org.apache.avalon.fortress.tools
Class ChangedFileOutputStream

java.lang.Object
  java.io.OutputStream
      org.apache.avalon.fortress.tools.ChangedFileOutputStream

All Implemented Interfaces:

java.io.Closeable, java.io.Flushable

public final class ChangedFileOutputStream
extends java.io.OutputStream

OutputStream which will only update an existing file if its contents actually change. Needed to keep Ant from rebuilding jars even when nothing has changed.

Version:

CVS $Revision: 1.1 $ $Date: 2004/04/02 08:29:44 $

Author:

The Avalon Team

Field Summary

private java.io.ByteArrayOutputStream	m_bos The output stream used to buffer data being writen.
private java.io.File	m_file The file to write to.

Constructor Summary

ChangedFileOutputStream(java.io.File file)
Creates a new ChangedFileOutputStream.

Method Summary

void	close() Close the stream.
private byte[]	readBytes(java.io.File file) Reads the full contents of a file into a byte array.
void	write(int b) Writes the specified byte to this output stream.
private void	writeBytes(java.io.File file, byte[] bytes) Reads the full contents of a byte array out to a file.

Methods inherited from class java.io.OutputStream

flush, write, write

Methods inherited from class java.lang.Object

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

Field Detail

m_file

private java.io.File m_file

The file to write to.

m_bos

private java.io.ByteArrayOutputStream m_bos

The output stream used to buffer data being writen.

Constructor Detail

ChangedFileOutputStream

public ChangedFileOutputStream(java.io.File file)

Creates a new ChangedFileOutputStream.

Parameters:

file - The file to write to.

Method Detail

write

public void write(int b)
           throws java.io.IOException

Writes the specified byte to this output stream.

Specified by:

write in class java.io.OutputStream

Parameters:

b - Byte to write.

Throws:

java.io.IOException - If an I/O error occurs.

close

public void close()
           throws java.io.IOException

Close the stream.

Specified by:

close in interface java.io.Closeable

Overrides:

close in class java.io.OutputStream

Throws:

java.io.IOException - If an I/O error occurs.

readBytes

private byte[] readBytes(java.io.File file)
                  throws java.io.IOException

Reads the full contents of a file into a byte array. The file contents are treated as binary data.

Parameters:

file - File to read.

Returns:

The contents of the file as a byte array.

Throws:

java.io.IOException - If the file could not be read for any reason.

writeBytes

private void writeBytes(java.io.File file,
                        byte[] bytes)
                 throws java.io.IOException

Reads the full contents of a byte array out to a file.

Parameters:

file - File to write to.

bytes - The binary data to write.

Throws:

java.io.IOException - If the file could not be written to for any reason.