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:

Closeable, AutoCloseable

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

Fields

Modifier and Type	Field	Description
private final ConnectionChild	conChild	ConnectionChild to get synchronizion object
private long	pos
private final PositionedStoreStream	positionedStream

Fields inherited from class FilterInputStream

in

Constructor Summary

Constructors

Constructor	Description
AutoPositioningStream(ConnectionChild conChild, InputStream in, Object parent)	Constructs AutoPositioningStream object.

Method Summary

Modifier and Type	Method	Description
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 BinaryToRawStream

getLength

Methods inherited from class FilterInputStream

available, close, mark, markSupported, reset

Methods inherited from class InputStream

nullInputStream, readAllBytes, readNBytes, readNBytes, skipNBytes, transferTo

Methods inherited from class Object

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

Field Details

conChild

private final ConnectionChild conChild

ConnectionChild to get synchronizion object

pos

private long pos

positionedStream

private final PositionedStoreStream positionedStream

Constructor Details

AutoPositioningStream

AutoPositioningStream(ConnectionChild conChild,
 InputStream in,
 Object parent)
               throws 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:

IOException - if an I/O error occurs

Method Details

read

public int read()
         throws IOException

Reads a single byte from the underlying stream.

Overrides:

read in class FilterInputStream

Returns:

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

Throws:

IOException - if an I/O error occurs

read

public int read(byte[] b,
 int off,
 int len)
         throws 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 FilterInputStream

Returns:

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

Throws:

IOException - if an I/O error occurs

skip

public long skip(long n)
          throws IOException

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

Overrides:

skip in class FilterInputStream

Returns:

The actual number of bytes skipped.

Throws:

IOException - if an I/O error occurs

read

public int read(byte[] b)
         throws IOException

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

Overrides:

read in class FilterInputStream

Returns:

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

Throws:

IOException - if an I/O error occurs

setPosition

private void setPosition()
                  throws IOException

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

Throws:

IOException