org.python.util

Class ConsoleOutputStream

java.lang.Object

java.io.OutputStream

java.io.FilterOutputStream

org.python.util.ConsoleOutputStream

All Implemented Interfaces:

Closeable, Flushable, AutoCloseable

public class ConsoleOutputStream
extends FilterOutputStream

This class may be used to wrap and replace System.out so that the console handling library (JLine or Java Readline) can treat an incomplete line (one without a newline) as a prompt string, and so know the true position of the cursor. It achieves this by keeping a copy of bytes that pass through from from upstream to the true System.out, until either a newline arrives, or a defined capacity (typically the console width) is reached. If client code requests the partial line as a prompt, that action also empties the buffer. In that case, the client (which is the console object) is responsible for making the prompt emerge on the real console.

Constructor Summary

Constructors

Constructor and Description
ConsoleOutputStream(OutputStream out, int promptCapacity) Create a wrapper on an OutputStream that holds a copy of the last incomplete line written to it (as bytes), in case it is needed as a console prompt.

Method Summary

Modifier and Type	Method and Description
void	close()
void	flush()
void	write(int b) This write method steals a copy of each byte in a buffer while passing it on to the wrapped stream.

Methods inherited from class java.io.FilterOutputStream

write, write

Methods inherited from class java.lang.Object

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

Constructor Detail

ConsoleOutputStream

public ConsoleOutputStream(OutputStream out,
                           int promptCapacity)

Create a wrapper on an OutputStream that holds a copy of the last incomplete line written to it (as bytes), in case it is needed as a console prompt.

Parameters:

out - the stream wrapped (normally System.out)

promptCapacity - maximum number of bytes to buffer

Method Detail

write

public void write(int b)
           throws IOException

This write method steals a copy of each byte in a buffer while passing it on to the wrapped stream. The buffer is reset by each newline, when it overflows, or by the client when it is taken as a console prompt in getPrompt(Charset).

Overrides:

write in class FilterOutputStream

Throws:

IOException

flush

public void flush()
           throws IOException

Specified by:

flush in interface Flushable

Overrides:

flush in class FilterOutputStream

Throws:

IOException

close

public void close()
           throws IOException

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Overrides:

close in class FilterOutputStream

Throws:

IOException