org.objectweb.cjdbc.driver
Class Blob

java.lang.Object
  extended byorg.objectweb.cjdbc.driver.Blob
All Implemented Interfaces:
java.sql.Blob

public class Blob
extends java.lang.Object
implements java.sql.Blob

The representation (mapping) in the JavaTM 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. 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. 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. In addition, this interface has methods for updating a BLOB value.

Since:
JDK 1.2
Author:
Emmanuel Cecchet, Nicolas Modrzyk

Field Summary
(package private)  byte[] binaryData
          The binary data that makes up this BLOB.
 
Constructor Summary
Blob(byte[] data)
          Creates a new Blob instance.
 
Method Summary
protected static java.lang.String data2hex(byte[] data)
          Convert data into hexa
(package private) static byte[] escapeblock(byte[] buf, int size)
          Convert the data into hexa format so we can pass it as a string to the database.
 java.io.InputStream getBinaryStream()
          Retrieves the BLOB value designated by this Blob instance as a stream.
 byte[] getBytes(long pos, int length)
          Retrieves all or part of the BLOB value that this Blob object represents, as an array of bytes.
protected static byte[] hex2data(java.lang.String str)
          convert hexa into data
 long length()
          Returns the number of bytes in the BLOB value designated by this Blob object.
 long position(java.sql.Blob pattern, long start)
          Retrieves the byte position in the BLOB value designated by this Blob object at which pattern begins.
 long position(byte[] pattern, long start)
          Retrieves the byte position at which the specified byte array pattern begins within the BLOB value that this Blob object represents.
(package private) static byte[] rescapeblock(byte[] buf)
          Reconvert the original data of the buffer by re-converting all the hexa data into bytes.
 java.io.OutputStream setBinaryStream(long pos)
          Retrieves a stream that can be used to write to the BLOB value that this Blob object represents.
 int setBytes(long pos, byte[] bytes)
          Writes the given array of bytes to the BLOB value that this Blob object represents, starting at position pos, and returns the number of bytes written.
 int setBytes(long pos, byte[] bytes, int offset, int len)
          Writes all or part of the given byte array to the BLOB value that this Blob object represents and returns the number of bytes written.
private static byte toDataNibble(char c)
          convert hexa char to byte value
private static char toHexChar(int i)
          convert value to hexa value
 void truncate(long len)
          Truncates the BLOB value that this Blob object represents to be len bytes in length.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

binaryData

byte[] binaryData
The binary data that makes up this BLOB.

Constructor Detail

Blob

public Blob(byte[] data)
Creates a new Blob instance.

Parameters:
data - an byte array
Method Detail

length

public long length()
            throws java.sql.SQLException
Returns the number of bytes in the BLOB value designated by this Blob object.

Specified by:
length in interface java.sql.Blob
Returns:
length of the BLOB in bytes
Throws:
java.sql.SQLException - if there is an error accessing the length of the BLOB
Since:
JDK 1.2

getBytes

public byte[] getBytes(long pos,
                       int length)
                throws java.sql.SQLException
Retrieves all or part of the BLOB value that this Blob object represents, as an array of bytes. This byte array contains up to length consecutive bytes starting at position pos.

Specified by:
getBytes in interface java.sql.Blob
Parameters:
pos - the ordinal position of the first byte in the BLOB value to be extracted; the first byte is at position 1
length - the number of consecutive bytes to be copied
Returns:
a byte array containing up to length consecutive bytes from the BLOB value designated by this Blob object, starting with the byte at position pos
Throws:
java.sql.SQLException - if there is an error accessing the BLOB value
Since:
JDK 1.2
See Also:
setBytes(long, byte[])

getBinaryStream

public java.io.InputStream getBinaryStream()
                                    throws java.sql.SQLException
Retrieves the BLOB value designated by this Blob instance as a stream.

Specified by:
getBinaryStream in interface java.sql.Blob
Returns:
a stream containing the BLOB data
Throws:
java.sql.SQLException - if there is an error accessing the BLOB value
Since:
JDK 1.2
See Also:
setBinaryStream(long)

position

public long position(byte[] pattern,
                     long start)
              throws java.sql.SQLException
Retrieves the byte position at which the specified byte array pattern begins within the BLOB value that this Blob object represents. The search for pattern begins at position start.

Specified by:
position in interface java.sql.Blob
Parameters:
pattern - the byte array for which to search
start - the position at which to begin searching; the first position is 1
Returns:
the position at which the pattern appears, else -1
Throws:
java.sql.SQLException - if there is an error accessing the BLOB
Since:
JDK 1.2

position

public long position(java.sql.Blob pattern,
                     long start)
              throws java.sql.SQLException
Retrieves the byte position in the BLOB value designated by this Blob object at which pattern begins. The search begins at position start.

Specified by:
position in interface java.sql.Blob
Parameters:
pattern - the Blob object designating the BLOB value for which to search
start - the position in the BLOB value at which to begin searching; the first position is 1
Returns:
the position at which the pattern begins, else -1
Throws:
java.sql.SQLException - if there is an error accessing the BLOB value
Since:
JDK 1.2

setBytes

public int setBytes(long pos,
                    byte[] bytes)
             throws java.sql.SQLException
Writes the given array of bytes to the BLOB value that this Blob object represents, starting at position pos, and returns the number of bytes written.

Specified by:
setBytes in interface java.sql.Blob
Parameters:
pos - the position in the BLOB object at which to start writing
bytes - the array of bytes to be written to the BLOB value that this Blob object represents
Returns:
the number of bytes written
Throws:
java.sql.SQLException - if there is an error accessing the BLOB value
Since:
JDK 1.4
See Also:
getBytes(long, int)

setBytes

public int setBytes(long pos,
                    byte[] bytes,
                    int offset,
                    int len)
             throws java.sql.SQLException
Writes all or part of the given byte array to the BLOB value that this Blob object represents and returns the number of bytes written. Writing starts at position pos in the BLOB value; len bytes from the given byte array are written.

Specified by:
setBytes in interface java.sql.Blob
Parameters:
pos - the position in the BLOB object at which to start writing
bytes - the array of bytes to be written to this BLOB object
offset - the offset into the array bytes at which to start reading the bytes to be set
len - the number of bytes to be written to the BLOB value from the array of bytes bytes
Returns:
the number of bytes written
Throws:
java.sql.SQLException - if there is an error accessing the BLOB value
Since:
JDK 1.4
See Also:
getBytes(long, int)

setBinaryStream

public java.io.OutputStream setBinaryStream(long pos)
                                     throws java.sql.SQLException
Retrieves a stream that can be used to write to the BLOB value that this Blob object represents. The stream begins at position pos.

Specified by:
setBinaryStream in interface java.sql.Blob
Parameters:
pos - the position in the BLOB value at which to start writing
Returns:
a java.io.OutputStream object to which data can be written
Throws:
java.sql.SQLException - if there is an error accessing the BLOB value
Since:
JDK 1.4
See Also:
getBinaryStream()

truncate

public void truncate(long len)
              throws java.sql.SQLException
Truncates the BLOB value that this Blob object represents to be len bytes in length.

Specified by:
truncate in interface java.sql.Blob
Parameters:
len - the length, in bytes, to which the BLOB value that this Blob object represents should be truncated
Throws:
java.sql.SQLException - if there is an error accessing the BLOB value
Since:
JDK 1.4

escapeblock

static final byte[] escapeblock(byte[] buf,
                                int size)
Convert the data into hexa format so we can pass it as a string to the database.

Parameters:
buf - is the data needed to be converted
size - the size of the buffer to be converted
Returns:
a byte array of a different size with all the data converted in hexa, or null if the buf param was null

rescapeblock

static final byte[] rescapeblock(byte[] buf)
Reconvert the original data of the buffer by re-converting all the hexa data into bytes.

Parameters:
buf - the byte array of data as hexa
Returns:
a byte array of data bytes or null if buf was null

data2hex

protected static java.lang.String data2hex(byte[] data)
Convert data into hexa

Parameters:
data - to convert
Returns:
the converted string

hex2data

protected static byte[] hex2data(java.lang.String str)
convert hexa into data

Parameters:
str - to convert
Returns:
the converted byte array

toHexChar

private static char toHexChar(int i)
convert value to hexa value

Parameters:
i - byte to convert
Returns:
hexa char

toDataNibble

private static byte toDataNibble(char c)
convert hexa char to byte value

Parameters:
c - hexa character
Returns:
corresponding byte value


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