org.sourceforge.jxdbcon.postgresql
Class PGBlob

java.lang.Object
  |
  +--org.sourceforge.jxutil.sql.type.AbstractBLOB
        |
        +--org.sourceforge.jxdbcon.postgresql.PGBlob

All Implemented Interfaces:

Blob

public final class PGBlob

extends AbstractBLOB

The PGBlob class implements Blobs. Blobs are only available in Transactions. You need to set the connection's autoCommit feature to false. In PostgreSQL there is no real Blob type, the oid type is used for this purpose. This implementation supports both reading and writing existing blobs.

Version:

$Revision: 1.5 $

Author:

Keve Müller

Field Summary

private Connection	conn Our connection.
private int	handle The Large Object handle.
private static int	INV_READ
private static int	INV_WRITE
private long	objOid The object oid.
private CallableStatement	read Readily prepared call to the read function.
private CallableStatement	seek Readily prepared call to the seek function.
private static int	SEEK_CUR
private static int	SEEK_END
private static int	SEEK_SET
private CallableStatement	write Readily prepared call to the write function.

Constructor Summary

PGBlob(Connection conn)
Initialise the blob with the connection, create a new oid.

PGBlob(Connection conn, long objOid)
Initialise the blob with the connection and the oid.

Method Summary

void	close() Close the LOB handle.
byte[]	getBytes(long pos, int length) Get a chunk of data.
long	getObjOid()
long	length() Determine Large Object's length.
long	position(Blob pattern, long start) Not implemented.
long	position(byte[] pattern, long start) Not implemented.
(package private) void	prepareCalls() Prepare the calls to the lo_lseek, loread and lowrite functions.
int	setBytes(long pos, byte[] data) Write a chunk of data.
int	setBytes(long pos, byte[] data, int spos, int len) Write a chunk of data.
String	toString() for debugging purposes.
void	truncate(long x) Not implemented.

Methods inherited from class org.sourceforge.jxutil.sql.type.AbstractBLOB

getBinaryStream, setBinaryStream

Methods inherited from class java.lang.Object

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

Field Detail

conn

private Connection conn

Our connection.

handle

private int handle

The Large Object handle.

INV_READ

private static final int INV_READ

See Also:

Constant Field Values

INV_WRITE

private static final int INV_WRITE

See Also:

Constant Field Values

objOid

private long objOid

The object oid.

read

private CallableStatement read

Readily prepared call to the read function.

seek

private CallableStatement seek

Readily prepared call to the seek function.

SEEK_CUR

private static final int SEEK_CUR

See Also:

Constant Field Values

SEEK_END

private static final int SEEK_END

See Also:

Constant Field Values

SEEK_SET

private static final int SEEK_SET

See Also:

Constant Field Values

write

private CallableStatement write

Readily prepared call to the write function.

Constructor Detail

PGBlob

public PGBlob(Connection conn)
       throws SQLException

Initialise the blob with the connection, create a new oid. This will call lo_create to create the new oid and lo_open to obtain a handle to the Large Object. Furthermore it prepares the calls to the seek/read/write functions.

PGBlob

public PGBlob(Connection conn,
              long objOid)
       throws SQLException

Initialise the blob with the connection and the oid. This will call lo_open to obtain a handle to the Large Object. Furthermore it prepares the calls to the seek/read/write functions.

Method Detail

close

public void close()
           throws SQLException

Close the LOB handle.

SQLException

getBytes

public byte[] getBytes(long pos,
                       int length)
                throws SQLException

Get a chunk of data. First seeks to the position, then reads the data.

SQLException

getObjOid

public long getObjOid()

length

public long length()
            throws SQLException

Determine Large Object's length. Seek to end, and tell the position.

SQLException

position

public long position(Blob pattern,
                     long start)
              throws SQLException

Not implemented.

SQLException

position

public long position(byte[] pattern,
                     long start)
              throws SQLException

Not implemented.

SQLException

prepareCalls

void prepareCalls()
            throws SQLException

Prepare the calls to the lo_lseek, loread and lowrite functions.

SQLException

setBytes

public int setBytes(long pos,
                    byte[] data)
             throws SQLException

Write a chunk of data. First seeks to the position, then writes the data.

Specified by:

setBytes in interface Blob

Specified by:

setBytes in class AbstractBLOB

SQLException

setBytes

public int setBytes(long pos,
                    byte[] data,
                    int spos,
                    int len)
             throws SQLException

Write a chunk of data. First seeks to the position, then writes the data.

SQLException

toString

public String toString()

for debugging purposes.

Overrides:

toString in class Object

truncate

public void truncate(long x)
              throws SQLException

Not implemented.

SQLException