org.python.util

Class ConsoleInputStream

java.lang.Object

java.io.InputStream

java.io.FilterInputStream

org.python.util.ConsoleInputStream

All Implemented Interfaces:

Closeable, AutoCloseable

public abstract class ConsoleInputStream
extends FilterInputStream

This class is intended to replace System.in for use with console libraries that provide a line-oriented input mechanism. The console libraries provide a method to get the next line from the console as a String. Particular sub-classes should wrap this character-oriented method in a definition of getLine().

The libraries JLine and Java Readline have both been used to give Jython line-recall, editing and a line history preserved between sessions. Both deal with the console encoding internally, and interact with the user in terms of a buffer of characters. Our need in Jython is to access a byte-stream encoding the characters, with line-endings, since it is the text layer of the Python io stack, whether we are using the io module or file built-in, that should deal with encoding.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	ConsoleInputStream.EOLPolicy Enumeration used to specify whether an end-of-line should be added or replaced at the end of each line read.

Method Summary

Methods

Modifier and Type	Method and Description
int	available() The number of bytes left unread in the current encoded line.
void	mark(int readlimit) Mark is not supported.
boolean	markSupported() Mark is not supported.
int	read() Read the next byte of data from the buffered input line.
int	read(byte[] b, int off, int len) Reads up to len bytes of data from this input stream into an array of bytes.
void	reset() Mark is not supported.
long	skip(long n) Skip forward n bytes within the current encoded line.

Methods inherited from class java.io.FilterInputStream

close, read

Methods inherited from class java.lang.Object

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

Method Detail

read

public int read()
         throws IOException

Read the next byte of data from the buffered input line. The byte is returned as an int in the range 0 to 255. If no byte is available because the end of the stream has been recognised, the value -1 is returned. This method blocks until input data are available, the end of the stream is detected, or an exception is thrown. Normally, an empty line results in an encoded end-of-line being returned.

Overrides:

read in class FilterInputStream

Throws:

IOException

read

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

Reads up to len bytes of data from this input stream into an array of bytes. If len is not zero, the method blocks until some input is available; otherwise, no bytes are read and 0 is returned. This implementation calls getLine() at most once to get a line of characters from the console, and encodes them as bytes to be read back from the stream.

Overrides:

read in class FilterInputStream

Throws:

IOException

EOFException

skip

public long skip(long n)
          throws IOException

Skip forward n bytes within the current encoded line. A call to skip will not result in reading a new line with getLine().

Overrides:

skip in class FilterInputStream

Throws:

IOException

available

public int available()
              throws IOException

The number of bytes left unread in the current encoded line.

Overrides:

available in class FilterInputStream

Throws:

IOException

mark

public void mark(int readlimit)

Mark is not supported.

Overrides:

mark in class FilterInputStream

reset

public void reset()
           throws IOException

Mark is not supported.

Overrides:

reset in class FilterInputStream

Throws:

IOException

markSupported

public boolean markSupported()

Mark is not supported.

Overrides:

markSupported in class FilterInputStream