Quadcap Embeddable Server

com/quadcap/io/LogReader.java

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package com.quadcap.io;

/* Copyright 1997 - 2003 Quadcap Software.  All rights reserved.
 *
 * This software is distributed under the Quadcap Free Software License.
 * This software may be used or modified for any purpose, personal or
 * commercial.  Open Source redistributions are permitted.  Commercial
 * redistribution of larger works derived from, or works which bundle
 * this software requires a "Commercial Redistribution License"; see
 * http://www.quadcap.com/purchase.
 *
 * Redistributions qualify as "Open Source" under  one of the following terms:
 *   
 *    Redistributions are made at no charge beyond the reasonable cost of
 *    materials and delivery.
 *
 *    Redistributions are accompanied by a copy of the Source Code or by an
 *    irrevocable offer to provide a copy of the Source Code for up to three
 *    years at the cost of materials and delivery.  Such redistributions
 *    must allow further use, modification, and redistribution of the Source
 *    Code under substantially the same terms as this license.
 *
 * Redistributions of source code must retain the copyright notices as they
 * appear in each source code file, these license terms, and the
 * disclaimer/limitation of liability set forth as paragraph 6 below.
 *
 * Redistributions in binary form must reproduce this Copyright Notice,
 * these license terms, and the disclaimer/limitation of liability set
 * forth as paragraph 6 below, in the documentation and/or other materials
 * provided with the distribution.
 *
 * The Software is provided on an "AS IS" basis.  No warranty is
 * provided that the Software is free of defects, or fit for a
 * particular purpose.  
 *
 * Limitation of Liability. Quadcap Software shall not be liable
 * for any damages suffered by the Licensee or any third party resulting
 * from use of the Software.
 */

import java.io.IOException;
import java.io.Reader;
import java.io.Writer;

import com.quadcap.util.Debug;
import com.quadcap.util.Util;

/**
 * A filter input stream that tees off input into a log file, with a prefix
 * identifying the stream.
 *
 * @author Stan Bailes
 */

public class LogReader extends Reader {
    Reader              in;
    Writer              log;
    String              prefix;
    boolean             bol = true;
    
    /**
     * Construct a new log reader
     *
     * @param is the underlying reader
     * @param log the log stream
     * @param prefix a string identifying this log stream to be prefixed
     *          to every line output by this filter.
     */
    public LogReader(Reader in, Writer log, String prefix) {
        this.in = in;
        this.log = log;
        this.prefix = prefix;
    }

    /**
     * Read (and log) a byte
     *
     * @exception IOException may be thrown
     */
    synchronized public int read() throws IOException {
        int c = in.read();
        if (c > 0) {
            if (bol) log.write(prefix);
            log.write((char)c);
        }
        bol = (c == '\n');
        return c;
    }

    /**
     * Read (and log) an array of bytes
     */
    public int read(char[] cbuf, int off, int len) throws IOException {
        for (int i = 0; i < len; i++) {
            int c = read();
            if (c < 0) return i > 0 ? i : -1;
            cbuf[off + i] = (char)c;
        }
        return len > 0 ? len : -1;
    }

    /**
     * Close the underlying stream (but not the log stream!)
     *
     * @exception IOException may be thrown
     */
    public void close() throws IOException {
        in.close();
    }
}