ikrs.io
Class ReplacingInputStream

java.lang.Object
  java.io.InputStream
      ikrs.io.ReplacingInputStream

All Implemented Interfaces:

java.io.Closeable

public class ReplacingInputStream
extends java.io.InputStream

The ReplacingInputStream is an InputStream implementation that allows to specify a byte sequence replacement map which will be applied directly on processing the underlying stream. Imagine you want to read a large text file and want to replace some tokens. Usually you would convert the file contents - a byte sequence - into a String and then call the replace/replaceAll method. If there are n tokens to be replaced you would have to call replace n times. Instead the ReplacingInputStream matches the given byte patterns directly while the bytes are read. It uses a MultiStopMarkInputStream to locate the desired tokens. Example (pseudo code): byte[] data = "This %patternA% a %patternB%.".getBytes(); Map replacementMap = { ( "%patternA%".getBytes() => "is".getBytes() ), ( "$patternB%".getbytes() => "test".getBytes() ) }; InputStream in = new ReplacingInputStream( data, replacementMap ); Reading from the stream will then result in the bytes representing: "This is a test."

Constructor Summary

ReplacingInputStream(java.io.InputStream in, java.util.Map<byte[],byte[]> replacementMap)
Create a new ReplacingInputStream.

Method Summary

int	available()
void	close()
boolean	isClosed() Determines if this input stream was closed.
static void	main(java.lang.String[] argv)
int	read()

Methods inherited from class java.io.InputStream

mark, markSupported, read, read, reset, skip

Methods inherited from class java.lang.Object

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

Constructor Detail

ReplacingInputStream

public ReplacingInputStream(java.io.InputStream in,
                            java.util.Map<byte[],byte[]> replacementMap)
                     throws java.lang.NullPointerException

Create a new ReplacingInputStream. Note A: the passed replacement map will not be copied. Concurrent modifications might lead to thread collisions. Note B: the key tokens will be replaced in the order they appear in the map when using an iterator from the entry set.

Parameters:

in - The underlying input stream, must not be null.

replacementMap - The key token / replacement token map.

Throws:

java.lang.NullPointerException - If the passed input stream is null or the replacement map is null or contains any null entries.

Method Detail

read

public int read()
         throws java.io.IOException

Specified by:

read in class java.io.InputStream

Throws:

java.io.IOException

available

public int available()
              throws java.io.IOException

Overrides:

available in class java.io.InputStream

Throws:

java.io.IOException

close

public void close()
           throws java.io.IOException

Specified by:

close in interface java.io.Closeable

Overrides:

close in class java.io.InputStream

Throws:

java.io.IOException

isClosed

public boolean isClosed()

Determines if this input stream was closed.

Returns:

true If the close() method was already called.

main

public static void main(java.lang.String[] argv)