org.apache.cayenne.util
Class MemoryBlob

java.lang.Object
  org.apache.cayenne.util.MemoryBlob

All Implemented Interfaces:

java.sql.Blob

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

A Blob implementation that stores content in memory.

This implementation is based on jdbcBlob from HSQLDB (copyright HSQL Development Group).

Since:

1.2

Author:

Andrus Adamchik, based on HSQLDB jdbcBlob.

Constructor Summary

MemoryBlob()

MemoryBlob(byte[] data)
Constructs a new MemoryBlob instance wrapping the given octet sequence.

Method Summary

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.
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.
java.io.OutputStream	setBinaryStream(long pos) Always throws an exception.
int	setBytes(long pos, byte[] bytes) Always throws an exception.
int	setBytes(long pos, byte[] bytes, int offset, int len) Always throws an exception.
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

Constructor Detail

MemoryBlob

public MemoryBlob()

MemoryBlob

public MemoryBlob(byte[] data)

Constructs a new MemoryBlob instance wrapping the given octet sequence.

Parameters:

data - the octet sequence representing the Blob value

Throws:

CayenneRuntimeException - if the argument is null

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

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.

The official specification is ambiguous in that it does not precisely indicate the policy to be observed when pos > this.length() - length. One policy would be to retrieve the octets from pos to this.length(). Another would be to throw an exception. This implementation observes the later policy.

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

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

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

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

setBytes

public int setBytes(long pos,
                    byte[] bytes)
             throws java.sql.SQLException

Always throws an exception.

Specified by:

setBytes in interface java.sql.Blob

Throws:

java.sql.SQLException

setBytes

public int setBytes(long pos,
                    byte[] bytes,
                    int offset,
                    int len)
             throws java.sql.SQLException

Always throws an exception.

Specified by:

setBytes in interface java.sql.Blob

Throws:

java.sql.SQLException

setBinaryStream

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

Always throws an exception.

Specified by:

setBinaryStream in interface java.sql.Blob

Throws:

java.sql.SQLException

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