org.apache.derby.impl.jdbc
Class AutoPositioningStream

java.lang.Object
  java.io.InputStream
      java.io.FilterInputStream
          org.apache.derby.impl.jdbc.BinaryToRawStream
              org.apache.derby.impl.jdbc.AutoPositioningStream

All Implemented Interfaces:

java.io.Closeable

final class AutoPositioningStream
extends BinaryToRawStream

This Stream is a wrapper for PositionedStoreStream to set the position correctly before performing any operation on it. All the read and skip methods ensure that the PositionedStoreStream is set to right position before actually performing these operations. PositionedStoreStream is accessed within synchronized block to ensure exclusive access to it. This class must be constructed while synchronizing on ConnectionChild.getConnectionSynchronization

Field Summary

private ConnectionChild	conChild ConnectionChild to get synchronizion object
private long	pos
private PositionedStoreStream	positionedStream

Fields inherited from class java.io.FilterInputStream

in

Constructor Summary

AutoPositioningStream(ConnectionChild conChild, java.io.InputStream in, java.lang.Object parent)
Constructs AutoPositioningStream object.

Method Summary

int	read() Reads a single byte from the underlying stream.
int	read(byte[] b) Reads a number of bytes from the underlying stream and stores them in the specified byte array.
int	read(byte[] b, int off, int len) Reads a number of bytes from the underlying stream and stores them in the specified byte array at the specified offset.
private void	setPosition() Checks if positionedStream's position was changed since last used, sets the position to right position if its changed.
long	skip(long n) Skips up to the specified number of bytes from the underlying stream.

Methods inherited from class org.apache.derby.impl.jdbc.BinaryToRawStream

getLength

Methods inherited from class java.io.FilterInputStream

available, close, mark, markSupported, reset

Methods inherited from class java.lang.Object

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

Field Detail

conChild

private final ConnectionChild conChild

ConnectionChild to get synchronizion object

pos

private long pos

positionedStream

private final PositionedStoreStream positionedStream

Constructor Detail

AutoPositioningStream

AutoPositioningStream(ConnectionChild conChild,
                      java.io.InputStream in,
                      java.lang.Object parent)
                throws java.io.IOException

Constructs AutoPositioningStream object. This constructor must be called from block synchronized on conChild.getConnectionSynchronization.

Parameters:

conChild - ConnectionChild to get synchronization object before accessing PositionedStoreStream

in - InputStream

parent - Parent of the stream to prevent it from being gc.

Throws:

java.io.IOException - if an I/O error occurs

Method Detail

read

public int read()
         throws java.io.IOException

Reads a single byte from the underlying stream.

Overrides:

read in class java.io.FilterInputStream

Returns:

The next byte of data, or -1 if the end of the stream is reached.

Throws:

java.io.IOException - if an I/O error occurs

read

public int read(byte[] b,
                int off,
                int len)
         throws java.io.IOException

Reads a number of bytes from the underlying stream and stores them in the specified byte array at the specified offset.

Overrides:

read in class java.io.FilterInputStream

Returns:

The actual number of bytes read, or -1 if the end of the stream is reached.

Throws:

java.io.IOException - if an I/O error occurs

skip

public long skip(long n)
          throws java.io.IOException

Skips up to the specified number of bytes from the underlying stream.

Overrides:

skip in class java.io.FilterInputStream

Returns:

The actual number of bytes skipped.

Throws:

java.io.IOException - if an I/O error occurs

read

public int read(byte[] b)
         throws java.io.IOException

Reads a number of bytes from the underlying stream and stores them in the specified byte array.

Overrides:

read in class java.io.FilterInputStream

Returns:

The actual number of bytes read, or -1 if the end of the stream is reached.

Throws:

java.io.IOException - if an I/O error occurs

setPosition

private void setPosition()
                  throws java.io.IOException

Checks if positionedStream's position was changed since last used, sets the position to right position if its changed.

Throws:

java.io.IOException