/*
* 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;
/**
* 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 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;
/**
* Exception class used to capture a stack trace in {@link #wtf}.
*/
private static class TerribleFailure extends Exception {
TerribleFailure(String msg, Throwable cause) {
super(msg, cause);
}
}
/**
* Interface to handle terrible failures from {@link #wtf}.
*
* @hide
*/
public interface TerribleFailureHandler {
void onTerribleFailure(String tag, TerribleFailure what, boolean system);
}
private static TerribleFailureHandler sWtfHandler = new TerribleFailureHandler() {
public void onTerribleFailure(String tag, TerribleFailure what, boolean system) {
System.out.println(tag + ":" + what.getMessage());
}
};
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_native(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_native(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_native(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_native(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_native(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_native(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_native(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_native(LOG_ID_MAIN, WARN, tag, msg + '\n' + getStackTraceString(tr));
}
/**
* Checks to see whether or not a log for the specified tag is loggable at the specified level.
*
* The default level of any tag is set to INFO. This means that any level above and including INFO will be logged. Before you make any calls to a logging
* method you should check to see if your tag should be logged. You can change the default level by setting a system property: 'setprop
* log.tag.<YOUR_LOG_TAG> <LEVEL>' Where level is either VERBOSE, DEBUG, INFO, WARN, ERROR, ASSERT, or SUPPRESS. SUPPRESS will turn off all logging for
* your tag. You can also create a local.prop file that with the following in it: 'log.tag.<YOUR_LOG_TAG>=<LEVEL>' and place that in /data/local.prop.
*
* @param tag The tag to check.
* @param level The level to check.
* @return Whether or not that this is allowed to be logged.
* @throws IllegalArgumentException is thrown if the tag.length() > 23.
*/
public static native boolean isLoggable(String tag, int level);
/*
* 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_native(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_native(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_native(LOG_ID_MAIN, ERROR, tag, msg + '\n' + getStackTraceString(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 static int wtf(String tag, String msg) {
return wtf(LOG_ID_MAIN, tag, msg, null, false, false);
}
/**
* Like {@link #wtf(String, String)}, but also writes to the log the full call stack.
*
* @hide
*/
public static int wtfStack(String tag, String msg) {
return wtf(LOG_ID_MAIN, tag, msg, null, true, false);
}
/**
* 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 static int wtf(String tag, Throwable tr) {
return wtf(LOG_ID_MAIN, tag, tr.getMessage(), tr, false, false);
}
/**
* 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 static int wtf(String tag, String msg, Throwable tr) {
return wtf(LOG_ID_MAIN, tag, msg, tr, false, false);
}
static int wtf(int logId, String tag, String msg, Throwable tr, boolean localStack,
boolean system) {
TerribleFailure what = new TerribleFailure(msg, tr);
int bytes = println_native(logId, ASSERT, tag, msg + '\n'
+ getStackTraceString(localStack ? what : tr));
sWtfHandler.onTerribleFailure(tag, what, system);
return bytes;
}
static void wtfQuiet(int logId, String tag, String msg, boolean system) {
TerribleFailure what = new TerribleFailure(msg, null);
sWtfHandler.onTerribleFailure(tag, what, system);
}
/**
* Sets the terrible failure handler, for testing.
*
* @return the old handler
*
* @hide
*/
public static TerribleFailureHandler setWtfHandler(TerribleFailureHandler handler) {
if (handler == null) {
throw new NullPointerException("handler == null");
}
TerribleFailureHandler oldHandler = sWtfHandler;
sWtfHandler = handler;
return oldHandler;
}
/**
* 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_native(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
*/
public static native int println_native(int bufID,
int priority, String tag, String msg);
}