Class BlobImpl

java.lang.Object

org.datanucleus.store.rdbms.mapping.column.BlobImpl

All Implemented Interfaces:

Blob

public class BlobImpl
extends Object
implements Blob

The representation (mapping) in the Java programming language of an SQL BLOB value. An SQL BLOB is a built-in type that stores a Binary Large Object as a column value in a row of a database table. The driver implements Blob using an SQL locator(BLOB), which means that a Blob object contains a logical pointer to the SQL BLOB data rather than the data itself. A Blob object is valid for the duration of the transaction in which is was created.

Methods in the interfaces ResultSet, CallableStatement, and PreparedStatement, such as getBlob and setBlob allow a programmer to access an SQL BLOB value. The Blob interface provides methods for getting the length of an SQL BLOB (Binary Large Object) value, for materializing a BLOB value on the client, and for determining the position of a pattern of bytes within a BLOB value.

Field Summary

Fields

Modifier and Type	Field	Description
private byte[]	bytes
(package private) boolean	freed	Whether we have already freed resources.
private int	length
private InputStream	stream

Constructor Summary

Constructors

Constructor	Description
BlobImpl(byte[] bytes)	Constructor taking a byte array.
BlobImpl(InputStream stream)	Constructor taking an InputStream.
BlobImpl(Object obj)	Constructor taking a serialised object.

Method Summary

Modifier and Type	Method	Description
void	free()	Free the Blob object and releases the resources that it holds.
InputStream	getBinaryStream()
InputStream	getBinaryStream(long pos, long length)	Returns an InputStream object that contains a partial Blob value, starting with the byte specified by pos, which is length bytes in length.
byte[]	getBytes(long pos, int length)
Object	getObject()	Accessor for the Object.
long	length()
long	position(byte[] pattern, long start)
long	position(Blob pattern, long start)
OutputStream	setBinaryStream(long value)
int	setBytes(long value, byte[] bytes)
int	setBytes(long value, byte[] bytes, int pos, int length)
void	truncate(long value)

Methods inherited from class Object

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

Field Details

stream

private InputStream stream

length

private int length

bytes

private byte[] bytes

freed

boolean freed

Whether we have already freed resources.

Constructor Details

BlobImpl

public BlobImpl(Object obj)
         throws IOException

Constructor taking a serialised object.

Parameters:

obj - The serialised object.

Throws:

IOException - if an error occurs

BlobImpl

public BlobImpl(byte[] bytes)

Constructor taking a byte array.

Parameters:

bytes - The byte array

BlobImpl

public BlobImpl(InputStream stream)

Constructor taking an InputStream.

Parameters:

stream - The InputStream

Method Details

getObject

public Object getObject()
                 throws SQLException

Accessor for the Object.

Returns:

The object.

Throws:

SQLException - if an error occurs

length

public long length()
            throws SQLException

Specified by:

length in interface Blob

Throws:

SQLException

getBytes

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

Specified by:

getBytes in interface Blob

Throws:

SQLException

setBytes

public int setBytes(long value,
 byte[] bytes,
 int pos,
 int length)
             throws SQLException

Specified by:

setBytes in interface Blob

Throws:

SQLException

truncate

public void truncate(long value)
              throws SQLException

Specified by:

truncate in interface Blob

Throws:

SQLException

setBytes

public int setBytes(long value,
 byte[] bytes)
             throws SQLException

Specified by:

setBytes in interface Blob

Throws:

SQLException

getBinaryStream

public InputStream getBinaryStream()
                            throws SQLException

Specified by:

getBinaryStream in interface Blob

Throws:

SQLException

getBinaryStream

public InputStream getBinaryStream(long pos,
 long length)
                            throws SQLException

Returns an InputStream object that contains a partial Blob value, starting with the byte specified by pos, which is length bytes in length.

Specified by:

getBinaryStream in interface Blob

Parameters:

pos - the offset to the first byte of the partial value to be retrieved. The first byte in the Blob is at position 1

length - the length in bytes of the partial value to be retrieved

Throws:

SQLException

setBinaryStream

public OutputStream setBinaryStream(long value)
                             throws SQLException

Specified by:

setBinaryStream in interface Blob

Throws:

SQLException

free

public void free()
          throws SQLException

Free the Blob object and releases the resources that it holds. The object is invalid once the free method is called.

Specified by:

free in interface Blob

Throws:

SQLException - if an error occurs

position

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

Specified by:

position in interface Blob

Throws:

SQLException

position

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

Specified by:

position in interface Blob

Throws:

SQLException