org.simpleframework.transport

Class TransportCursor

java.lang.Object

org.simpleframework.transport.TransportCursor

All Implemented Interfaces:

ByteCursor

public class TransportCursor
extends Object
implements ByteCursor

The TransportCursor object represents a cursor that can read and buffer data from an underlying transport. If the number of bytes read from the cursor is more than required for the HTTP request then those bytes can be pushed back in to the cursor using the reset method. This will only allow the last read to be reset within the cursor safely.

Author:

Niall Gallagher

See Also:

Transport

Constructor Summary

Constructors

Constructor and Description
TransportCursor(Transport transport) Constructor for the TransportCursor object.
TransportCursor(Transport transport, int size) Constructor for the TransportCursor object.

Method Summary

Modifier and Type	Method and Description
boolean	isOpen() Determines whether the cursor is still open.
boolean	isReady() Determines whether the cursor is ready for reading.
void	push(byte[] data) Pushes the provided data on to the cursor.
void	push(byte[] data, int off, int len) Pushes the provided data on to the cursor.
int	read(byte[] data) Reads a block of bytes from the underlying stream.
int	read(byte[] data, int off, int len) Reads a block of bytes from the underlying stream.
int	ready() Provides the number of bytes that can be read from the stream without blocking.
int	reset(int size) Moves the cursor backward within the stream.

Methods inherited from class java.lang.Object

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

Constructor Detail

TransportCursor

public TransportCursor(Transport transport)

Constructor for the TransportCursor object. This requires a transport to read the bytes from. By default this will create a buffer of of the specified size to read the input in to which enabled bytes to be buffered internally.

Parameters:

transport - this is the underlying transport to use

TransportCursor

public TransportCursor(Transport transport,
                       int size)

Constructor for the TransportCursor object. This requires a transport to read the bytes from. By default this will create a buffer of of the specified size to read the input in to which enabled bytes to be buffered internally.

Parameters:

transport - this is the underlying transport to use

size - this is the size of the internal buffer to use

Method Detail

isOpen

public boolean isOpen()
               throws IOException

Determines whether the cursor is still open. The cursor is considered open if there are still bytes to read. If there is still bytes buffered and the underlying transport is closed then the cursor is still considered open.

Specified by:

isOpen in interface ByteCursor

Returns:

true if there is nothing more to be read from this

Throws:

IOException

isReady

public boolean isReady()
                throws IOException

Determines whether the cursor is ready for reading. When the cursor is ready then it guarantees that some amount of bytes can be read from the underlying stream without blocking.

Specified by:

isReady in interface ByteCursor

Returns:

true if some data can be read without blocking

Throws:

IOException

ready

public int ready()
          throws IOException

Provides the number of bytes that can be read from the stream without blocking. This is typically the number of buffered or available bytes within the stream. When this reaches zero then the cursor may perform a blocking read.

Specified by:

ready in interface ByteCursor

Returns:

the number of bytes that can be read without blocking

Throws:

IOException

read

public int read(byte[] data)
         throws IOException

Reads a block of bytes from the underlying stream. This will read up to the requested number of bytes from the underlying stream. If there are no ready bytes on the stream this can return zero, representing the fact that nothing was read.

Specified by:

read in interface ByteCursor

Parameters:

data - this is the array to read the bytes in to

Returns:

this returns the number of bytes read from the stream

Throws:

IOException

read

public int read(byte[] data,
                int off,
                int len)
         throws IOException

Reads a block of bytes from the underlying stream. This will read up to the requested number of bytes from the underlying stream. If there are no ready bytes on the stream this can return zero, representing the fact that nothing was read.

Specified by:

read in interface ByteCursor

Parameters:

data - this is the array to read the bytes in to

off - this is the offset to begin writing the bytes to

len - this is the number of bytes that are requested

Returns:

this returns the number of bytes read from the stream

Throws:

IOException

push

public void push(byte[] data)
          throws IOException

Pushes the provided data on to the cursor. Data pushed on to the cursor will be the next data read from the cursor. This complements the reset method which will reset the cursors position on a stream. Allowing data to be pushed on to the cursor allows more flexibility.

Specified by:

push in interface ByteCursor

Parameters:

data - this is the data to be pushed on to the cursor

Throws:

IOException

push

public void push(byte[] data,
                 int off,
                 int len)
          throws IOException

Pushes the provided data on to the cursor. Data pushed on to the cursor will be the next data read from the cursor. This complements the reset method which will reset the cursors position on a stream. Allowing data to be pushed on to the cursor allows more flexibility.

Specified by:

push in interface ByteCursor

Parameters:

data - this is the data to be pushed on to the cursor

off - this is the offset to begin reading the bytes

len - this is the number of bytes that are to be used

Throws:

IOException

reset

public int reset(int size)
          throws IOException

Moves the cursor backward within the stream. This ensures that any bytes read from the last read can be pushed back in to the stream so that they can be read again. This will throw an exception if the reset can not be performed.

Specified by:

reset in interface ByteCursor

Parameters:

size - this is the number of bytes to reset back

Returns:

this is the number of bytes that have been reset

Throws:

IOException