xtc.util
Class NestedReader

java.lang.Object
  java.io.Reader
      xtc.util.NestedReader

All Implemented Interfaces:

java.io.Closeable, java.lang.Readable

public class NestedReader
extends java.io.Reader

Implementation of a nested reader. A nested reader combines several streams into a single stream. It starts by reading from a main stream. Additional streams are added through the insert(Reader) and insert(Reader,NestedReader.EOFListener) methods and are consumed completely before returning to read from the previous stream. Note that inserted streams are automatically closed after having being consumed. Further note that closing a nested reader closes all streams currently associated with that nested reader.

Version:

$Revision: 1.5 $

Author:

Robert Grimm

Nested Class Summary

static interface

NestedReader.EOFListener Event listener to provide notification a stream has reached its end.

Field Summary

protected boolean	closed Flag for whether this nested reader has been closed.
protected NestedReader.EOFListener	listener The corresponding end-of-file listener.
protected java.util.LinkedList<NestedReader.EOFListener>	listenerStack The stack of listeners, with the most recently added listener at the front.
protected java.io.Reader	reader The current character stream.
protected java.util.LinkedList<java.io.Reader>	readerStack The stack of readers, with the most recently added stream at the front.

Fields inherited from class java.io.Reader

lock

Constructor Summary

NestedReader(java.io.Reader in)
Create a new nested reader.

Method Summary

void	close()
void	insert(java.io.Reader in) Insert the specified character stream.
void	insert(java.io.Reader in, NestedReader.EOFListener eof) Insert the specified character stream.
java.io.Reader	open(java.lang.String file) Open the specified file.
int	read()
int	read(char[] cbuf, int off, int len)

Methods inherited from class java.io.Reader

mark, markSupported, read, read, ready, reset, skip

Methods inherited from class java.lang.Object

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

Field Detail

closed

protected boolean closed

Flag for whether this nested reader has been closed.

reader

protected java.io.Reader reader

The current character stream.

listener

protected NestedReader.EOFListener listener

The corresponding end-of-file listener.

readerStack

protected java.util.LinkedList<java.io.Reader> readerStack

The stack of readers, with the most recently added stream at the front.

listenerStack

protected java.util.LinkedList<NestedReader.EOFListener> listenerStack

The stack of listeners, with the most recently added listener at the front.

Constructor Detail

NestedReader

public NestedReader(java.io.Reader in)

Create a new nested reader.

Parameters:

in - The main stream.

Method Detail

open

public java.io.Reader open(java.lang.String file)
                    throws java.io.IOException

Open the specified file. The implementation of this method simply creates a new file reader with the specified file name.

Parameters:

file - The file name.

Returns:

The corresponding character stream.

Throws:

java.io.IOException - Signals an I/O error.

insert

public void insert(java.io.Reader in)
            throws java.io.IOException

Insert the specified character stream. After reading all characters from the specified stream, this nested reader silently returns to reading characters from the current stream.

Parameters:

in - The stream.

Throws:

java.io.IOException - Signals an I/O error.

insert

public void insert(java.io.Reader in,
                   NestedReader.EOFListener eof)
            throws java.io.IOException

Insert the specified character stream. After reading all characters from the specified stream, but before returning to read characters from the current stream, this nested reader notifies the specified listener.

Parameters:

in - The stream.

eof - The listener to be notified when the specified stream has been consumed.

Throws:

java.io.IOException - Signals an I/O error.

read

public int read()
         throws java.io.IOException

Overrides:

read in class java.io.Reader

Throws:

java.io.IOException

read

public int read(char[] cbuf,
                int off,
                int len)
         throws java.io.IOException

Specified by:

read in class java.io.Reader

Throws:

java.io.IOException

close

public void close()
           throws java.io.IOException

Specified by:

close in interface java.io.Closeable

Specified by:

close in class java.io.Reader

Throws:

java.io.IOException