org.springframework.jdbc.support.lob
Class OracleLobHandler

java.lang.Object
  extended by org.springframework.jdbc.support.lob.AbstractLobHandler
      extended by org.springframework.jdbc.support.lob.OracleLobHandler
All Implemented Interfaces:
LobHandler

public class OracleLobHandler
extends AbstractLobHandler

LobHandler implementation for Oracle databases. Uses proprietary API to create oracle.sql.BLOB and oracle.sql.CLOB instances, as necessary when working with Oracle's JDBC driver. Note that this LobHandler requires Oracle JDBC driver 9i or higher!

While most databases are able to work with DefaultLobHandler, Oracle just accepts Blob/Clob instances created via its own proprietary BLOB/CLOB API, and additionally doesn't accept large streams for PreparedStatement's corresponding setter methods. Therefore, you need to use a strategy like this LobHandler implementation.

Needs to work on a native JDBC Connection, to be able to cast it to oracle.jdbc.OracleConnection. If you pass in Connections from a connection pool (the usual case in a J2EE environment), you need to set an appropriate NativeJdbcExtractor to allow for automatical retrieval of the underlying native JDBC Connection. LobHandler and NativeJdbcExtractor are separate concerns, therefore they are represented by separate strategy interfaces.

Coded via reflection to avoid dependencies on Oracle classes. Even reads in Oracle constants via reflection because of different Oracle drivers (classes12, ojdbc14) having different constant values! As this LobHandler initializes Oracle classes on instantiation, do not define this as eager-initializing singleton if you do not want to depend on the Oracle JAR being in the class path: use "lazy-init=true" to avoid this issue.

Since:
04.12.2003
Author:
Juergen Hoeller
See Also:
setNativeJdbcExtractor(org.springframework.jdbc.support.nativejdbc.NativeJdbcExtractor), oracle.sql.BLOB, oracle.sql.CLOB

Nested Class Summary
protected static interface OracleLobHandler.LobCallback
          Internal callback interface for use with createLob.
protected  class OracleLobHandler.OracleLobCreator
          LobCreator implementation for Oracle databases.
 
Field Summary
protected  Log logger
           
 
Constructor Summary
OracleLobHandler()
           
 
Method Summary
 InputStream getBlobAsBinaryStream(ResultSet rs, int columnIndex)
          Retrieve the given column as binary stream from the given ResultSet.
 byte[] getBlobAsBytes(ResultSet rs, int columnIndex)
          Retrieve the given column as bytes from the given ResultSet.
 InputStream getClobAsAsciiStream(ResultSet rs, int columnIndex)
          Retrieve the given column as ASCII stream from the given ResultSet.
 Reader getClobAsCharacterStream(ResultSet rs, int columnIndex)
          Retrieve the given column as character stream from the given ResultSet.
 String getClobAsString(ResultSet rs, int columnIndex)
          Retrieve the given column as String from the given ResultSet.
 LobCreator getLobCreator()
          Create a new LobCreator instance, i.e.
protected  void initOracleDriverClasses(Connection con)
          Retrieve the oracle.sql.BLOB and oracle.sql.CLOB classes via reflection, and initialize the values for the DURATION_SESSION and MODE_READWRITE constants defined there.
 void setCache(boolean cache)
          Set whether to cache the temporary LOB in the buffer cache.
 void setNativeJdbcExtractor(NativeJdbcExtractor nativeJdbcExtractor)
          Set an appropriate NativeJdbcExtractor to be able to retrieve the underlying native oracle.jdbc.OracleConnection.
 
Methods inherited from class org.springframework.jdbc.support.lob.AbstractLobHandler
getBlobAsBinaryStream, getBlobAsBytes, getClobAsAsciiStream, getClobAsCharacterStream, getClobAsString
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

logger

protected final Log logger
Constructor Detail

OracleLobHandler

public OracleLobHandler()
Method Detail

setNativeJdbcExtractor

public void setNativeJdbcExtractor(NativeJdbcExtractor nativeJdbcExtractor)
Set an appropriate NativeJdbcExtractor to be able to retrieve the underlying native oracle.jdbc.OracleConnection. This is necessary for DataSource-based connection pools, as those need to return wrapped JDBC Connection handles that cannot be cast to a native Connection implementation.

Effectively, this LobHandler just invokes a single NativeJdbcExtractor method, namely getNativeConnectionFromStatement with a PreparedStatement argument (falling back to a PreparedStatement.getConnection() call if no extractor is set).

A common choice is SimpleNativeJdbcExtractor, whose Connection unwrapping (which is what OracleLobHandler needs) will work with many connection pools. See SimpleNativeJdbcExtractor's javadoc for details.

See Also:
NativeJdbcExtractor.getNativeConnectionFromStatement(java.sql.Statement), SimpleNativeJdbcExtractor, oracle.jdbc.OracleConnection

setCache

public void setCache(boolean cache)
Set whether to cache the temporary LOB in the buffer cache. This value will be passed into BLOB/CLOB.createTemporary. Default is "true".

See Also:
oracle.sql.BLOB#createTemporary, oracle.sql.CLOB#createTemporary

initOracleDriverClasses

protected void initOracleDriverClasses(Connection con)
Retrieve the oracle.sql.BLOB and oracle.sql.CLOB classes via reflection, and initialize the values for the DURATION_SESSION and MODE_READWRITE constants defined there.

Parameters:
con - the Oracle Connection, for using the exact same class loader that the Oracle driver was loaded with
See Also:
oracle.sql.BLOB#DURATION_SESSION, oracle.sql.BLOB#MODE_READWRITE, oracle.sql.CLOB#DURATION_SESSION, oracle.sql.CLOB#MODE_READWRITE

getBlobAsBytes

public byte[] getBlobAsBytes(ResultSet rs,
                             int columnIndex)
                      throws SQLException
Description copied from interface: LobHandler
Retrieve the given column as bytes from the given ResultSet. Might simply invoke ResultSet.getBytes or work with ResultSet.getBlob, depending on the database and driver.

Parameters:
rs - the ResultSet to retrieve the content from
columnIndex - the column index to use
Returns:
the content as byte array, or null in case of SQL NULL
Throws:
SQLException - if thrown by JDBC methods
See Also:
ResultSet.getBytes(int)

getBlobAsBinaryStream

public InputStream getBlobAsBinaryStream(ResultSet rs,
                                         int columnIndex)
                                  throws SQLException
Description copied from interface: LobHandler
Retrieve the given column as binary stream from the given ResultSet. Might simply invoke ResultSet.getBinaryStream or work with ResultSet.getBlob, depending on the database and driver.

Parameters:
rs - the ResultSet to retrieve the content from
columnIndex - the column index to use
Returns:
the content as binary stream, or null in case of SQL NULL
Throws:
SQLException - if thrown by JDBC methods
See Also:
ResultSet.getBinaryStream(int)

getClobAsString

public String getClobAsString(ResultSet rs,
                              int columnIndex)
                       throws SQLException
Description copied from interface: LobHandler
Retrieve the given column as String from the given ResultSet. Might simply invoke ResultSet.getString or work with ResultSet.getClob, depending on the database and driver.

Parameters:
rs - the ResultSet to retrieve the content from
columnIndex - the column index to use
Returns:
the content as String, or null in case of SQL NULL
Throws:
SQLException - if thrown by JDBC methods
See Also:
ResultSet.getString(int)

getClobAsAsciiStream

public InputStream getClobAsAsciiStream(ResultSet rs,
                                        int columnIndex)
                                 throws SQLException
Description copied from interface: LobHandler
Retrieve the given column as ASCII stream from the given ResultSet. Might simply invoke ResultSet.getAsciiStream or work with ResultSet.getClob, depending on the database and driver.

Parameters:
rs - the ResultSet to retrieve the content from
columnIndex - the column index to use
Returns:
the content as ASCII stream, or null in case of SQL NULL
Throws:
SQLException - if thrown by JDBC methods
See Also:
ResultSet.getAsciiStream(int)

getClobAsCharacterStream

public Reader getClobAsCharacterStream(ResultSet rs,
                                       int columnIndex)
                                throws SQLException
Description copied from interface: LobHandler
Retrieve the given column as character stream from the given ResultSet. Might simply invoke ResultSet.getCharacterStream or work with ResultSet.getClob, depending on the database and driver.

Parameters:
rs - the ResultSet to retrieve the content from
columnIndex - the column index to use
Returns:
the content as character stream
Throws:
SQLException - if thrown by JDBC methods
See Also:
ResultSet.getCharacterStream(int)

getLobCreator

public LobCreator getLobCreator()
Description copied from interface: LobHandler
Create a new LobCreator instance, i.e. a session for creating BLOBs and CLOBs. Needs to be closed after the created LOBs are not needed anymore - typically after statement execution or transaction completion.

Returns:
the new LobCreator instance
See Also:
LobCreator.close()