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The source code

/*
 * Log.java - A class for logging events
 * :tabSize=8:indentSize=8:noTabs=false:
 * :folding=explicit:collapseFolds=1:
 *
 * Copyright (C) 1999, 2003 Slava Pestov
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */

package org.gjt.sp.util;

import java.io.*;
import java.util.*;
import javax.swing.*;
import javax.swing.event.*;

/**
 * This class provides methods for logging events. In terms of functionality,
 * it is somewhere in between System.out.println() and
 * full-blown logging packages such as log4j.

* * All events are logged to an in-memory buffer and optionally a stream, * and those with a high urgency (warnings and errors) are also printed * to standard output.

* * Logging of exception tracebacks is supported.

* * This class can also optionally redirect standard output and error to the log. * * @author Slava Pestov * @version $Id: Log.java,v 1.14 2004/03/28 00:07:27 spestov Exp $ */ public class Log { //{{{ Constants /** * The maximum number of log messages that will be kept in memory. * @since jEdit 2.6pre5 */ public static final int MAXLINES = 500; /** * Debugging message urgency. Should be used for messages only * useful when debugging a problem. * @since jEdit 2.2pre2 */ public static final int DEBUG = 1; /** * Message urgency. Should be used for messages which give more * detail than notices. * @since jEdit 2.2pre2 */ public static final int MESSAGE = 3; /** * Notice urgency. Should be used for messages that directly * affect the user. * @since jEdit 2.2pre2 */ public static final int NOTICE = 5; /** * Warning urgency. Should be used for messages that warrant * attention. * @since jEdit 2.2pre2 */ public static final int WARNING = 7; /** * Error urgency. Should be used for messages that signal a * failure. * @since jEdit 2.2pre2 */ public static final int ERROR = 9; //}}} //{{{ init() method /** * Initializes the log. * @param stdio If true, standard output and error will be * sent to the log * @param level Messages with this log level or higher will * be printed to the system console * @since jEdit 3.2pre4 */ public static void init(boolean stdio, int level) { if(stdio) { if(System.out == realOut && System.err == realErr) { System.setOut(createPrintStream(NOTICE,null)); System.setErr(createPrintStream(ERROR,null)); } } Log.level = level; // Log some stuff log(MESSAGE,Log.class,"When reporting bugs, please" + " include the following information:"); String[] props = { "java.version", "java.vm.version", "java.runtime.version", "java.vendor", "java.compiler", "os.name", "os.version", "os.arch", "user.home", "java.home", "java.class.path", }; for(int i = 0; i < props.length; i++) { log(MESSAGE,Log.class, props[i] + "=" + System.getProperty(props[i])); } } //}}} //{{{ setLogWriter() method /** * Writes all currently logged messages to this stream if there was no * stream set previously, and sets the stream to write future log * messages to. * @param stream The writer * @since jEdit 3.2pre4 */ public static void setLogWriter(Writer stream) { if(Log.stream == null && stream != null) { try { if(wrap) { for(int i = logLineCount; i < log.length; i++) { stream.write(log[i]); stream.write(lineSep); } } for(int i = 0; i < logLineCount; i++) { stream.write(log[i]); stream.write(lineSep); } stream.flush(); } catch(Exception e) { // do nothing, who cares } } Log.stream = stream; } //}}} //{{{ flushStream() method /** * Flushes the log stream. * @since jEdit 2.6pre5 */ public static void flushStream() { if(stream != null) { try { stream.flush(); } catch(IOException io) { io.printStackTrace(realErr); } } } //}}} //{{{ closeStream() method /** * Closes the log stream. Should be done before your program exits. * @since jEdit 2.6pre5 */ public static void closeStream() { if(stream != null) { try { stream.close(); stream = null; } catch(IOException io) { io.printStackTrace(realErr); } } } //}}} //{{{ getLogListModel() method /** * Returns the list model for viewing the log contents. * @since jEdit 4.2pre1 */ public static ListModel getLogListModel() { return listModel; } //}}} //{{{ log() method /** * Logs a message. This method is thread-safe.

* * The following code sends a typical debugging message to the activity * log: *

Log.log(Log.DEBUG,this,"counter = " + counter);
* The corresponding activity log entry might read as follows: *
[debug] JavaParser: counter = 15
* * @param urgency The urgency; can be one of * Log.DEBUG, Log.MESSAGE, * Log.NOTICE, Log.WARNING, or * Log.ERROR. * @param source The source of the message, either an object or a * class instance. When writing log messages from macros, set * this parameter to BeanShell.class to make macro * errors easier to spot in the activity log. * @param message The message. This can either be a string or * an exception * * @since jEdit 2.2pre2 */ public static void log(int urgency, Object source, Object message) { String _source; if(source == null) { _source = Thread.currentThread().getName(); if(_source == null) { _source = Thread.currentThread().getClass().getName(); } } else if(source instanceof Class) _source = ((Class)source).getName(); else _source = source.getClass().getName(); int index = _source.lastIndexOf('.'); if(index != -1) _source = _source.substring(index+1); if(message instanceof Throwable) { _logException(urgency,source,(Throwable)message); } else { String _message = String.valueOf(message); // If multiple threads log stuff, we don't want // the output to get mixed up synchronized(LOCK) { StringTokenizer st = new StringTokenizer( _message,"\r\n"); int lineCount = 0; boolean oldWrap = wrap; while(st.hasMoreTokens()) { lineCount++; _log(urgency,_source,st.nextToken() .replace('\t',' ')); } listModel.update(lineCount,oldWrap); } } } //}}} //{{{ Private members //{{{ Instance variables private static Object LOCK = new Object(); private static String[] log; private static int logLineCount; private static boolean wrap; private static int level = WARNING; private static Writer stream; private static String lineSep; private static PrintStream realOut; private static PrintStream realErr; private static LogListModel listModel; //}}} //{{{ Class initializer static { level = WARNING; realOut = System.out; realErr = System.err; log = new String[MAXLINES]; lineSep = System.getProperty("line.separator"); listModel = new LogListModel(); } //}}} //{{{ createPrintStream() method private static PrintStream createPrintStream(final int urgency, final Object source) { return new PrintStream(new OutputStream() { public void write(int b) { byte[] barray = { (byte)b }; write(barray,0,1); } public void write(byte[] b, int off, int len) { String str = new String(b,off,len); log(urgency,source,str); } }); } //}}} //{{{ _logException() method private static void _logException(final int urgency, final Object source, final Throwable message) { PrintStream out = createPrintStream(urgency,source); synchronized(LOCK) { message.printStackTrace(out); } } //}}} //{{{ _log() method private static void _log(int urgency, String source, String message) { String fullMessage = "[" + urgencyToString(urgency) + "] " + source + ": " + message; try { log[logLineCount] = fullMessage; if(++logLineCount >= log.length) { wrap = true; logLineCount = 0; } if(stream != null) { stream.write(fullMessage); stream.write(lineSep); } } catch(Exception e) { e.printStackTrace(realErr); } if(urgency >= level) { if(urgency == ERROR) realErr.println(fullMessage); else realOut.println(fullMessage); } } //}}} //{{{ urgencyToString() method private static String urgencyToString(int urgency) { switch(urgency) { case DEBUG: return "debug"; case MESSAGE: return "message"; case NOTICE: return "notice"; case WARNING: return "warning"; case ERROR: return "error"; } throw new IllegalArgumentException("Invalid urgency: " + urgency); } //}}} //}}} //{{{ LogListModel class static class LogListModel implements ListModel { Vector listeners = new Vector(); private void fireIntervalAdded(int index1, int index2) { for(int i = 0; i < listeners.size(); i++) { ListDataListener listener = (ListDataListener) listeners.elementAt(i); listener.intervalAdded(new ListDataEvent(this, ListDataEvent.INTERVAL_ADDED, index1,index2)); } } private void fireIntervalRemoved(int index1, int index2) { for(int i = 0; i < listeners.size(); i++) { ListDataListener listener = (ListDataListener) listeners.elementAt(i); listener.intervalRemoved(new ListDataEvent(this, ListDataEvent.INTERVAL_REMOVED, index1,index2)); } } public void addListDataListener(ListDataListener listener) { listeners.addElement(listener); } public void removeListDataListener(ListDataListener listener) { listeners.removeElement(listener); } public Object getElementAt(int index) { if(wrap) { if(index < MAXLINES - logLineCount) return log[index + logLineCount]; else return log[index - MAXLINES + logLineCount]; } else return log[index]; } public int getSize() { if(wrap) return MAXLINES; else return logLineCount; } void update(final int lineCount, final boolean oldWrap) { if(lineCount == 0 || listeners.size() == 0) return; SwingUtilities.invokeLater(new Runnable() { public void run() { if(wrap) { if(oldWrap) fireIntervalRemoved(0,lineCount - 1); else { fireIntervalRemoved(0, logLineCount); } fireIntervalAdded( MAXLINES - lineCount + 1, MAXLINES); } else { fireIntervalAdded( logLineCount - lineCount + 1, logLineCount); } } }); } } //}}} }
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