org.postgresql.largeobject
Class LargeObjectManager

java.lang.Object
  org.postgresql.largeobject.LargeObjectManager

public class LargeObjectManager
extends java.lang.Object

This class implements the large object interface to org.postgresql.

It provides methods that allow client code to create, open and delete large objects from the database. When opening an object, an instance of org.postgresql.largeobject.LargeObject is returned, and its methods then allow access to the object.

This class can only be created by org.postgresql.Connection

To get access to this class, use the following segment of code:

 import org.postgresql.largeobject.*;

 Connection  conn;
 LargeObjectManager lobj;

 ... code that opens a connection ...

 lobj = ((org.postgresql.PGConnection)myconn).getLargeObjectAPI();
 

Normally, client code would use the getAsciiStream, getBinaryStream, or getUnicodeStream methods in ResultSet, or setAsciiStream, setBinaryStream, or setUnicodeStream methods in PreparedStatement to access Large Objects.

However, sometimes lower level access to Large Objects are required, that are not supported by the JDBC specification.

Refer to org.postgresql.largeobject.LargeObject on how to manipulate the contents of a Large Object.

See Also:

ResultSet.getAsciiStream(int), ResultSet.getBinaryStream(int), ResultSet.getUnicodeStream(int), PreparedStatement.setAsciiStream(int, java.io.InputStream, int), PreparedStatement.setBinaryStream(int, java.io.InputStream, int), PreparedStatement.setUnicodeStream(int, java.io.InputStream, int)

Field Summary

static int	READ This mode indicates we want to read an object
static int	READWRITE This mode is the default.
static int	WRITE This mode indicates we want to write to an object

Constructor Summary

LargeObjectManager(org.postgresql.core.BaseConnection conn)
Constructs the LargeObject API.

Method Summary

int	create() Deprecated. As of 8.3, replaced by createLO()
int	create(int mode) Deprecated. As of 8.3, replaced by createLO(int)
long	createLO() This creates a large object, returning its OID.
long	createLO(int mode) This creates a large object, returning its OID
void	delete(int oid) Deprecated. As of 8.3, replaced by delete(long)
void	delete(long oid) This deletes a large object.
LargeObject	open(int oid) Deprecated. As of 8.3, replaced by open(long)
LargeObject	open(int oid, boolean commitOnClose) This opens an existing large object, same as previous method, but commits the transaction on close if asked.
LargeObject	open(int oid, int mode) Deprecated. As of 8.3, replaced by open(long, int)
LargeObject	open(int oid, int mode, boolean commitOnClose) This opens an existing large object, same as previous method, but commits the transaction on close if asked
LargeObject	open(long oid) This opens an existing large object, based on its OID.
LargeObject	open(long oid, boolean commitOnClose) This opens an existing large object, same as previous method, but commits the transaction on close if asked
LargeObject	open(long oid, int mode) This opens an existing large object, based on its OID
LargeObject	open(long oid, int mode, boolean commitOnClose) This opens an existing large object, based on its OID
void	unlink(int oid) Deprecated. As of 8.3, replaced by unlink(long)
void	unlink(long oid) This deletes a large object.

Methods inherited from class java.lang.Object

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

Field Detail

WRITE

public static final int WRITE

This mode indicates we want to write to an object

See Also:

Constant Field Values

READ

public static final int READ

This mode indicates we want to read an object

See Also:

Constant Field Values

READWRITE

public static final int READWRITE

This mode is the default. It indicates we want read and write access to a large object

See Also:

Constant Field Values

Constructor Detail

LargeObjectManager

public LargeObjectManager(org.postgresql.core.BaseConnection conn)
                   throws java.sql.SQLException

Constructs the LargeObject API.

Important Notice
This method should only be called by org.postgresql.Connection

There should only be one LargeObjectManager per Connection. The org.postgresql.Connection class keeps track of the various extension API's and it's advised you use those to gain access, and not going direct.

Throws:

java.sql.SQLException

Method Detail

open

public LargeObject open(int oid)
                 throws java.sql.SQLException

Deprecated. As of 8.3, replaced by open(long)

This opens an existing large object, based on its OID. This method assumes that READ and WRITE access is required (the default).

Parameters:

oid - of large object

Returns:

LargeObject instance providing access to the object

Throws:

java.sql.SQLException - on error

open

public LargeObject open(int oid,
                        boolean commitOnClose)
                 throws java.sql.SQLException

This opens an existing large object, same as previous method, but commits the transaction on close if asked. This is useful when the LOB is returned to a caller which won't take care of transactions by itself.

Parameters:

oid - of large object

commitOnClose - commit the transaction when this LOB will be closed

Returns:

LargeObject instance providing access to the object

Throws:

java.sql.SQLException - on error

open

public LargeObject open(long oid)
                 throws java.sql.SQLException

This opens an existing large object, based on its OID. This method assumes that READ and WRITE access is required (the default).

Parameters:

oid - of large object

Returns:

LargeObject instance providing access to the object

Throws:

java.sql.SQLException - on error

open

public LargeObject open(long oid,
                        boolean commitOnClose)
                 throws java.sql.SQLException

This opens an existing large object, same as previous method, but commits the transaction on close if asked

Parameters:

oid - of large object

commitOnClose - commit the transaction when this LOB will be closed

Returns:

LargeObject instance providing access to the object

Throws:

java.sql.SQLException - on error

open

public LargeObject open(int oid,
                        int mode)
                 throws java.sql.SQLException

Deprecated. As of 8.3, replaced by open(long, int)

This opens an existing large object, based on its OID

Parameters:

oid - of large object

mode - mode of open

Returns:

LargeObject instance providing access to the object

Throws:

java.sql.SQLException - on error

open

public LargeObject open(int oid,
                        int mode,
                        boolean commitOnClose)
                 throws java.sql.SQLException

This opens an existing large object, same as previous method, but commits the transaction on close if asked

Parameters:

oid - of large object

mode - mode of open

commitOnClose - commit the transaction when this LOB will be closed

Returns:

LargeObject instance providing access to the object

Throws:

java.sql.SQLException - on error

open

public LargeObject open(long oid,
                        int mode)
                 throws java.sql.SQLException

This opens an existing large object, based on its OID

Parameters:

oid - of large object

mode - mode of open

Returns:

LargeObject instance providing access to the object

Throws:

java.sql.SQLException - on error

open

public LargeObject open(long oid,
                        int mode,
                        boolean commitOnClose)
                 throws java.sql.SQLException

This opens an existing large object, based on its OID

Parameters:

oid - of large object

mode - mode of open

commitOnClose - commit the transaction when this LOB will be closed

Returns:

LargeObject instance providing access to the object

Throws:

java.sql.SQLException - on error

create

public int create()
           throws java.sql.SQLException

Deprecated. As of 8.3, replaced by createLO()

This creates a large object, returning its OID.

It defaults to READWRITE for the new object's attributes.

Returns:

oid of new object

Throws:

java.sql.SQLException - on error

createLO

public long createLO()
              throws java.sql.SQLException

This creates a large object, returning its OID.

It defaults to READWRITE for the new object's attributes.

Returns:

oid of new object

Throws:

java.sql.SQLException

createLO

public long createLO(int mode)
              throws java.sql.SQLException

This creates a large object, returning its OID

Parameters:

mode - a bitmask describing different attributes of the new object

Returns:

oid of new object

Throws:

java.sql.SQLException - on error

create

public int create(int mode)
           throws java.sql.SQLException

Deprecated. As of 8.3, replaced by createLO(int)

This creates a large object, returning its OID

Parameters:

mode - a bitmask describing different attributes of the new object

Returns:

oid of new object

Throws:

java.sql.SQLException - on error

delete

public void delete(long oid)
            throws java.sql.SQLException

This deletes a large object.

Parameters:

oid - describing object to delete

Throws:

java.sql.SQLException - on error

unlink

public void unlink(int oid)
            throws java.sql.SQLException

Deprecated. As of 8.3, replaced by unlink(long)

This deletes a large object.

It is identical to the delete method, and is supplied as the C API uses unlink.

Parameters:

oid - describing object to delete

Throws:

java.sql.SQLException - on error

unlink

public void unlink(long oid)
            throws java.sql.SQLException

This deletes a large object.

It is identical to the delete method, and is supplied as the C API uses unlink.

Parameters:

oid - describing object to delete

Throws:

java.sql.SQLException - on error

delete

public void delete(int oid)
            throws java.sql.SQLException

Deprecated. As of 8.3, replaced by delete(long)

This deletes a large object.

Parameters:

oid - describing object to delete

Throws:

java.sql.SQLException - on error