Log.java

/*
 * Copyright (C) 2006 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 android.util;

import java.io.PrintWriter;
import java.io.StringWriter;
import java.net.UnknownHostException;

/**
 * Mock Log implementation for testing on non android host.
 */
public final class Log {

	/**
	 * Priority constant for the println method; use Log.v.
	 */
	public static final int VERBOSE = 2;

	/**
	 * Priority constant for the println method; use Log.d.
	 */
	public static final int DEBUG = 3;

	/**
	 * Priority constant for the println method; use Log.i.
	 */
	public static final int INFO = 4;

	/**
	 * Priority constant for the println method; use Log.w.
	 */
	public static final int WARN = 5;

	/**
	 * Priority constant for the println method; use Log.e.
	 */
	public static final int ERROR = 6;

	/**
	 * Priority constant for the println method.
	 */
	public static final int ASSERT = 7;

	private Log() {}

	/**
	 * Send a {@link #VERBOSE} log message.
	 * 
	 * @param tag
	 *            Used to identify the source of a log message. It usually
	 *            identifies the class or activity where the log call occurs.
	 * @param msg
	 *            The message you would like logged.
	 */
	public static int v(String tag, String msg) {
		return println(LOG_ID_MAIN, VERBOSE, tag, msg);
	}

	/**
	 * Send a {@link #VERBOSE} log message and log the exception.
	 * 
	 * @param tag
	 *            Used to identify the source of a log message. It usually
	 *            identifies the class or activity where the log call occurs.
	 * @param msg
	 *            The message you would like logged.
	 * @param tr
	 *            An exception to log
	 */
	public static int v(String tag, String msg, Throwable tr) {
		return println(LOG_ID_MAIN, VERBOSE, tag, msg + '\n' + getStackTraceString(tr));
	}

	/**
	 * Send a {@link #DEBUG} log message.
	 * 
	 * @param tag
	 *            Used to identify the source of a log message. It usually
	 *            identifies the class or activity where the log call occurs.
	 * @param msg
	 *            The message you would like logged.
	 */
	public static int d(String tag, String msg) {
		return println(LOG_ID_MAIN, DEBUG, tag, msg);
	}

	/**
	 * Send a {@link #DEBUG} log message and log the exception.
	 * 
	 * @param tag
	 *            Used to identify the source of a log message. It usually
	 *            identifies the class or activity where the log call occurs.
	 * @param msg
	 *            The message you would like logged.
	 * @param tr
	 *            An exception to log
	 */
	public static int d(String tag, String msg, Throwable tr) {
		return println(LOG_ID_MAIN, DEBUG, tag, msg + '\n' + getStackTraceString(tr));
	}

	/**
	 * Send an {@link #INFO} log message.
	 * 
	 * @param tag
	 *            Used to identify the source of a log message. It usually
	 *            identifies the class or activity where the log call occurs.
	 * @param msg
	 *            The message you would like logged.
	 */
	public static int i(String tag, String msg) {
		return println(LOG_ID_MAIN, INFO, tag, msg);
	}

	/**
	 * Send a {@link #INFO} log message and log the exception.
	 * 
	 * @param tag
	 *            Used to identify the source of a log message. It usually
	 *            identifies the class or activity where the log call occurs.
	 * @param msg
	 *            The message you would like logged.
	 * @param tr
	 *            An exception to log
	 */
	public static int i(String tag, String msg, Throwable tr) {
		return println(LOG_ID_MAIN, INFO, tag, msg + '\n' + getStackTraceString(tr));
	}

	/**
	 * Send a {@link #WARN} log message.
	 * 
	 * @param tag
	 *            Used to identify the source of a log message. It usually
	 *            identifies the class or activity where the log call occurs.
	 * @param msg
	 *            The message you would like logged.
	 */
	public static int w(String tag, String msg) {
		return println(LOG_ID_MAIN, WARN, tag, msg);
	}

	/**
	 * Send a {@link #WARN} log message and log the exception.
	 * 
	 * @param tag
	 *            Used to identify the source of a log message. It usually
	 *            identifies the class or activity where the log call occurs.
	 * @param msg
	 *            The message you would like logged.
	 * @param tr
	 *            An exception to log
	 */
	public static int w(String tag, String msg, Throwable tr) {
		return println(LOG_ID_MAIN, WARN, tag, msg + '\n' + getStackTraceString(tr));
	}

	/*
	 * Send a {@link #WARN} log message and log the exception.
	 * 
	 * @param tag Used to identify the source of a log message. It usually
	 * identifies the class or activity where the log call occurs.
	 * 
	 * @param tr An exception to log
	 */
	public static int w(String tag, Throwable tr) {
		return println(LOG_ID_MAIN, WARN, tag, getStackTraceString(tr));
	}

	/**
	 * Send an {@link #ERROR} log message.
	 * 
	 * @param tag
	 *            Used to identify the source of a log message. It usually
	 *            identifies the class or activity where the log call occurs.
	 * @param msg
	 *            The message you would like logged.
	 */
	public static int e(String tag, String msg) {
		return println(LOG_ID_MAIN, ERROR, tag, msg);
	}

	/**
	 * Send a {@link #ERROR} log message and log the exception.
	 * 
	 * @param tag
	 *            Used to identify the source of a log message. It usually
	 *            identifies the class or activity where the log call occurs.
	 * @param msg
	 *            The message you would like logged.
	 * @param tr
	 *            An exception to log
	 */
	public static int e(String tag, String msg, Throwable tr) {
		return println(LOG_ID_MAIN, ERROR, tag, msg + '\n' + getStackTraceString(tr));
	}

	/**
	 * Handy function to get a loggable stack trace from a Throwable
	 * 
	 * @param tr
	 *            An exception to log
	 */
	public static String getStackTraceString(Throwable tr) {
		if (tr == null) {
			return "";
		}

		// This is to reduce the amount of log spew that apps do in the
		// non-error
		// condition of the network being unavailable.
		Throwable t = tr;
		while (t != null) {
			if (t instanceof UnknownHostException) {
				return "";
			}
			t = t.getCause();
		}

		StringWriter sw = new StringWriter();
		PrintWriter pw = new PrintWriter(sw);
		tr.printStackTrace(pw);
		pw.flush();
		return sw.toString();
	}

	/**
	 * Low-level logging call.
	 * 
	 * @param priority
	 *            The priority/type of this log message
	 * @param tag
	 *            Used to identify the source of a log message. It usually
	 *            identifies the class or activity where the log call occurs.
	 * @param msg
	 *            The message you would like logged.
	 * @return The number of bytes written.
	 */
	public static int println(int priority, String tag, String msg) {
		return println(LOG_ID_MAIN, priority, tag, msg);
	}

	/**
	 * @hide
	 */
	public static final int LOG_ID_MAIN = 0;
	/**
	 * @hide
	 */
	public static final int LOG_ID_RADIO = 1;
	/**
	 * @hide
	 */
	public static final int LOG_ID_EVENTS = 2;
	/**
	 * @hide
	 */
	public static final int LOG_ID_SYSTEM = 3;
	/**
	 * @hide
	 */
	public static final int LOG_ID_CRASH = 4;

	/**
	 * @hide
	 */
	@SuppressWarnings("unused")
	public static int println(int bufID, int priority, String tag, String msg) {
		System.out.println("P" + priority + "[" + tag + "]" + msg);
		return 0;
	}
}