logwriter.java

用Java写的面相对象的数据库管理系统

// You can redistribute this software and/or modify it under the terms of
// the Ozone Library License version 1 published by ozone-db.org.
//
// The original code and portions created by SMB are
// Copyright (C) 1997-2000 by SMB GmbH. All rights reserved.
//
// $Id: LogWriter.java,v 1.3 2000/10/28 16:55:21 daniela Exp $

package org.ozoneDB.util;

import java.io.*;
import java.util.*;
import org.ozoneDB.DxLib.*;


/**
 * @author <a href="http://www.softwarebuero.de/">SMB</a>
 * @version $Revision: 1.3 $Date: 2000/10/28 16:55:21 $
 */
public final class LogWriter {
    
    public final static int INFO = 1;
    public final static int WARN = 2;
    public final static int ERROR = 4;
    public final static int DEBUG = 8;
    public final static int DEBUG2 = 16;
    public final static int DEBUG3 = 32;
    
    protected final static String INFO_PREFIX = "[info] ";
    protected final static String WARN_PREFIX = "[warn] ";
    protected final static String ERROR_PREFIX = "[error]";
    protected final static String DEBUG_PREFIX = "[debug]";
    
    public final static int LINE_WIDTH = 70;
    
    protected DxBag logTargets;
    
    protected int allLevels;
    
    
    public LogWriter() {
        logTargets = new DxArrayBag();
    }
    
    
    /**
     * This method allows to quickly find out if there is any log target that
     * would receive entries of the specified level.
     */
    public boolean hasTarget( int level ) {
        return (allLevels & level) > 0;
    } 
    
    
    public void addLogTarget( OutputStream _out, int _levels ) {
        // set also lower debug levels when higher levels are requested
        _levels = (_levels & DEBUG3) > 0 ? _levels | DEBUG2 : _levels;
        _levels = (_levels & DEBUG2) > 0 ? _levels | DEBUG : _levels;
        
        addLogTarget( new PrintWriter( _out ), _levels );
    } 
    
    
    public void addLogTarget( PrintWriter _writer, int _levels ) {
        // set also lower debug levels when higher levels are requested
        _levels = (_levels & DEBUG3) > 0 ? _levels | DEBUG2 : _levels;
        _levels = (_levels & DEBUG2) > 0 ? _levels | DEBUG : _levels;
        
        logTargets.add( new LogTarget( _writer, _levels ) );
        allLevels = allLevels | _levels;
    } 
    
    
    public void newEntry( Object sender, String msg, int levels ) {
        newEntry( sender, msg, null, levels );
    } 
    
    
    public void newEntry( Object sender, String msg, Throwable e, int levels ) {
        //check if at least one of the specified levels is supported by
        //any of the LogTargets
        if ((allLevels & levels) > 0) {
            for (DxIterator it = logTargets.iterator(); it.next() != null;) {
                LogTarget logTarget = (LogTarget)it.object();
                if ((logTarget.levels & levels & INFO) > 0) {
                    printToWriter( logTarget.writer, sender, msg, INFO_PREFIX, e );
                } 
                if ((logTarget.levels & levels & WARN) > 0) {
                    printToWriter( logTarget.writer, sender, msg, WARN_PREFIX, e );
                } 
                if ((logTarget.levels & levels & ERROR) > 0) {
                    printToWriter( logTarget.writer, sender, msg, ERROR_PREFIX, e );
                } 
                if ((logTarget.levels & levels & (DEBUG | DEBUG2 | DEBUG3)) > 0) {
                    printToWriter( logTarget.writer, sender, msg, DEBUG_PREFIX, e );
                } 
            } 
        } 
    } 
    
    
    protected void printToWriter( PrintWriter writer, Object sender, String msg, String status, Throwable e ) {
        StringBuffer sb = new StringBuffer( 120 );
        sb.append( status );
        sb.append( '(' );
        String threadNum = String.valueOf( Thread.currentThread().hashCode() );
        sb.append( threadNum.substring( threadNum.length() - 3 ) );
        sb.append( ") " );
        sb.append( rawClassName( sender ) );
        sb.append( ": " );
        sb.append( msg );
        writer.println( sb );
        writer.flush();
        if (e != null) {
            // writer.print ("    exception: " + e.getMessage());
            printFormatedException( writer, e, LINE_WIDTH, "    " );
        } 
    } 
    
    
    public static String rawClassName( Object obj ) {
        if (obj != null) {
            String name = obj.getClass().getName();
            int index = name.lastIndexOf( '.' );
            return name.substring( index + 1 );
        } else {
            return "(null)";
        } 
    } 
    
    
    protected void printFormatedException( OutputStream out, Throwable e, int lineWidth, String pre ) {
        printFormatedException( new PrintWriter( out ), e, lineWidth, pre );
    } 
    
    
    protected void printFormatedException( PrintWriter out, Throwable e, int lineWidth, String pre ) {
        StringWriter buff = new StringWriter();
        e.printStackTrace( new PrintWriter( buff ) );
        StringTokenizer st = new StringTokenizer( buff.toString(), "\n" );
        while (st.hasMoreTokens()) {
            String line = st.nextToken();
            boolean firstSubLine = true;
            // while (line.length() > lineWidth) {
            do {
                int subLineLength = Math.min( lineWidth, line.length() );
                String subLine = line.substring( 0, subLineLength );
                line = line.substring( subLineLength );
                if (!firstSubLine) {
                    out.print( "        " );
                } 
                out.print( pre );
                out.println( subLine );
                firstSubLine = false;
            } while (line.length() > 0);
        } 
        out.flush();
    } 
    
}