org.postgresql.largeobject

Class LargeObjectManager

java.lang.Object

org.postgresql.largeobject.LargeObjectManager

public class LargeObjectManager
extends 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 BaseConnection

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

Fields

Modifier and Type	Field and Description
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

Constructors

Constructor and Description
LargeObjectManager(BaseConnection conn) Constructs the LargeObject API.

Method Summary

Methods

Modifier and Type	Method and Description
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(BaseConnection conn)
                   throws SQLException

Constructs the LargeObject API.

Important Notice
This method should only be called by BaseConnection

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

Parameters:

conn - connection

Throws:

SQLException - if something wrong happens

Method Detail

open

@Deprecated
public LargeObject open(int oid)
                 throws 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:

SQLException - on error

open

public LargeObject open(int oid,
               boolean commitOnClose)
                 throws 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:

SQLException - on error

open

public LargeObject open(long oid)
                 throws 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:

SQLException - on error

open

public LargeObject open(long oid,
               boolean commitOnClose)
                 throws 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:

SQLException - on error

open

@Deprecated
public LargeObject open(int oid,
                          int mode)
                 throws 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:

SQLException - on error

open

public LargeObject open(int oid,
               int mode,
               boolean commitOnClose)
                 throws 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:

SQLException - on error

open

public LargeObject open(long oid,
               int mode)
                 throws 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:

SQLException - on error

open

public LargeObject open(long oid,
               int mode,
               boolean commitOnClose)
                 throws 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:

SQLException - on error

create

@Deprecated
public int create()
           throws 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:

SQLException - on error

createLO

public long createLO()
              throws 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:

SQLException - if something wrong happens

createLO

public long createLO(int mode)
              throws 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:

SQLException - on error

create

@Deprecated
public int create(int mode)
           throws 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:

SQLException - on error

delete

public void delete(long oid)
            throws SQLException

This deletes a large object.

Parameters:

oid - describing object to delete

Throws:

SQLException - on error

unlink

@Deprecated
public void unlink(int oid)
            throws 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:

SQLException - on error

unlink

public void unlink(long oid)
            throws 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:

SQLException - on error

delete

@Deprecated
public void delete(int oid)
            throws SQLException

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

This deletes a large object.

Parameters:

oid - describing object to delete

Throws:

SQLException - on error