org.jppf.io
Class ChannelInputSource

java.lang.Object
  org.jppf.io.ChannelInputSource

All Implemented Interfaces:

Closeable, InputSource, IO

Direct Known Subclasses:

FileInputSource

public class ChannelInputSource
extends Object
implements InputSource

Input source backed by a ReadableByteChannel.

Author:

Laurent Cohen

Field Summary

protected ReadableByteChannel

channel The backing ReadableByteChannel.

Constructor Summary

ChannelInputSource(ReadableByteChannel channel)
Initialize this input source with the specified SocketWrapper.

Method Summary

void	close() This method does nothing.
int	read(byte[] data, int offset, int len) Read data from this input source into an array of bytes.
int	read(ByteBuffer data) Read data from this input source into a byte buffer.
int	readInt() Read an int value from this input source.
int	skip(int n) Skip n bytes of data form this input source.

Methods inherited from class java.lang.Object

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

Field Detail

channel

protected ReadableByteChannel channel

The backing ReadableByteChannel.

Constructor Detail

ChannelInputSource

public ChannelInputSource(ReadableByteChannel channel)

Initialize this input source with the specified SocketWrapper.

Parameters:

channel - the backing SocketWrapper.

Method Detail

read

public int read(byte[] data,
                int offset,
                int len)
         throws Exception

Read data from this input source into an array of bytes.

Specified by:

read in interface InputSource

Parameters:

data - the buffer into which to write.

offset - the position in the buffer where to start storing the data.

len - the size in bytes of the data to read.

Returns:

the number of bytes actually read, or -1 if end of stream was reached.

Throws:

Exception - if an IO error occurs.

See Also:

InputSource.read(byte[], int, int)

read

public int read(ByteBuffer data)
         throws Exception

Read data from this input source into a byte buffer.

Implementation details:
We read the data by small chunks of max StreamConstants.TEMP_BUFFER_SIZE bytes wrapped in a direct ByteBuffer, to work around the fact that Sun NIO implementation of SocketChannelImpl.read() attempts to allocate a direct buffer of the requested data size (i.e. data.remaining() in our case), if the destination ByteBuffer is not direct.
This implementation can result in a "OutOfMemoryError: Direct buffer space" when the size of the data to read is too large.
See Sun Bug ID: 4879883 for details.

Specified by:

read in interface InputSource

Parameters:

data - the buffer into which to write.

Returns:

the number of bytes actually read, or -1 if end of stream was reached.

Throws:

Exception - if an IO error occurs.

See Also:

InputSource.read(java.nio.ByteBuffer)

readInt

public int readInt()
            throws Exception

Read an int value from this input source.

Specified by:

readInt in interface InputSource

Returns:

the value read, or -1 if an end of file condition was reached.

Throws:

Exception - if an IO error occurs.

See Also:

InputSource.readInt()

skip

public int skip(int n)
         throws Exception

Skip n bytes of data form this input source.

Specified by:

skip in interface InputSource

Parameters:

n - the number of bytes to skip.

Returns:

the number of bytes actually skipped.

Throws:

Exception - if an IO error occurs.

See Also:

InputSource.skip(int)

close

public void close()
           throws IOException

This method does nothing.

Specified by:

close in interface Closeable

Throws:

IOException - if an IO error occurs.

See Also:

Closeable.close()