org.jline.utils

Class NonBlockingReader

java.lang.Object

java.io.Reader

org.jline.utils.NonBlockingReader

All Implemented Interfaces:

Closeable, AutoCloseable, Readable, Runnable

public class NonBlockingReader
extends Reader
implements Runnable

This class wraps a regular reader and allows it to appear as if it is non-blocking; that is, reads can be performed against it that timeout if no data is seen for a period of time. This effect is achieved by having a separate thread perform all non-blocking read requests and then waiting on the thread to complete.

VERY IMPORTANT NOTES

• This class is not thread safe. It expects at most one reader.
• The shutdown() method must be called in order to shut down the thread that handles blocking I/O.

Since:

2.7

Author:

Scott C. Gray

Field Summary

Fields

Modifier and Type	Field and Description
static int	READ_EXPIRED

Fields inherited from class java.io.Reader

lock

Constructor Summary

Constructors

Constructor and Description
NonBlockingReader(String name, Reader in) Creates a NonBlockingReader out of a normal blocking reader.

Method Summary

Modifier and Type	Method and Description
void	clear()
void	close()
int	peek(long timeout) Peeks to see if there is a byte waiting in the input stream without actually consuming the byte.
int	read()
int	read(char[] b, int off, int len) This version of read() is very specific to jline's purposes, it will always always return a single byte at a time, rather than filling the entire buffer.
int	read(long timeout) Attempts to read a character from the input stream for a specific period of time.
boolean	ready()
void	run()
void	shutdown() Shuts down the thread that is handling blocking I/O.

Methods inherited from class java.io.Reader

mark, markSupported, read, read, reset, skip

Methods inherited from class java.lang.Object

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

Field Detail

READ_EXPIRED

public static final int READ_EXPIRED

See Also:

Constant Field Values

Constructor Detail

NonBlockingReader

public NonBlockingReader(String name,
                         Reader in)

Creates a NonBlockingReader out of a normal blocking reader. Note that this call also spawn a separate thread to perform the blocking I/O on behalf of the thread that is using this class. The shutdown() method must be called in order to shut this thread down.

Parameters:

in - The reader to wrap

Method Detail

shutdown

public void shutdown()

Shuts down the thread that is handling blocking I/O. Note that if the thread is currently blocked waiting for I/O it will not actually shut down until the I/O is received.

close

public void close()
           throws IOException

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Specified by:

close in class Reader

Throws:

IOException

read

public int read()
         throws IOException

Overrides:

read in class Reader

Throws:

IOException

peek

public int peek(long timeout)
         throws IOException

Peeks to see if there is a byte waiting in the input stream without actually consuming the byte.

Parameters:

timeout - The amount of time to wait, 0 == forever

Returns:

-1 on eof, -2 if the timeout expired with no available input or the character that was read (without consuming it).

Throws:

IOException

read

public int read(long timeout)
         throws IOException

Attempts to read a character from the input stream for a specific period of time.

Parameters:

timeout - The amount of time to wait for the character

Returns:

The character read, -1 if EOF is reached, or -2 if the read timed out.

Throws:

IOException

ready

public boolean ready()
              throws IOException

Overrides:

ready in class Reader

Throws:

IOException

read

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

This version of read() is very specific to jline's purposes, it will always always return a single byte at a time, rather than filling the entire buffer.

Specified by:

read in class Reader

Throws:

IOException

run

public void run()

Specified by:

run in interface Runnable

clear

public void clear()
           throws IOException

Throws:

IOException