Logging.java

//    ---------------------------------------------------------------------------
//    jWebSocket - Shared Logging Support
//    Copyright (c) 2010 Alexander Schulze, Innotrade GmbH
//    ---------------------------------------------------------------------------
//    This program 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 3 of the License, or (at your
//    option) 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 Lesser General Public License for
//    more details.
//    You should have received a copy of the GNU Lesser General Public License along
//    with this program; if not, see <http://www.gnu.org/licenses/lgpl.html>.
//    ---------------------------------------------------------------------------
package org.jwebsocket.logging;

import org.apache.log4j.Logger;
import org.jwebsocket.config.JWebSocketConfig;
import org.jwebsocket.config.xml.LoggingConfig;

/**
 * Provides the common used jWebSocket logging support based on Apache's log4j.
 *
 * @author Alexander Schulze (aschulze, Innotrade GmbH, jWebSocket.org)
 */
public class Logging {

    private static boolean mIsStackTraceEnabled = false;
    /**
     * Log output is send to the console (stdout).
     */
    public final static int CONSOLE = 0;
    /**
     * Log output is send to a rolling file.
     */
    public final static int ROLLING_FILE = 1;
    /**
     * Log output is send to a single file.
     */
    public final static int SINGLE_FILE = 2;
    private static int mReloadDelay = 20000;

    /**
     * Initializes the jWebSocket logging system with the given log level. All
     * subsequently instantiated class specific loggers will use this setting.
     *
     * @param aReloadDelay
     */
    public static void initLogs(Integer aReloadDelay) {
        if (aReloadDelay != null) {
            mReloadDelay = aReloadDelay;
        }
    }

    /**
     *
     * @param aLoggingConfig
     */
    public static void initLogs(LoggingConfig aLoggingConfig) {
        if (aLoggingConfig != null) {
            initLogs(aLoggingConfig.getReloadDelay());
        }
    }

    /**
     *
     * @return
     */
    public static boolean isStackTraceEnabled() {
        return mIsStackTraceEnabled;
    }

    /**
     *
     * @param aEnabled
     */
    public static void setStackTraceEnabled(boolean aEnabled) {
        mIsStackTraceEnabled = aEnabled;
    }

    /**
     *
     * @param aThrowable
     * @return
     */
    public static String getStackTraceAsString(Throwable aThrowable) {
        final StringBuilder result = new StringBuilder("");
        for (StackTraceElement lElement : aThrowable.getStackTrace()) {
            result.append(lElement);
            result.append("\n");
        }
        return result.toString();
    }

    /**
     *
     * @param aException
     * @return
     */
    public static String getExceptionMessage(Exception aException) {
        return aException.getMessage()
                + (mIsStackTraceEnabled ? "\n" + getStackTraceAsString(aException) : "");
    }

    /**
     *
     * @param aException
     * @param aHint
     * @return
     */
    public static String getSimpleExceptionMessage(Exception aException, String aHint) {
        return aException.getClass().getSimpleName()
                + " on " + aHint + ": "
                + getExceptionMessage(aException);
    }

    /**
     * closes the log file. Take care that no further lines are appended to the
     * logs after it has been closed!
     */
    public static void exitLogs() {
    }

    /**
     * Returns a logger for a certain class by using the jWebSocket settings for
     * logging and ignoring inherited log4j settings.
     *
     * @param aClass
     * @return Logger the new logger for the given class.
     */
    public static Logger getLogger(Class aClass) {
        return JWebSocketConfig.getLogger();
    }

    /**
     *
     * @return
     */
    public static Logger getLogger() {
        return JWebSocketConfig.getLogger();
    }
}