org.apache.struts.util
Class GenericDataSource

java.lang.Object
  |
  +--org.apache.struts.util.GenericDataSource

All Implemented Interfaces:

javax.sql.DataSource

public class GenericDataSource

extends java.lang.Object

implements javax.sql.DataSource

Generic data source implementation of the DataSource interface. WARNING - This implementation does not know how to provide connections with different username/password combinations. Calling this version of the implementation using the getConnection(username,password) signature will throw an exception.

The following properties are supported by the standard GenericDataSource implementation:

Property	Description
autoCommit	Set to true if you want the connections returned to you by calling getConnection() to be configured in "auto-commit after every statement" mode. The default value is true, to conform to JDBC standard conventions.
description	A short textual description of this data source. This property is required by the javax.sql.DataSource interface, but is not used within this implementation.
driverClass	The fully qualified class name of the JDBC driver to be utilized for the connections created by this data source. Consult the documentation for your JDBC driver to identify the value to be configured for this property.
maxCount	The maximum number of JDBC connections that will be created by this data source. This value must be greater than or equal to the value specified for the minCount property.
minCount	The minimum number of JDBC connections to establish when this data source is first opened. This value must be less than or equal to the value specified for the maxCount property.
password	The database password used to establish the connections created by this connection pool, in conjunction with the username specified in the user property.
pingCommand	A non-query SQL command that, if specified, will be executed before a connection is returned by a call to getConnection(). If any SQLException is thrown by the execution of this statement, it is assumed that this connection is stale and it will be discarded. Because this happens on every connection allocation, you should ensure that the statement executes very quickly.
pingQuery	A query SQL command (i.e. a SELECT) that, if specified, will be executed before a connection is returned by a call to getConnection(). If any SQLException is thrown by the execution of this query (or by the subsequent processing of the entire returned ResultSet), it is assumed that this connection is stale and it will be discarded. Because this happens on every connection allocation, you should ensure that the statement executes very quickly.
readOnly	Set to true if you want the connections returned to you by calling getConnection() to be configured for read only operations. This can result in more efficient database access, because the database will know it does not need to retain undo logs for rolling back the transaction. The default value is false.
url	The connection URL to be passed to our JDBC driver when establishing a new connection. The value specified typically starts with jdbc:, and includes a reference to the host (and, optionally, the port number) at which the database server is listening for connections, plus the name of the database to be opened. Consult the documentation for your JDBC driver to identify the value to be configured for this property.
user	The database username used to establish the connections created by this connection pool, in conjunction with the password specified in the password property.

In addition, you can add to the set of Properties passed to the JDBC driver by calling addProperty().

Version:

$Revision: 1.1 $ $Date: 2001/09/17 20:13:29 $

Author:

Craig R. McClanahan, Ted Husted

Field Summary

protected int	activeCount The number of connections that have been created by this data source.
protected boolean	autoCommit The default auto-commit state for newly created connections.
protected boolean	closed Has this data source been closed?
protected java.util.LinkedList	connections The list of Connections (wrapped in our associated wrapper class) that have been created but are not currently in use.
protected int	debug The debugging detail level for this data source.
protected java.lang.String	description The description of this data source.
protected java.sql.Driver	driver The JDBC driver that we use as a connection factory.
protected java.lang.String	driverClass The Java class name of the JDBC driver to use.
protected int	loginTimeout The login timeout for this data source.
protected java.io.PrintWriter	logWriter The log writer for this data source.
protected int	maxCount The maximum number of connections to be created.
protected int	minCount The minimum number of connections to be created.
protected java.lang.String	password The database password for use in establishing a connection.
protected java.lang.String	pingCommand The non-query SQL command used to ping an allocated connection.
protected java.lang.String	pingQuery The query SQL command used to ping an allocated connection.
protected java.util.Properties	properties The connection properties for use in establishing connections.
protected boolean	readOnly The default read-only state for newly created connections.
private static java.lang.String	SQLEXCEPTION_GETCONNECTION
protected java.lang.String	url The JDBC URL for the database connection to be opened.
protected int	useCount The number of connections created by this data source that are currently in use.
protected java.lang.String	user The database username for use in establishing a connection.

Constructor Summary

GenericDataSource()

Method Summary

void	addProperty(java.lang.String name, java.lang.String value) Add a generic property to the list of connection properties to be used.
void	close() Close all connections that have been created by this data source.
protected java.sql.Connection	createConnection() Create, configure, and return a new JDBC Connection that has been wrapped in our corresponding wrapper.
int	getActiveCount()
boolean	getAutoCommit()
java.sql.Connection	getConnection() Attempt to establish a database connection.
java.sql.Connection	getConnection(java.lang.String username, java.lang.String password) Attempt to establish a database connection.
int	getDebug()
java.lang.String	getDescription()
java.lang.String	getDriverClass()
int	getLoginTimeout() Return the login timeout for this data source.
java.io.PrintWriter	getLogWriter() Return the log writer for this data source.
int	getMaxCount()
int	getMinCount()
java.lang.String	getPassword()
java.lang.String	getPingCommand()
java.lang.String	getPingQuery()
boolean	getReadOnly()
java.lang.String	getUrl()
int	getUseCount()
java.lang.String	getUser()
protected void	log(java.lang.String message) Log the specified message to our log writer, if we have one.
protected void	log(java.lang.String message, java.lang.Throwable throwable) Log the specified message and exception to our log writer, if we have one.
void	open() Open the initial connections that are appropriate for this data source.
protected void	ping(java.sql.Connection conn) Perform any configured pingCommand and/or pingQuery on the specified connection, returning any SQLException that is encountered along the way.
(package private) void	returnConnection(GenericConnection conn) Return this connection to the available connection pool.
void	setAutoCommit(boolean autoCommit)
void	setDebug(int debug)
void	setDescription(java.lang.String description)
void	setDriverClass(java.lang.String driverClass)
void	setLoginTimeout(int loginTimeout) Set the login timeout for this data source.
void	setLogWriter(java.io.PrintWriter logWriter) Set the log writer for this data source.
void	setMaxCount(int maxCount)
void	setMinCount(int minCount)
void	setPassword(java.lang.String password)
void	setPingCommand(java.lang.String pingCommand)
void	setPingQuery(java.lang.String pingQuery)
void	setReadOnly(boolean readOnly)
void	setUrl(java.lang.String url)
void	setUser(java.lang.String user)
java.lang.String	toString() Return a string representation of this component.

Methods inherited from class java.lang.Object

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

Field Detail

SQLEXCEPTION_GETCONNECTION

private static final java.lang.String SQLEXCEPTION_GETCONNECTION

closed

protected boolean closed

Has this data source been closed?

connections

protected java.util.LinkedList connections

The list of Connections (wrapped in our associated wrapper class) that have been created but are not currently in use.

driver

protected java.sql.Driver driver

The JDBC driver that we use as a connection factory.

loginTimeout

protected int loginTimeout

The login timeout for this data source.

logWriter

protected java.io.PrintWriter logWriter

The log writer for this data source.

activeCount

protected int activeCount

The number of connections that have been created by this data source.

autoCommit

protected boolean autoCommit

The default auto-commit state for newly created connections.

debug

protected int debug

The debugging detail level for this data source.

description

protected java.lang.String description

The description of this data source.

driverClass

protected java.lang.String driverClass

The Java class name of the JDBC driver to use.

maxCount

protected int maxCount

The maximum number of connections to be created.

minCount

protected int minCount

The minimum number of connections to be created.

password

protected java.lang.String password

The database password for use in establishing a connection.

pingCommand

protected java.lang.String pingCommand

The non-query SQL command used to ping an allocated connection.

pingQuery

protected java.lang.String pingQuery

The query SQL command used to ping an allocated connection.

properties

protected java.util.Properties properties

The connection properties for use in establishing connections.

readOnly

protected boolean readOnly

The default read-only state for newly created connections.

url

protected java.lang.String url

The JDBC URL for the database connection to be opened.

useCount

protected int useCount

The number of connections created by this data source that are currently in use.

user

protected java.lang.String user

The database username for use in establishing a connection.

Constructor Detail

GenericDataSource

public GenericDataSource()

Method Detail

addProperty

public void addProperty(java.lang.String name,
                        java.lang.String value)

Add a generic property to the list of connection properties to be used.

Parameters:

name - Name of the generic property

value - Corresponding generic property value

getActiveCount

public int getActiveCount()

getAutoCommit

public boolean getAutoCommit()

setAutoCommit

public void setAutoCommit(boolean autoCommit)

getDebug

public int getDebug()

setDebug

public void setDebug(int debug)

getDescription

public java.lang.String getDescription()

setDescription

public void setDescription(java.lang.String description)

getDriverClass

public java.lang.String getDriverClass()

setDriverClass

public void setDriverClass(java.lang.String driverClass)

getMaxCount

public int getMaxCount()

setMaxCount

public void setMaxCount(int maxCount)

getMinCount

public int getMinCount()

setMinCount

public void setMinCount(int minCount)

getPassword

public java.lang.String getPassword()

setPassword

public void setPassword(java.lang.String password)

getPingCommand

public java.lang.String getPingCommand()

setPingCommand

public void setPingCommand(java.lang.String pingCommand)

getPingQuery

public java.lang.String getPingQuery()

setPingQuery

public void setPingQuery(java.lang.String pingQuery)

getReadOnly

public boolean getReadOnly()

setReadOnly

public void setReadOnly(boolean readOnly)

getUrl

public java.lang.String getUrl()

setUrl

public void setUrl(java.lang.String url)

getUseCount

public int getUseCount()

getUser

public java.lang.String getUser()

setUser

public void setUser(java.lang.String user)

getConnection

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

Attempt to establish a database connection.

Specified by:

getConnection in interface javax.sql.DataSource

Throws:

java.sql.SQLException - if a database access error occurs

getConnection

public java.sql.Connection getConnection(java.lang.String username,
                                         java.lang.String password)
                                  throws java.sql.SQLException

Attempt to establish a database connection. WARNING - The specified username and password are not supported by this implementation.

Specified by:

getConnection in interface javax.sql.DataSource

Parameters:

username - Database username for this connection

password - Database password for this connection

Throws:

java.sql.SQLException - if a database access error occurs

getLoginTimeout

public int getLoginTimeout()
                    throws java.sql.SQLException

Return the login timeout for this data source.

Specified by:

getLoginTimeout in interface javax.sql.DataSource

Throws:

java.sql.SQLException - if a database access error occurs

getLogWriter

public java.io.PrintWriter getLogWriter()
                                 throws java.sql.SQLException

Return the log writer for this data source.

Specified by:

getLogWriter in interface javax.sql.DataSource

Throws:

java.sql.SQLException - if a database access error occurs

setLoginTimeout

public void setLoginTimeout(int loginTimeout)
                     throws java.sql.SQLException

Set the login timeout for this data source.

Specified by:

setLoginTimeout in interface javax.sql.DataSource

Parameters:

loginTimeout - The new login timeout

Throws:

java.sql.SQLException - if a database access error occurs

setLogWriter

public void setLogWriter(java.io.PrintWriter logWriter)
                  throws java.sql.SQLException

Set the log writer for this data source.

Specified by:

setLogWriter in interface javax.sql.DataSource

Parameters:

logWriter - The new log writer

Throws:

java.sql.SQLException - if a database access error occurs

close

public void close()
           throws java.sql.SQLException

Close all connections that have been created by this data source.

Throws:

java.sql.SQLException - if a database access error occurs

open

public void open()
          throws java.sql.SQLException

Open the initial connections that are appropriate for this data source.

Throws:

java.sql.SQLException - if a database access error occurs

toString

public java.lang.String toString()

Return a string representation of this component.

Overrides:

toString in class java.lang.Object

createConnection

protected java.sql.Connection createConnection()
                                        throws java.sql.SQLException

Create, configure, and return a new JDBC Connection that has been wrapped in our corresponding wrapper.

Throws:

java.sql.SQLException - if a database access error occurs

log

protected void log(java.lang.String message)

Log the specified message to our log writer, if we have one.

Parameters:

message - The message to be logged

log

protected void log(java.lang.String message,
                   java.lang.Throwable throwable)

Log the specified message and exception to our log writer, if we have one.

Parameters:

message - The message to be logged

throwable - The exception to be logged

ping

protected void ping(java.sql.Connection conn)
             throws java.sql.SQLException

Perform any configured pingCommand and/or pingQuery on the specified connection, returning any SQLException that is encountered along the way.

Parameters:

conn - The connection to be pinged

returnConnection

void returnConnection(GenericConnection conn)

Return this connection to the available connection pool.

Parameters:

conn - The connection being returned