printstreamlogtarget.java

来自「JfreeChart 常用图表例子」· Java 代码 · 共 126 行

/* ========================================================================
 * JCommon : a free general purpose class library for the Java(tm) platform
 * ========================================================================
 *
 * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
 * 
 * Project Info:  http://www.jfree.org/jcommon/index.html
 *
 * This library is free software; you can redistribute it and/or modify it 
 * under the terms of the GNU Lesser General Public License as published by 
 * the Free Software Foundation; either version 2.1 of the License, or 
 * (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful, but 
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 
 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License 
 * along with this library; if not, write to the Free Software Foundation, 
 * Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
 *
 * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 
 * in the United States and other countries.]
 * 
 * -------------------------
 * PrintStreamLogTarget.java
 * -------------------------
 * (C)opyright 2003-2005, by Thomas Morgner and Contributors.
 *
 * Original Author:  Thomas Morgner;
 * Contributor(s):   David Gilbert (for Object Refinery Limited);
 *
 * $Id: PrintStreamLogTarget.java,v 1.5 2005/06/01 14:12:30 taqua Exp $
 *
 * Changes 
 * -------
 * 02-Dec-2003 : Initial version
 * 11-Feb-2004 : Added missing Javadocs (DG);
 * 
 */

package org.jfree.util;

import java.io.PrintStream;
import java.io.Serializable;

/**
 * A log target that sends output to a {@link PrintStream}.
 *
 * @author Thomas Morgner
 */
public class PrintStreamLogTarget implements LogTarget, Serializable {

  /** For serialization. */
  private static final long serialVersionUID = 6510564403264504688L;

  /** The printstream we use .. */
  private PrintStream printStream;

  /**
   * The default constructor. Initializes this target with the system.out 
   * stream.
   * <p>
   * All {@link org.jfree.util.LogTarget} implementations need a default 
   * constructor.
   */
  public PrintStreamLogTarget() {
    this (System.out);
  }

  /**
   * The default constructor. Initializes this target with the given stream.
   * <p>
   * @param printStream the print stream that is used to write the content.
   */
  public PrintStreamLogTarget(final PrintStream printStream) {
    if (printStream == null) {
      throw new NullPointerException();
    }
    this.printStream = printStream;
  }

  /**
   * Logs a message to the main log stream. All attached logStreams will also
   * receive this message. If the given log-level is higher than the given 
   * debug-level in the main config file, no logging will be done.
   *
   * @param level log level of the message.
   * @param message text to be logged.
   */
  public void log(int level, final Object message) {
    if (level > 3) {
      level = 3;
    }
    this.printStream.print(LEVELS[level]);
    this.printStream.println(message);
    if (level < 3) {
      System.out.flush();
    }
  }

  /**
   * logs an message to the main-log stream. All attached logStreams will also
   * receive this message. If the given log-level is higher than the given 
   * debug-level in the main config file, no logging will be done.
   *
   * The exception's stacktrace will be appended to the log-stream
   *
   * @param level log level of the message.
   * @param message text to be logged.
   * @param e the exception, which should be logged.
   */
  public void log(int level, final Object message, final Exception e) {
    if (level > 3) {
      level = 3;
    }
    this.printStream.print(LEVELS[level]);
    this.printStream.println(message);
    e.printStackTrace(this.printStream);
    if (level < 3) {
      System.out.flush();
    }
  }
}