SafeModeFileAppender.java

/**
 * Logback: the reliable, generic, fast and flexible logging framework.
 * Copyright (C) 1999-2013, QOS.ch. All rights reserved.
 *
 * This program and the accompanying materials are dual-licensed under
 * either the terms of the Eclipse Public License v1.0 as published by
 * the Eclipse Foundation
 *
 *   or (per the licensee's choosing)
 *
 * under the terms of the GNU Lesser General Public License version 2.1
 * as published by the Free Software Foundation.
 */
package ch.qos.logback.classic.multiJVM;

import org.slf4j.Logger;

import ch.qos.logback.classic.LoggerContext;
import ch.qos.logback.classic.encoder.PatternLayoutEncoder;
import ch.qos.logback.classic.spi.ILoggingEvent;
import ch.qos.logback.core.FileAppender;

/**
 * An application to write to a file using a FileAppender in safe mode.
 * 
 * @author Ceki Gulcu
 * 
 */
public class SafeModeFileAppender {

  static long LEN;
  static String FILENAME;
  static String STAMP;

  static public void main(String[] argv) throws Exception {
    if (argv.length != 3) {
      usage("Wrong number of arguments.");
    }

    STAMP = argv[0];
    LEN = Integer.parseInt(argv[1]);
    FILENAME = argv[2];
    writeContinously(STAMP, FILENAME, true);
  }

  static void usage(String msg) {
    System.err.println(msg);
    System.err.println("Usage: java " + SafeModeFileAppender.class.getName()
        + " stamp runLength filename\n" + " stamp JVM instance stamp\n"
        + "   runLength (integer) the number of logs to generate perthread"
        + "    filename (string) the filename where to write\n");
    System.exit(1);
  }

  static LoggerContext buildLoggerContext(String stamp, String filename,
      boolean safetyMode) {
    LoggerContext loggerContext = new LoggerContext();

    FileAppender<ILoggingEvent> fa = new FileAppender<ILoggingEvent>();

    PatternLayoutEncoder patternLayout = new PatternLayoutEncoder();
    patternLayout.setPattern(stamp + " %5p - %m%n");
    patternLayout.setContext(loggerContext);
    patternLayout.start();

    fa.setEncoder(patternLayout);
    fa.setFile(filename);
    fa.setAppend(true);
    fa.setPrudent(safetyMode);
    fa.setContext(loggerContext);
    fa.start();

    ch.qos.logback.classic.Logger root = loggerContext
        .getLogger(Logger.ROOT_LOGGER_NAME);
    root.addAppender(fa);

    return loggerContext;
  }

  static void writeContinously(String stamp, String filename, boolean safetyMode)
      throws Exception {
    LoggerContext lc = buildLoggerContext(stamp, filename, safetyMode);
    Logger logger = lc.getLogger(SafeModeFileAppender.class);

    long before = System.nanoTime();
    for (int i = 0; i < LEN; i++) {
      logger.debug(LoggingThread.msgLong + " " + i);
    }
    lc.stop();
    double durationPerLog = (System.nanoTime() - before) / (LEN * 1000.0);

    System.out.println("Average duration of " + (durationPerLog)
        + " microseconds per log. Safety mode " + safetyMode);
    System.out.println("------------------------------------------------");
  }
}