Logger.java

/*
 * PhoneGap is available under *either* the terms of the modified BSD license *or* the
 * MIT License (2008). See http://opensource.org/licenses/alphabetical for full text.
 * 
 * Copyright (c) 2005-2010, Nitobi Software Inc.
 * Copyright (c) 2010, IBM Corporation
 */
package com.phonegap.util;

import java.util.Date;

import net.rim.device.api.i18n.SimpleDateFormat;
import net.rim.device.api.system.EventLogger;

import com.phonegap.PhoneGapExtension;

/**
 * Logger provides a mechanism to log the the Blackberry Event Log.  It uses
 * the Blackberry EventLogger class.  
 * 
 * The Event Log can be viewed on Blackberry simulators using Tools > Show Event
 * Log, or on physical devices by pressing the <code>Alt</code> key, followed by
 * the <code>LGLG</code> key combination.
 * 
 * To enable event logging, you must first call <code>enableLogging</code>.
 * 
 * Logger also provides methods to write to <code>System.out</code> and 
 * <code>System.err</code>.
 */
public class Logger {

    /**
     * Application name
     */
    protected static String appName;
    
    /**
     *  Application GUID
     */
    protected static long appID;

    /**
     *  Used to format dates into a standard format
     */
    private static final SimpleDateFormat dateFormat = 
        new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS");

    /**
     * Invoke this method to enable logging to the BlackBerry Event Log.  
     */
    public static void enableLogging() {
        appID = PhoneGapExtension.getAppID();
        appName = PhoneGapExtension.getAppName(); 
        if (EventLogger.register(appID, appName, EventLogger.VIEWER_STRING)) {
            log("Logger enabled: " + "GUID=" + appID + ", name=" + appName);
        }
        else {
            log("EventLogger registration failed.");
        }
    }

    /**
     * Sets the minimum logging level.
     */	
    public static void setMinimumLoggingLevel(int level) {
        EventLogger.setMinimumLevel(level);
    }

    /**
     * Logs formatted message to Event Log with ALWAYS_LOG level.
     */
    public static void log(String msg) {
        logEvent(msg, EventLogger.ALWAYS_LOG);
    }

    /**
     * Logs formatted message to Event Log with DEBUG_INFO level.
     */
    public static void debug(String msg) {
        logEvent(msg, EventLogger.DEBUG_INFO);
    }

    /**
     * Logs formatted message to Event Log with INFORMATION level.
     */
    public static void info(String msg) {
        logEvent(msg, EventLogger.INFORMATION);
    }

    /**
     * Logs formatted message to Event Log with WARNING level.
     */
    public static void warn(String msg) {
        logEvent(msg, EventLogger.WARNING);
    }

    /**
     * Logs formatted message to Event Log with ERROR level.
     */
    public static void error(String msg) {
        logEvent(msg, EventLogger.ERROR);
    }

    /**
     * Logs formatted message to Event Log with SEVERE_ERROR level.
     */
    public static void severe(String msg) {
        logEvent(msg, EventLogger.SEVERE_ERROR);
    }

    /**
     * Prints unformatted message to System.out.
     */
    public static void out(String msg) {
        System.out.println(msg);
    }

    /**
     * Prints unformatted message to System.err.
     */
    public static void err(String msg, Throwable t) {
        System.err.println(msg);
        t.printStackTrace();
    }

    /**
     * Logs formatted message to Event Log (if enabled) and System.out.
     */
    private static void logEvent(String msg, int level) {
        String message = formatMessage(msg);
        EventLogger.logEvent(appID, message.getBytes(), level);
        out(message);
    }

    private static String formatMessage(String msg) {
        StringBuffer sb = new StringBuffer();
        sb.append(appName);
        sb.append(" [");
        sb.append(dateFormat.format(new Date()));
        sb.append("]: ");
        sb.append(msg);
        return sb.toString();
    }
}