/*
 * Copyright (C) 2008 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.internal.logging;

import android.util.Log;
import com.android.internal.util.FastPrintWriter;
import dalvik.system.DalvikLogging;
import dalvik.system.DalvikLogHandler;

import java.io.PrintWriter;
import java.io.StringWriter;
import java.util.logging.Formatter;
import java.util.logging.Handler;
import java.util.logging.Level;
import java.util.logging.LogRecord;
import java.util.logging.Logger;

Implements a Logger handler that writes to the Android log. The implementation is rather straightforward. The name of the logger serves as the log tag. Only the log levels need to be converted appropriately. For this purpose, the following mapping is being used: 

  

    
logger level
    
Android level
  
  

    

      SEVERE
    
    

      ERROR
    
  
  

    

      WARNING
    
    

      WARN
    
  
  

    

      INFO
    
    

      INFO
    
  
  

    

      CONFIG
    
    

      DEBUG
    
  
  

    

      FINE, FINER, FINEST
    
    

      VERBOSE
    
  

/**
 * Implements a {@link java.util.logging.Logger} handler that writes to the Android log. The
 * implementation is rather straightforward. The name of the logger serves as
 * the log tag. Only the log levels need to be converted appropriately. For
 * this purpose, the following mapping is being used:
 * 
 * <table>
 *   <tr>
 *     <th>logger level</th>
 *     <th>Android level</th>
 *   </tr>
 *   <tr>
 *     <td>
 *       SEVERE
 *     </td>
 *     <td>
 *       ERROR
 *     </td>
 *   </tr>
 *   <tr>
 *     <td>
 *       WARNING
 *     </td>
 *     <td>
 *       WARN
 *     </td>
 *   </tr>
 *   <tr>
 *     <td>
 *       INFO
 *     </td>
 *     <td>
 *       INFO
 *     </td>
 *   </tr>
 *   <tr>
 *     <td>
 *       CONFIG
 *     </td>
 *     <td>
 *       DEBUG
 *     </td>
 *   </tr>
 *   <tr>
 *     <td>
 *       FINE, FINER, FINEST
 *     </td>
 *     <td>
 *       VERBOSE
 *     </td>
 *   </tr>
 * </table>
 */
public class AndroidHandler extends Handler implements DalvikLogHandler {
    
Holds the formatter for all Android log handlers.
/**
     * Holds the formatter for all Android log handlers.
     */
    private static final Formatter THE_FORMATTER = new Formatter() {
        @Override
        public String format(LogRecord r) {
            Throwable thrown = r.getThrown();
            if (thrown != null) {
                StringWriter sw = new StringWriter();
                PrintWriter pw = new FastPrintWriter(sw, false, 256);
                sw.write(r.getMessage());
                sw.write("\n");
                thrown.printStackTrace(pw);
                pw.flush();
                return sw.toString();
            } else {
                return r.getMessage();
            }
        }
    };

    
Constructs a new instance of the Android log handler.
/**
     * Constructs a new instance of the Android log handler.
     */
    public AndroidHandler() {
        setFormatter(THE_FORMATTER);
    }

    @Override
    public void close() {
        // No need to close, but must implement abstract method.
    }

    @Override
    public void flush() {
        // No need to flush, but must implement abstract method.
    }

    @Override
    public void publish(LogRecord record) {
        int level = getAndroidLevel(record.getLevel());
        String tag = DalvikLogging.loggerNameToTag(record.getLoggerName());
        if (!Log.isLoggable(tag, level)) {
            return;
        }

        try {
            String message = getFormatter().format(record);
            Log.println(level, tag, message);
        } catch (RuntimeException e) {
            Log.e("AndroidHandler", "Error logging message.", e);
        }
    }

    public void publish(Logger source, String tag, Level level, String message) {
        // TODO: avoid ducking into native 2x; we aren't saving any formatter calls
        int priority = getAndroidLevel(level);
        if (!Log.isLoggable(tag, priority)) {
            return;
        }

        try {
            Log.println(priority, tag, message);
        } catch (RuntimeException e) {
            Log.e("AndroidHandler", "Error logging message.", e);
        }
    }

    
Converts a Logger logging level into an Android one. 
Params:
level – The Logger logging level.
Returns:
The resulting Android logging level./**
     * Converts a {@link java.util.logging.Logger} logging level into an Android one.
     *
     * @param level The {@link java.util.logging.Logger} logging level.
     *
     * @return The resulting Android logging level.
     */
    static int getAndroidLevel(Level level) {
        int value = level.intValue();
        if (value >= 1000) { // SEVERE
            return Log.ERROR;
        } else if (value >= 900) { // WARNING
            return Log.WARN;
        } else if (value >= 800) { // INFO
            return Log.INFO;
        } else {
            return Log.DEBUG;
        }
    }
}