edu.rice.cs.util
Class InputStreamRedirector

java.lang.Object
  java.io.InputStream
      edu.rice.cs.util.InputStreamRedirector

All Implemented Interfaces:

java.io.Closeable

public abstract class InputStreamRedirector
extends java.io.InputStream

Redirects requests for input through the abstract method _getInput().

Version:

$Id: InputStreamRedirector.java 5443 2011-08-17 04:58:50Z rcartwright $

Field Summary

protected java.util.ArrayList<java.lang.Character>

_buffer Buffer that stores the current set of bytes.

Constructor Summary

InputStreamRedirector()
Constructs a new InputStreamRedirector.

Method Summary

protected abstract java.lang.String	_getInput() This method gets called whenever input is requested from the stream and nothing is currently available.
private void	_readInputIntoBuffer() Reads a single "line" of input into the buffer, i.e.
int	available()
int	read() Overrides the read() in PipedInputStream so that if the stream is empty, it asks for more input from _getInput().
int	read(byte[] b) Tries to fill b with bytes from the user, prompting for input only if the stream is already empty.
int	read(byte[] b, int off, int len) Tries to fill b with bytes from the user, prompting for input only if the stream is already empty.

Methods inherited from class java.io.InputStream

close, mark, markSupported, reset, skip

Methods inherited from class java.lang.Object

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

Field Detail

_buffer

protected volatile java.util.ArrayList<java.lang.Character> _buffer

Buffer that stores the current set of bytes. TODO: perhaps this should use an array for efficiency This is only used as a char queue.

Constructor Detail

InputStreamRedirector

public InputStreamRedirector()

Constructs a new InputStreamRedirector.

Method Detail

_getInput

protected abstract java.lang.String _getInput()
                                       throws java.io.IOException

This method gets called whenever input is requested from the stream and nothing is currently available. Subclasses should return the appropriate input to feed to the input stream. When using a readLine() method, be sure to append a newline to the end of the input.

Returns:

the input to the stream, empty string to indicate end of stream

Throws:

java.io.IOException

_readInputIntoBuffer

private void _readInputIntoBuffer()
                           throws java.io.IOException

Reads a single "line" of input into the buffer, i.e. makes a single call to _getInput() and puts the result into the buffer.

Throws:

java.io.IOException

read

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

Tries to fill b with bytes from the user, prompting for input only if the stream is already empty.

Overrides:

read in class java.io.InputStream

Parameters:

b - the byte array to fill

Returns:

the number of bytes successfully read

Throws:

java.io.IOException

read

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

Tries to fill b with bytes from the user, prompting for input only if the stream is already empty.

Overrides:

read in class java.io.InputStream

Parameters:

b - the byte array to fill

off - the offset in the byte array

len - the number of characters to try to read

Returns:

the number of bytes successfully read

Throws:

java.io.IOException

read

public int read()
         throws java.io.IOException

Overrides the read() in PipedInputStream so that if the stream is empty, it asks for more input from _getInput().

Specified by:

read in class java.io.InputStream

Returns:

the next character in the stream

Throws:

java.io.IOException - if an I/O exception

available

public int available()

Overrides:

available in class java.io.InputStream

Returns:

the number of characters available in this stream.