org.springframework.jdbc.datasource
Class TransactionAwareDataSourceProxy

java.lang.Object
  org.springframework.jdbc.datasource.DelegatingDataSource
      org.springframework.jdbc.datasource.TransactionAwareDataSourceProxy

All Implemented Interfaces:

DataSource, InitializingBean

public class TransactionAwareDataSourceProxy
extends DelegatingDataSource

Proxy for a target DataSource, adding awareness of Spring-managed transactions. Similar to a transactional JNDI DataSource as provided by a J2EE server.

Data access code that should remain unaware of Spring's data access support can work with this proxy to seamlessly participate in Spring-managed transactions. Note that the transaction manager, for example DataSourceTransactionManager, still needs to work with the underlying DataSource, not with this proxy.

Make sure that TransactionAwareDataSourceProxy is the outermost DataSource of a chain of DataSource proxies/adapters. TransactionAwareDataSourceProxy can delegate either directly to the target connection pool or to some intermediate proxy/adapter like LazyConnectionDataSourceProxy or UserCredentialsDataSourceAdapter.

Delegates to DataSourceUtils for automatically participating in thread-bound transactions, for example managed by DataSourceTransactionManager. getConnection calls and close calls on returned Connections will behave properly within a transaction, that is, always work on the transactional Connection. If not within a transaction, normal DataSource behavior applies.

This proxy allows data access code to work with the plain JDBC API and still participate in Spring-managed transactions, similar to JDBC code in a J2EE/JTA environment. However, if possible, use Spring's DataSourceUtils, JdbcTemplate or JDBC operation objects to get transaction participation even without a proxy for the target DataSource, avoiding the need to define such a proxy in the first place.

As a further effect, using a transaction-aware DataSource will apply remaining transaction timeouts to all created JDBC (Prepared/Callable)Statement. This means that all operations performed through standard JDBC will automatically participate in Spring-managed transaction timeouts.

NOTE: This DataSource proxy needs to return wrapped Connections to handle close calls on them properly. Therefore, the returned Connections cannot be cast to a native JDBC Connection type like OracleConnection, or to a connection pool implementation type. Use a corresponding NativeJdbcExtractor to retrieve the native JDBC Connection.

Since:

1.1

Author:

Juergen Hoeller

See Also:

DataSource.getConnection(), Connection.close(), DataSourceUtils.doGetConnection(javax.sql.DataSource), DataSourceUtils.doReleaseConnection(java.sql.Connection, javax.sql.DataSource), DataSourceUtils.applyTransactionTimeout(java.sql.Statement, javax.sql.DataSource), ConnectionProxy, NativeJdbcExtractor

Constructor Summary

TransactionAwareDataSourceProxy()
Create a new TransactionAwareDataSourceProxy.

TransactionAwareDataSourceProxy(DataSource targetDataSource)
Create a new TransactionAwareDataSourceProxy.

Method Summary

Connection	getConnection() Delegate to DataSourceUtils for automatically participating in Spring-managed transactions.
protected Connection	getTransactionAwareConnectionProxy(Connection target, DataSource dataSource) Wrap the given Connection with a proxy that delegates every method call to it but delegates close calls to DataSourceUtils.

Methods inherited from class org.springframework.jdbc.datasource.DelegatingDataSource

afterPropertiesSet, getConnection, getLoginTimeout, getLogWriter, getTargetDataSource, setLoginTimeout, setLogWriter, setTargetDataSource

Methods inherited from class java.lang.Object

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

Constructor Detail

TransactionAwareDataSourceProxy

public TransactionAwareDataSourceProxy()

Create a new TransactionAwareDataSourceProxy.

See Also:

DelegatingDataSource.setTargetDataSource(javax.sql.DataSource)

TransactionAwareDataSourceProxy

public TransactionAwareDataSourceProxy(DataSource targetDataSource)

Create a new TransactionAwareDataSourceProxy.

Parameters:

targetDataSource - the target DataSource

Method Detail

getConnection

public Connection getConnection()
                         throws SQLException

Delegate to DataSourceUtils for automatically participating in Spring-managed transactions. Throws the original SQLException, if any.

The returned Connection handle implements the ConnectionProxy interface, allowing to retrieve the underlying target Connection.

Specified by:

getConnection in interface DataSource

Overrides:

getConnection in class DelegatingDataSource

Returns:

a transactional Connection if any, a new one else

Throws:

SQLException

See Also:

DataSourceUtils.doGetConnection(javax.sql.DataSource), ConnectionProxy.getTargetConnection()

getTransactionAwareConnectionProxy

protected Connection getTransactionAwareConnectionProxy(Connection target,
                                                        DataSource dataSource)

Wrap the given Connection with a proxy that delegates every method call to it but delegates close calls to DataSourceUtils.

Parameters:

target - the original Connection to wrap

dataSource - DataSource that the Connection came from

Returns:

the wrapped Connection

See Also:

Connection.close(), DataSourceUtils.doReleaseConnection(java.sql.Connection, javax.sql.DataSource)