org.apache.cayenne.util
Class MemoryBlob

java.lang.Object
  extended by org.apache.cayenne.util.MemoryBlob
All Implemented Interfaces:
Blob

public class MemoryBlob
extends Object
implements Blob

A Blob implementation that stores content in memory.

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

Since:
1.2

Constructor Summary
MemoryBlob()
           
MemoryBlob(byte[] data)
          Constructs a new MemoryBlob instance wrapping the given octet sequence.
 
Method Summary
 void free()
           
 InputStream getBinaryStream()
          Retrieves the BLOB value designated by this Blob instance as a stream.
 InputStream getBinaryStream(long arg0, long arg1)
           
 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(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.
 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 SQLException
Returns the number of bytes in the BLOB value designated by this Blob object.

Specified by:
length in interface Blob
Returns:
length of the BLOB in bytes
Throws:
SQLException - if there is an error accessing the length of the BLOB

getBytes

public byte[] getBytes(long pos,
                       int length)
                throws 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 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:
SQLException - if there is an error accessing the BLOB value

getBinaryStream

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

Specified by:
getBinaryStream in interface Blob
Returns:
a stream containing the BLOB data
Throws:
SQLException - if there is an error accessing the BLOB value

position

public long position(byte[] pattern,
                     long start)
              throws 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 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:
SQLException - if there is an error accessing the BLOB

position

public long position(Blob pattern,
                     long start)
              throws 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 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:
SQLException - if there is an error accessing the BLOB value

setBytes

public int setBytes(long pos,
                    byte[] bytes)
             throws SQLException
Always throws an exception.

Specified by:
setBytes in interface Blob
Throws:
SQLException

setBytes

public int setBytes(long pos,
                    byte[] bytes,
                    int offset,
                    int len)
             throws SQLException
Always throws an exception.

Specified by:
setBytes in interface Blob
Throws:
SQLException

setBinaryStream

public OutputStream setBinaryStream(long pos)
                             throws SQLException
Always throws an exception.

Specified by:
setBinaryStream in interface Blob
Throws:
SQLException

truncate

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

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

free

public void free()
          throws SQLException
Specified by:
free in interface Blob
Throws:
SQLException
Since:
3.0

getBinaryStream

public InputStream getBinaryStream(long arg0,
                                   long arg1)
                            throws SQLException
Specified by:
getBinaryStream in interface Blob
Throws:
SQLException
Since:
3.0


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