org.springframework.jdbc.support.nativejdbc
Interface NativeJdbcExtractor

All Known Implementing Classes:

CommonsDbcpNativeJdbcExtractor, JBossNativeJdbcExtractor, SimpleNativeJdbcExtractor, XAPoolNativeJdbcExtractor

public interface NativeJdbcExtractor

Interface for extracting native JDBC objects from wrapped objects coming from connection pools. This is necessary to be able to case to native implementations like OracleConnection or OracleResultSet in application code, for example to create Blobs or access other vendor-specific features.

Note: Setting a custom NativeJdbcExtractor is just necessary if you want to cast to database-specific implementations, like OracleConnection/OracleResultSet. Else, any wrapped JDBC object will be fine.

Note: To be able to support any pool's strategy of native ResultSet wrapping, it is advisable to get both the native Statement and the native ResultSet via this extractor. Some pools just allow to unwrap the Statement, some just to unwrap the ResultSet - the above strategy will cover both. It is typically not necessary to unwrap the Connection to retrieve a native ResultSet.

When working with a simple connection pool that wraps Connections but not Statements, a SimpleNativeJdbcExtractor is often sufficient. However, some pools (like Jakarta's Commons DBCP) wrap all JDBC objects that they return: Therefore, you need to use a specific NativeJdbcExtractor (like CommonsDbcpNativeJdbcExtractor) with them.

JdbcTemplate can properly apply a NativeJdbcExtractor if specified, correctly unwrapping all JDBC objects that it creates. Note that this is just necessary if you want to cast to native implementations in your data access code.

The Oracle-specific implementation of Spring's LobHandler interface needs a NativeJdbcExtractor to be able to work on the native OracleConnection. This is also necessary for other Oracle-specific features that you may want to leverage in your applications, like InterMedia.

Since:

25.08.2003

Author:

Juergen Hoeller

See Also:

SimpleNativeJdbcExtractor, CommonsDbcpNativeJdbcExtractor, JdbcTemplate.setNativeJdbcExtractor(org.springframework.jdbc.support.nativejdbc.NativeJdbcExtractor), OracleLobHandler.setNativeJdbcExtractor(org.springframework.jdbc.support.nativejdbc.NativeJdbcExtractor)

Method Summary

java.sql.CallableStatement	getNativeCallableStatement(java.sql.CallableStatement cs) Retrieve the underlying native JDBC CallableStatement for the given statement.
java.sql.Connection	getNativeConnection(java.sql.Connection con) Retrieve the underlying native JDBC Connection for the given Connection.
java.sql.Connection	getNativeConnectionFromStatement(java.sql.Statement stmt) Retrieve the underlying native JDBC Connection for the given Statement.
java.sql.PreparedStatement	getNativePreparedStatement(java.sql.PreparedStatement ps) Retrieve the underlying native JDBC PreparedStatement for the given statement.
java.sql.ResultSet	getNativeResultSet(java.sql.ResultSet rs) Retrieve the underlying native JDBC ResultSet for the given statement.
java.sql.Statement	getNativeStatement(java.sql.Statement stmt) Retrieve the underlying native JDBC Statement for the given Statement.
boolean	isNativeConnectionNecessaryForNativeCallableStatements() Return whether it is necessary to work on the native Connection to receive native CallableStatements.
boolean	isNativeConnectionNecessaryForNativePreparedStatements() Return whether it is necessary to work on the native Connection to receive native PreparedStatements.
boolean	isNativeConnectionNecessaryForNativeStatements() Return whether it is necessary to work on the native Connection to receive native Statements.

Method Detail

isNativeConnectionNecessaryForNativeStatements

public boolean isNativeConnectionNecessaryForNativeStatements()

Return whether it is necessary to work on the native Connection to receive native Statements.

This should be true if the connection pool does not allow to extract the native JDBC objects from its Statement wrapper but supports a way to retrieve the native JDBC Connection. This way, applications can still receive native Statements and ResultSet via working on the native JDBC Connection.

isNativeConnectionNecessaryForNativePreparedStatements

public boolean isNativeConnectionNecessaryForNativePreparedStatements()

Return whether it is necessary to work on the native Connection to receive native PreparedStatements.

This should be true if the connection pool does not allow to extract the native JDBC objects from its PreparedStatement wrappers but supports a way to retrieve the native JDBC Connection. This way, applications can still receive native Statements and ResultSet via working on the native JDBC Connection.

isNativeConnectionNecessaryForNativeCallableStatements

public boolean isNativeConnectionNecessaryForNativeCallableStatements()

Return whether it is necessary to work on the native Connection to receive native CallableStatements.

This should be true if the connection pool does not allow to extract the native JDBC objects from its CallableStatement wrappers but supports a way to retrieve the native JDBC Connection. This way, applications can still receive native Statements and ResultSet via working on the native JDBC Connection.

getNativeConnection

public java.sql.Connection getNativeConnection(java.sql.Connection con)
                                        throws java.sql.SQLException

Retrieve the underlying native JDBC Connection for the given Connection. Supposed to return the given Connection if not capable of unwrapping.

Parameters:

con - the Connection handle, potentially wrapped by a connection pool

Returns:

the underlying native JDBC Connection, if possible; else, the original Connection

Throws:

java.sql.SQLException - if thrown by JDBC methods

getNativeConnectionFromStatement

public java.sql.Connection getNativeConnectionFromStatement(java.sql.Statement stmt)
                                                     throws java.sql.SQLException

Retrieve the underlying native JDBC Connection for the given Statement. Supposed to return the Statement.getConnection if not capable of unwrapping.

Having this extra method allows for more efficient unwrapping if data access code already has a Statement. Statement.getConnection() often returns the native JDBC Connection even if the Statement itself is wrapped by a pool.

Parameters:

stmt - the Statement handle, potentially wrapped by a connection pool

Returns:

the underlying native JDBC Connection, if possible; else, the original Connection

Throws:

java.sql.SQLException - if thrown by JDBC methods

getNativeStatement

public java.sql.Statement getNativeStatement(java.sql.Statement stmt)
                                      throws java.sql.SQLException

Retrieve the underlying native JDBC Statement for the given Statement. Supposed to return the given Statement if not capable of unwrapping.

Parameters:

stmt - the Statement handle, potentially wrapped by a connection pool

Returns:

the underlying native JDBC Statement, if possible; else, the original Connection

Throws:

java.sql.SQLException - if thrown by JDBC methods

getNativePreparedStatement

public java.sql.PreparedStatement getNativePreparedStatement(java.sql.PreparedStatement ps)
                                                      throws java.sql.SQLException

Retrieve the underlying native JDBC PreparedStatement for the given statement. Supposed to return the given PreparedStatement if not capable of unwrapping.

Parameters:

ps - the PreparedStatement handle, potentially wrapped by a connection pool

Returns:

the underlying native JDBC PreparedStatement, if possible; else, the original Connection

Throws:

java.sql.SQLException - if thrown by JDBC methods

getNativeCallableStatement

public java.sql.CallableStatement getNativeCallableStatement(java.sql.CallableStatement cs)
                                                      throws java.sql.SQLException

Retrieve the underlying native JDBC CallableStatement for the given statement. Supposed to return the given CallableStatement if not capable of unwrapping.

Parameters:

cs - the CallableStatement handle, potentially wrapped by a connection pool

Returns:

the underlying native JDBC CallableStatement, if possible; else, the original Connection

Throws:

java.sql.SQLException - if thrown by JDBC methods

getNativeResultSet

public java.sql.ResultSet getNativeResultSet(java.sql.ResultSet rs)
                                      throws java.sql.SQLException

Retrieve the underlying native JDBC ResultSet for the given statement. Supposed to return the given ResultSet if not capable of unwrapping.

Parameters:

rs - the ResultSet handle, potentially wrapped by a connection pool

Returns:

the underlying native JDBC ResultSet, if possible; else, the original Connection

Throws:

java.sql.SQLException - if thrown by JDBC methods