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org.postgresql.largeobject
Class LargeObjectManager

java.lang.Object
  extended by 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
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(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(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
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