alvinalexander.com | career | drupal | java | mac | mysql | perl | scala | uml | unix  

What this is

This file is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Other links

The source code

/*
 * Copyright (C) The Apache Software Foundation. All rights reserved.
 *
 * This software is published under the terms of the Apache Software
 * License version 1.1, a copy of which has been included with this
 * distribution in the LICENSE.APL file.
 */


import java.io.*;
import org.apache.log4j.*;


/**
 * An OutputStream that flushes out to a Category.

* * Note that no data is written out to the Category until the stream is * flushed or closed.

* * Example:

 * // make sure everything sent to System.err is logged
 * System.setErr(new PrintStream(new LoggingOutputStream(Category.getRoot(), Priority.WARN), true));
 * 
 * // make sure everything sent to System.out is also logged
 * System.setOut(new PrintStream(new LoggingOutputStream(Category.getRoot(), Priority.INFO), true));
 * 
* * @author Jim Moore * @see Category */ public class LoggingOutputStream extends OutputStream { protected static final String LINE_SEPERATOR = System.getProperty("line.separator"); /** * Used to maintain the contract of {@link #close()}. */ protected boolean hasBeenClosed = false; /** * The internal buffer where data is stored. */ protected byte[] buf; /** * The number of valid bytes in the buffer. This value is always * in the range 0 through buf.length; elements * buf[0] through buf[count-1] contain valid * byte data. */ protected int count; /** * Remembers the size of the buffer for speed. */ private int bufLength; /** * The default number of bytes in the buffer. =2048 */ public static final int DEFAULT_BUFFER_LENGTH = 2048; /** * The category to write to. */ protected Category category; /** * The priority to use when writing to the Category. */ protected Priority priority; private LoggingOutputStream() { // illegal } /** * Creates the LoggingOutputStream to flush to the given Category. * * @param cat the Category to write to * * @param priority the Priority to use when writing to the Category * * @exception IllegalArgumentException * if cat == null or priority == null */ public LoggingOutputStream(Category cat, Priority priority) throws IllegalArgumentException { if (cat == null) { throw new IllegalArgumentException("cat == null"); } if (priority == null) { throw new IllegalArgumentException("priority == null"); } this.priority = priority; category = cat; bufLength = DEFAULT_BUFFER_LENGTH; buf = new byte[DEFAULT_BUFFER_LENGTH]; count = 0; } /** * Closes this output stream and releases any system resources * associated with this stream. The general contract of close * is that it closes the output stream. A closed stream cannot perform * output operations and cannot be reopened. */ public void close() { flush(); hasBeenClosed = true; } /** * Writes the specified byte to this output stream. The general * contract for write is that one byte is written * to the output stream. The byte to be written is the eight * low-order bits of the argument b. The 24 * high-order bits of b are ignored. * * @param b the byte to write * * @exception IOException * if an I/O error occurs. In particular, * an IOException may be thrown if the * output stream has been closed. */ public void write(final int b) throws IOException { if (hasBeenClosed) { throw new IOException("The stream has been closed."); } // don't log nulls if (b == 0) { return; } // would this be writing past the buffer? if (count == bufLength) { // grow the buffer final int newBufLength = bufLength+DEFAULT_BUFFER_LENGTH; final byte[] newBuf = new byte[newBufLength]; System.arraycopy(buf, 0, newBuf, 0, bufLength); buf = newBuf; bufLength = newBufLength; } buf[count] = (byte)b; count++; } /** * Flushes this output stream and forces any buffered output bytes * to be written out. The general contract of flush is * that calling it is an indication that, if any bytes previously * written have been buffered by the implementation of the output * stream, such bytes should immediately be written to their * intended destination. */ public void flush() { if (count == 0) { return; } // don't print out blank lines; flushing from PrintStream puts out these if (count == LINE_SEPERATOR.length()) { if ( ((char)buf[0]) == LINE_SEPERATOR.charAt(0) && ( ( count == 1 ) || // <- Unix & Mac, -> Windows ( (count == 2) && ((char)buf[1]) == LINE_SEPERATOR.charAt(1) ) ) ) { reset(); return; } } final byte[] theBytes = new byte[count]; System.arraycopy(buf, 0, theBytes, 0, count); category.log(priority, new String(theBytes)); reset(); } private void reset() { // not resetting the buffer -- assuming that if it grew that it // will likely grow similarly again count = 0; } }
... this post is sponsored by my books ...

#1 New Release!

FP Best Seller

 

new blog posts

 

Copyright 1998-2021 Alvin Alexander, alvinalexander.com
All Rights Reserved.

A percentage of advertising revenue from
pages under the /java/jwarehouse URI on this website is
paid back to open source projects.