Log.java

/*
 * Copyright 2011-2012 Paddy Byers
 *
 *   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.
 */

/*
 * 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 org.webinos.android.util;

/**
 * Platform-independent logger, inspired by Android
 */

/**
 * API for sending log output.
 *
 * <p>Generally, use the Log.v() Log.d() Log.i() Log.w() and Log.e()
 * methods.
 *
 * <p>The order in terms of verbosity, from least to most is
 * ERROR, WARN, INFO, DEBUG, VERBOSE.  Verbose should never be compiled
 * into an application except during development.  Debug logs are compiled
 * in but stripped at runtime.  Error, warning and info logs are always kept.
 *
 * <p><b>Tip:</b> A good convention is to declare a <code>TAG</code> constant
 * in your class:
 *
 * <pre>private static final String TAG = "MyActivity";</pre>
 *
 * and use that in subsequent calls to the log methods.
 * </p>
 *
 * <p><b>Tip:</b> Don't forget that when you make a call like
 * <pre>Log.v(TAG, "index=" + i);</pre>
 * that when you're building the string to pass into Log.d, the compiler uses a
 * StringBuilder and at least three allocations occur: the StringBuilder
 * itself, the buffer, and the String object.  Realistically, there is also
 * another buffer allocation and copy, and even more pressure on the gc.
 * That means that if your log message is filtered out, you might be doing
 * significant work and incurring significant overhead.
 */

public interface 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;

    /**
     * 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 int v(String tag, String 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 int v(String tag, String msg, Throwable 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 int d(String tag, String 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 int d(String tag, String msg, Throwable 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 int i(String tag, String 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 int i(String tag, String msg, Throwable 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 int w(String tag, String 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 int w(String tag, String msg, Throwable 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 int w(String tag, Throwable 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 int e(String tag, String 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 int e(String tag, String msg, Throwable tr);

    /**
     * What a Terrible Failure: Report a condition that should never happen.
     * The error will always be logged at level ASSERT with the call stack.
     * Depending on system configuration, a report may be added to the
     * {@link android.os.DropBoxManager} and/or the process may be terminated
     * immediately with an error dialog.
     * @param tag Used to identify the source of a log message.
     * @param msg The message you would like logged.
     */
    public int wtf(String tag, String msg);

    /**
     * What a Terrible Failure: Report an exception that should never happen.
     * Similar to {@link #wtf(String, String)}, with an exception to log.
     * @param tag Used to identify the source of a log message.
     * @param tr An exception to log.
     */
    public int wtf(String tag, Throwable tr);

    /**
     * What a Terrible Failure: Report an exception that should never happen.
     * Similar to {@link #wtf(String, Throwable)}, with a message as well.
     * @param tag Used to identify the source of a log message.
     * @param msg The message you would like logged.
     * @param tr An exception to log.  May be null.
     */
    public int wtf(String tag, String msg, Throwable tr);

}