org.objectweb.cjdbc.driver
Class Blob

java.lang.Object
  org.objectweb.cjdbc.driver.Blob

All Implemented Interfaces:

java.sql.Blob, java.io.Serializable

public class Blob

extends java.lang.Object

implements java.sql.Blob, java.io.Serializable

The representation (mapping) in the Java ^TM programming language of an SQL BLOB value. By default drivers implement 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. But since this is highly database-specific, we are unable to do that and implement Blobs using a simple private byte array copy instead. This may consume a lot of memory but this is both portable across databases and even legal from a JDBC standard point of view as long as our method DatabaseMetaData.locatorsUpdateCopy() returns true.

Since:

JDK 1.2

Author:

Marc Herbert

See Also:

Blob, Serialized Form

Field Summary

(package private) byte[]

internalArray The binary data that makes up this BLOB.

Constructor Summary

Blob(byte[] src)
Creates a new Blob object built from a copy of the given byte array.

Method Summary

private void	checkInitialized()
private static void	checkSQLRangeIsSupported(long sqlStart, int len) Checks that indexes (sqlStart) and (sqlStart+len) are correct.
void	free() This method frees the Blob object and releases the resources that it holds.
java.io.InputStream	getBinaryStream()
byte[]	getBytes(long sqlPos, int length)
(package private) byte[]	getInternalByteArray() BlobOutputStream needs it
long	length()
long	position(java.sql.Blob pattern, long sqlStart)
long	position(byte[] pattern, long sqlStart)
private byte[]	resizedByteArray(byte[] src, int srcStart, int newSize) Returns a copy of the byte array argument starting at srcFrom and extended or shortened to newLength. srcFrom index starts from zero (regular style).
java.io.OutputStream	setBinaryStream(long sqlStart)
int	setBytes(long sqlStartPos, byte[] srcArray)
int	setBytes(long sqlStartPos, byte[] srcArray, int srcArrayOffset, int copiedLength)
void	truncate(long newLen)

Methods inherited from class java.lang.Object

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

Field Detail

internalArray

byte[] internalArray

The binary data that makes up this BLOB.

Constructor Detail

Blob

public Blob(byte[] src)

Creates a new Blob object built from a copy of the given byte array.

Parameters:

src - the array to copy

Method Detail

length

public long length()
            throws java.sql.SQLException

Specified by:

length in interface java.sql.Blob

Throws:

java.sql.SQLException

See Also:

Blob.length()

getBytes

public byte[] getBytes(long sqlPos,
                       int length)
                throws java.sql.SQLException

Specified by:

getBytes in interface java.sql.Blob

Throws:

java.sql.SQLException

See Also:

Blob.getBytes(long, int)

getBinaryStream

public java.io.InputStream getBinaryStream()
                                    throws java.sql.SQLException

Specified by:

getBinaryStream in interface java.sql.Blob

Throws:

java.sql.SQLException

See Also:

Blob.getBinaryStream()

position

public long position(byte[] pattern,
                     long sqlStart)
              throws java.sql.SQLException

Specified by:

position in interface java.sql.Blob

Throws:

java.sql.SQLException

See Also:

Blob.position(byte[], long)

position

public long position(java.sql.Blob pattern,
                     long sqlStart)
              throws java.sql.SQLException

Specified by:

position in interface java.sql.Blob

Throws:

java.sql.SQLException

See Also:

Blob.position(java.sql.Blob, long)

setBytes

public int setBytes(long sqlStartPos,
                    byte[] srcArray)
             throws java.sql.SQLException

Specified by:

setBytes in interface java.sql.Blob

Throws:

java.sql.SQLException

See Also:

Blob.setBytes(long, byte[], int, int)

setBytes

public int setBytes(long sqlStartPos,
                    byte[] srcArray,
                    int srcArrayOffset,
                    int copiedLength)
             throws java.sql.SQLException

Specified by:

setBytes in interface java.sql.Blob

Throws:

java.sql.SQLException

See Also:

Blob.setBytes(long, byte[], int, int)

setBinaryStream

public java.io.OutputStream setBinaryStream(long sqlStart)
                                     throws java.sql.SQLException

Specified by:

setBinaryStream in interface java.sql.Blob

Throws:

java.sql.SQLException

See Also:

Blob.setBinaryStream(long)

truncate

public void truncate(long newLen)
              throws java.sql.SQLException

Specified by:

truncate in interface java.sql.Blob

Throws:

java.sql.SQLException

See Also:

Blob.truncate(long)

free

public void free()

This method frees the Blob object and releases the resources that it holds.

getInternalByteArray

byte[] getInternalByteArray()

BlobOutputStream needs it

checkInitialized

private void checkInitialized()
                       throws DriverSQLException

Throws:

DriverSQLException

checkSQLRangeIsSupported

private static void checkSQLRangeIsSupported(long sqlStart,
                                             int len)
                                      throws java.sql.SQLException

Checks that indexes (sqlStart) and (sqlStart+len) are correct. Valid sqlStart begins at 1 (SQL-style). A reasonable sqlEnd of Blob is no more than Integer.MAX_VALUE+1 because we implement using Java arrays. This method is basically a check to use before casting from long to int.

Parameters:

sqlStart - start index

len - length

Throws:

java.sql.SQLException

resizedByteArray

private byte[] resizedByteArray(byte[] src,
                                int srcStart,
                                int newSize)

Returns a copy of the byte array argument starting at srcFrom and extended or shortened to newLength. srcFrom index starts from zero (regular style).

This roughly double the memory used... *sigh* http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4655503 is tagged "fixed" but nothing changed ?!