ewe.io
Class RandomStreamAdapter

java.lang.Object
  ewe.util.Errorable
      ewe.io.BasicStreamObject
          ewe.io.StreamObject
              ewe.io.RandomStreamObject
                  ewe.io.RandomStreamAdapter

All Implemented Interfaces:

BasicRandomAccessStream, BasicStream, BufferedStream, RandomAccessStream, Stream, Streamable, StreamCanPause

public class RandomStreamAdapter

extends RandomStreamObject

implements BufferedStream, StreamCanPause

This provides a full RandomAccessStream implementation from either a BasicRandomAccessStream implementation or from a RandomStream object.

Field Summary

protected RandomStream	rs
protected BasicRandomAccessStream	stream

Fields inherited from class ewe.io.StreamObject

napIterations, napTime, READWRITE_CLOSED, READWRITE_ERROR, READWRITE_WOULDBLOCK

Fields inherited from class ewe.io.BasicStreamObject

closed

Fields inherited from class ewe.util.Errorable

error

Fields inherited from interface ewe.io.StreamCanPause

PAUSE_UNTIL_CAN_READ, PAUSE_UNTIL_CAN_WRITE, PAUSE_UNTIL_CLOSED, PAUSE_UNTIL_FLUSHED

Constructor Summary

protected	RandomStreamAdapter()
	RandomStreamAdapter(BasicRandomAccessStream basicStream)
	RandomStreamAdapter(RandomStream rs)

Method Summary

boolean	canWrite() Tests if the RandomAccessStream was opened in read-write mode as opposed to read-ony mode.
boolean	closeStream() This is non-blocking.
boolean	flushStream() This is non-blocking.
long	getStreamLength() Gets the length of the open stream.
boolean	isOpen() Returns if the stream is open or not.
int	nonBlockingRead(byte[] buff, int start, int count) This calls the nonBlockingRead() of the client BasicStream.
int	nonBlockingRead(long location, byte[] dest, int offset, int length) Non-blocking read at a particular location.
int	nonBlockingWrite(byte[] buff, int start, int count) This calls the nonBlockingWrite() of the client BasicStream.
int	nonBlockingWrite(long location, byte[] src, int offset, int length) Non-blocking write at a particular location.
int	pauseUntilReady(int pauseFor, int value)
boolean	pushback(byte[] bytes, int start, int count) Push back some bytes into the input stream.
boolean	seekPosition(long where) Tell the Stream to move to the specific position.
boolean	setStreamLength(long length) Set the length of the RandomAccessStream if possible.
long	tellPosition() Retrieve the file position.

Methods inherited from class ewe.io.RandomStreamObject

getFilePosition, getLength, length, seek, seek, setLength, tell, toRandomStream

Methods inherited from class ewe.io.StreamObject

close, doRead, doWrite, flush, nap, nap, read, readAByte, readBytes, readBytes, write, writeAByte, writeBytes, writeBytes

Methods inherited from class ewe.io.BasicStreamObject

getException, getName, read, read, throwIOException, toInputStream, toOutputStream, toStream, write, write

Methods inherited from class ewe.util.Errorable

returnError, returnError, returnError

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, toString

Methods inherited from interface ewe.io.Stream

flush, read, read, read, readBytes, readBytes, toInputStream, toOutputStream, write, write, write, writeBytes, writeBytes

Methods inherited from interface ewe.io.BasicStream

close

Field Detail

rs

protected RandomStream rs

stream

protected BasicRandomAccessStream stream

Constructor Detail

RandomStreamAdapter

protected RandomStreamAdapter()

RandomStreamAdapter

public RandomStreamAdapter(BasicRandomAccessStream basicStream)

RandomStreamAdapter

public RandomStreamAdapter(RandomStream rs)

Method Detail

pauseUntilReady

public int pauseUntilReady(int pauseFor,
                           int value)

Specified by:

pauseUntilReady in interface StreamCanPause

pushback

public boolean pushback(byte[] bytes,
                        int start,
                        int count)

Push back some bytes into the input stream. There is no limit on the number of bytes which can be pushed back. This can be called multiple times.

Specified by:

pushback in interface BufferedStream

canWrite

public boolean canWrite()

Description copied from interface: BasicRandomAccessStream

Tests if the RandomAccessStream was opened in read-write mode as opposed to read-ony mode.

Specified by:

canWrite in interface BasicRandomAccessStream

isOpen

public boolean isOpen()

Description copied from interface: BasicStream

Returns if the stream is open or not.

Specified by:

isOpen in interface BasicStream

Overrides:

isOpen in class StreamObject

nonBlockingRead

public int nonBlockingRead(byte[] buff,
                           int start,
                           int count)

This calls the nonBlockingRead() of the client BasicStream.

Specified by:

nonBlockingRead in interface BasicStream

Overrides:

nonBlockingRead in class StreamObject

Parameters:

buff - Destination byte array to hold incoming data.

start - Starting index in buff for incoming data.

count - Maximum number of bytes to read - should never be zero.

Returns:

greater than 0 = Number of bytes read.
0 = No bytes available to read at this time.
-1 = Stream end reached no further bytes to read.
-2 = IO Error.
Note that these values are different to the Stream.readBytes method.

nonBlockingWrite

public int nonBlockingWrite(byte[] buff,
                            int start,
                            int count)

This calls the nonBlockingWrite() of the client BasicStream.

Specified by:

nonBlockingWrite in interface BasicStream

Overrides:

nonBlockingWrite in class StreamObject

Parameters:

buff - Source byte array holding data to be written.

start - Starting index in buff for data to be written.

count - Number of bytes to write - should never be zero.

Returns:

greater than 0 = Number of bytes actually written.
0 = No bytes could be written yet - but the stream is still open.
-1 = Stream has been closed - no further writes are possible.
-2 = IO error - something went wrong.
Note that these values are different to the Stream.writeBytes method.

flushStream

public boolean flushStream()
                    throws IOException

Description copied from interface: BasicStream

This is non-blocking. It returns true if the flush completed, false if it did not, or throws an exception on error.

Specified by:

flushStream in interface BasicStream

Throws:

IOException

closeStream

public boolean closeStream()
                    throws IOException

Description copied from interface: BasicStream

This is non-blocking. It returns true if the close completed, false if it did not, or throws an exception on error.

Specified by:

closeStream in interface BasicStream

Overrides:

closeStream in class StreamObject

Throws:

IOException

setStreamLength

public boolean setStreamLength(long length)
                        throws IOException

Description copied from interface: BasicRandomAccessStream

Set the length of the RandomAccessStream if possible. This is non-blocking, it will return false if the operation is still continuing and true if the operation completed. If the operation could not be performed at all an IOException will be thrown.

Make no assumptions about the success of this method. Not all RAS objects will support setStreamLength() or setLength() - not even all Files on all systems will support this. For example, PersonalJava/Java 1.1 does not support this feature and will throw an IOException.

What happens to the file position pointer after this method is called is unpredictable, especially if you are truncating the file. You should ALWAYS reset the file position pointer after calling this method to be where you wish it to be.

Specified by:

setStreamLength in interface BasicRandomAccessStream

Overrides:

setStreamLength in class RandomStreamObject

Throws:

IOException

getStreamLength

public long getStreamLength()
                     throws IOException

Description copied from class: RandomStreamObject

Gets the length of the open stream. This is non-blocking.

Specified by:

getStreamLength in interface BasicRandomAccessStream

Overrides:

getStreamLength in class RandomStreamObject

Returns:

the length of the stream or -1 if the length is not known yet.

Throws:

IOException - if an error occured while getting the length.

tellPosition

public long tellPosition()
                  throws IOException

Description copied from class: RandomStreamObject

Retrieve the file position. This is non-blocking

Specified by:

tellPosition in interface BasicRandomAccessStream

Overrides:

tellPosition in class RandomStreamObject

Returns:

the position of the stream or -1 if the position is not known yet.

Throws:

IOException - if an error occured while getting the position.

seekPosition

public boolean seekPosition(long where)
                     throws IOException

Description copied from class: RandomStreamObject

Tell the Stream to move to the specific position. This is a non-blocking call.

Specified by:

seekPosition in interface BasicRandomAccessStream

Overrides:

seekPosition in class RandomStreamObject

Parameters:

where - The position to seek to.

Returns:

true if the seek completed successfully, false if the seek did not complete yet.

Throws:

IOException - if an error occured during the seek.

nonBlockingRead

public int nonBlockingRead(long location,
                           byte[] dest,
                           int offset,
                           int length)
                    throws IOException

Description copied from interface: BasicRandomAccessStream

Non-blocking read at a particular location. Used if there are multiple threads reading/writing to a RandomAccessStream.

Specified by:

nonBlockingRead in interface BasicRandomAccessStream

Overrides:

nonBlockingRead in class RandomStreamObject

Throws:

IOException

nonBlockingWrite

public int nonBlockingWrite(long location,
                            byte[] src,
                            int offset,
                            int length)
                     throws IOException

Description copied from interface: BasicRandomAccessStream

Non-blocking write at a particular location. Used if there are multiple threads reading/writing to a RandomAccessStream.

Specified by:

nonBlockingWrite in interface BasicRandomAccessStream

Overrides:

nonBlockingWrite in class RandomStreamObject

Throws:

IOException