive or has exceeded the max number of free connections
void	releaseConnectionOnError(java.sql.Connection con) Provide a mechinism to return a connection to the pool on Error.
void	setDriver(java.lang.String d) Not implemented and will throw an Error if called.
void	setJndiPath(java.lang.String jndiPath) Sets the path for the jndi datasource
void	setMinConnections(int n) Ignored in this implementation b/c the pooling is determined by the jndi dataosource.
void	setPassword(java.lang.String p) Sets the password for the connection.
void	setPoolEnabled(boolean flag) Releases the reference to the jndi datasource.
void	setProtocol(java.util.Properties p) Ignored in this implementation b/c the pooling is determined by the jndi dataosource.
void	setURL(java.lang.String url) Not implemented and will throw an Error if called.
void	setUser(java.lang.String u) Sets the user name for the connection.
boolean	testConnection() A simple test to see if the jndi datasource exists.

Methods inherited from class java.lang.Object

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

Field Detail

jdbcSource

protected java.lang.Object jdbcSource

Reference to the datasource

getConnectionWithArgs

private java.lang.reflect.Method getConnectionWithArgs

To maintain Java 1.3 compatibility, we need to work with the DataSource class through Reflection. The getConnection method is one of the methods used, and there are two different flavors.

getConnection

private java.lang.reflect.Method getConnection

jndiPath

protected java.lang.String jndiPath

The unique jndi path for this datasource.

user

protected java.lang.String user

User name for protected datasources.

pwd

protected java.lang.String pwd

Password for protected datasources.

Constructor Detail

JNDIConnectionPool

public JNDIConnectionPool()

Use of the default constructor requires the jndi path to be set via setJndiPath().

JNDIConnectionPool

public JNDIConnectionPool(java.lang.String jndiDatasourcePath)

Creates a connection pool with a specified JNDI path.

Parameters:

jndiDatasourcePath - Complete path to the JNDI datasource

Method Detail

setJndiPath

public void setJndiPath(java.lang.String jndiPath)

Sets the path for the jndi datasource

Parameters:

jndiPath -

getJndiPath

public java.lang.String getJndiPath()

Returns the path for the jndi datasource

Parameters:

jndiPath -

isEnabled

public boolean isEnabled()

Always returns true. This method was intended to indicate if the pool was enabled, however, in this implementation that is not relavant.

Specified by:

isEnabled in interface ConnectionPool

Returns:

setDriver

public void setDriver(java.lang.String d)

Not implemented and will throw an Error if called. Connection configuration is handled by the underlying JNDI DataSource.

Specified by:

setDriver in interface ConnectionPool

Parameters:

d -

setURL

public void setURL(java.lang.String url)

Not implemented and will throw an Error if called. Connection configuration is handled by the underlying JNDI DataSource.

Specified by:

setURL in interface ConnectionPool

Parameters:

d -

freeUnused

public void freeUnused()

Intended to release unused connections from the pool. Does nothing in this implementation.

Specified by:

freeUnused in interface ConnectionPool

hasActiveConnections

public boolean hasActiveConnections()

Always returns false, indicating that this wrapper has no idea of what connections the underlying JNDI source is maintaining.

Specified by:

hasActiveConnections in interface ConnectionPool

Returns:

setPassword

public void setPassword(java.lang.String p)

Sets the password for the connection. If the jndi datasource does not require a password (which is typical), this can be left null.

Specified by:

setPassword in interface ConnectionPool

Parameters:

p - the password

setUser

public void setUser(java.lang.String u)

Sets the user name for the connection. If the jndi datasource does not require a user name (which is typical), this can be left null.

Specified by:

setUser in interface ConnectionPool

Parameters:

u - the user name

getConnection

public java.sql.Connection getConnection()
                                  throws java.sql.SQLException

Returns a connection from the JDNI DataSource found at the JNDI Datasource path.

Specified by:

getConnection in interface ConnectionPool

Returns:

Throws:

java.sql.SQLException

findDatasource

protected void findDatasource()
                       throws javax.naming.NamingException

Internal method used to look up the datasource.

Throws:

javax.naming.NamingException

releaseConnection

public void releaseConnection(java.sql.Connection con)
                       throws java.sql.SQLException

Description copied from interface: ConnectionPool

Return a connection to the pool, the connection may be closed if the pool is inactive or has exceeded the max number of free connections

Specified by:

releaseConnection in interface ConnectionPool

Throws:

java.sql.SQLException

releaseConnectionOnError

public void releaseConnectionOnError(java.sql.Connection con)
                              throws java.sql.SQLException

Description copied from interface: ConnectionPool

Provide a mechinism to return a connection to the pool on Error. A good default behaviour is to close this connection and build a new one to replace it. Some JDBC impl's won't allow you to reuse a connection after an error occurs.

Specified by:

releaseConnectionOnError in interface ConnectionPool

Throws:

java.sql.SQLException

setPoolEnabled

public void setPoolEnabled(boolean flag)

Releases the reference to the jndi datasource. The original intention of this method was to actually turn the pool *off*. Since we are not managing the pool, we simply release our reference to the datasource. Future calls to the getConnection will simply recreate the datasource.

Specified by:

setPoolEnabled in interface ConnectionPool

Parameters:

flag - If false, the reference to the datasource is released.

setProtocol

public void setProtocol(java.util.Properties p)

Ignored in this implementation b/c the pooling is determined by the jndi dataosource.

Specified by:

setProtocol in interface ConnectionPool

Parameters:

p -

setMinConnections

public void setMinConnections(int n)

Ignored in this implementation b/c the pooling is determined by the jndi dataosource.

Specified by:

setMinConnections in interface ConnectionPool

Parameters:

n -

testConnection

public boolean testConnection()

A simple test to see if the jndi datasource exists. Note that this test does not ensure that the datasource will return valid connections.

Specified by:

testConnection in interface ConnectionPool