Logger (jcabi-log 0.12.2 API)

java.lang.Object
- com.jcabi.log.Logger

```
@Immutable
public final class Logger
extends Object
```
Universal logger, and adapter between your app and SLF4J API.
Instead of relying on some logging engine you can use this class, which transforms all messages to SLF4J. This approach gives you a perfect decoupling of business logic and logging mechanism. All methods in the class are called statically, without the necessity to instantiate the class.
Use it like this in any class, and in any package:
```
 package com.example.XXX;
 import com.jcabi.log.Logger;
 public class MyClass {
   public void foo(Integer num) {
     Logger.info(this, "foo(%d) just called", num);
   }
 }
```
Or statically (pay attention to MyClass.class):
```
 public class MyClass {
   public static void foo(Integer num) {
     Logger.info(MyClass.class, "foo(%d) just called", num);
   }
 }
```
Exact binding between SLF4J and logging facility has to be specified in pom.xml of your project (or in classpath directly).
For performance reasons in most cases before sending a TRACE or DEBUG log message you may check whether this logging level is enabled in the project, e.g.:
```
 //...
 if (Logger.isTraceEnabled(this)) {
   Logger.trace(this, "#foo() called");
 }
 //...
```
There is only one reason to do so - if you want to save time spent on preparing of the arguments. By default, such a call is made inside every method of Logger class.
Since:

0.1

Version:

$Id$

Author:

Yegor Bugayenko (yegor@tpc2.com)

Method Summary

Methods
Modifier and Type	Method and Description
`static void`	`debug(Object source, String msg)` Protocol one message, with `DEBUG` priority level.
`static void`	`debug(Object source, String msg, Object... args)` Protocol one message, with `DEBUG` priority level.
`static void`	`error(Object source, String msg)` Protocol one message, with `ERROR` priority level.
`static void`	`error(Object source, String msg, Object... args)` Protocol one message, with `ERROR` priority level.
`static String`	`format(String fmt, Object... args)` Format one string.
`static void`	`info(Object source, String msg)` Protocol one message, with `INFO` priority level.
`static void`	`info(Object source, String msg, Object... args)` Protocol one message, with `INFO` priority level.
`static boolean`	`isDebugEnabled(Object source)` Validates whether `DEBUG` priority level is enabled for this particular logger.
`static boolean`	`isInfoEnabled(Object source)` Validates whether `INFO` priority level is enabled for this particular logger.
`static boolean`	`isTraceEnabled(Object source)` Validates whether `TRACE` priority level is enabled for this particular logger.
`static boolean`	`isWarnEnabled(Object source)` Validates whether `INFO` priority level is enabled for this particular logger.
`static void`	`log(Level level, Object source, String msg, Object... args)` Log one line using the logging level specified.
`static OutputStream`	`stream(Level level, Object source)` Returns an `OutputStream`, which converts all incoming data into logging lines (separated by `\x0A` in UTF-8).
`static void`	`trace(Object source, String msg)` Protocol one message, with `TRACE` priority level.
`static void`	`trace(Object source, String msg, Object... args)` Protocol one message, with `TRACE` priority level.
`static void`	`warn(Object source, String msg)` Protocol one message, with `WARN` priority level.
`static void`	`warn(Object source, String msg, Object... args)` Protocol one message, with `WARN` priority level.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Method Detail
  - format
```
public static String format(String fmt,
            Object... args)
```
    Format one string.
    
    Parameters:
    fmt - The format
    args - List of arbitrary arguments
    
    Returns:
    Formatted string
  - trace
```
public static void trace(Object source,
         String msg)
```
    Protocol one message, with TRACE priority level.
    
    Parameters:
    source - The source of the logging operation
    msg - The text message to be logged
    Since:
    
    0.7.11
  - trace
```
public static void trace(Object source,
         String msg,
         Object... args)
```
    Protocol one message, with TRACE priority level.
    
    Parameters:
    source - The source of the logging operation
    msg - The text message to be logged, with meta-tags
    args - List of arguments
  - debug
```
public static void debug(Object source,
         String msg)
```
    Protocol one message, with DEBUG priority level.
    
    Parameters:
    source - The source of the logging operation
    msg - The text message to be logged, with meta-tags
    Since:
    
    0.7.11
  - debug
```
public static void debug(Object source,
         String msg,
         Object... args)
```
    Protocol one message, with DEBUG priority level.
    
    Parameters:
    source - The source of the logging operation
    msg - The text message to be logged, with meta-tags
    args - List of arguments
  - info
```
public static void info(Object source,
        String msg)
```
    Protocol one message, with INFO priority level.
    
    Parameters:
    source - The source of the logging operation
    msg - The text message to be logged
    Since:
    
    0.7.11
  - info
```
public static void info(Object source,
        String msg,
        Object... args)
```
    Protocol one message, with INFO priority level.
    
    Parameters:
    source - The source of the logging operation
    msg - The text message to be logged, with meta-tags
    args - List of arguments
  - warn
```
public static void warn(Object source,
        String msg)
```
    Protocol one message, with WARN priority level.
    
    Parameters:
    source - The source of the logging operation
    msg - The text message to be logged
    Since:
    
    0.7.11
  - warn
```
public static void warn(Object source,
        String msg,
        Object... args)
```
    Protocol one message, with WARN priority level.
    
    Parameters:
    source - The source of the logging operation
    msg - The text message to be logged, with meta-tags
    args - List of arguments
  - error
```
public static void error(Object source,
         String msg)
```
    Protocol one message, with ERROR priority level.
    
    Parameters:
    source - The source of the logging operation
    msg - The text message to be logged
    Since:
    
    0.7.11
  - error
```
public static void error(Object source,
         String msg,
         Object... args)
```
    Protocol one message, with ERROR priority level.
    
    Parameters:
    source - The source of the logging operation
    msg - The text message to be logged, with meta-tags
    args - List of arguments
  - isTraceEnabled
```
public static boolean isTraceEnabled(Object source)
```
    Validates whether TRACE priority level is enabled for this particular logger.
    
    Parameters:
    source - The source of the logging operation
    
    Returns:
    Is it enabled?
  - isDebugEnabled
```
public static boolean isDebugEnabled(Object source)
```
    Validates whether DEBUG priority level is enabled for this particular logger.
    
    Parameters:
    source - The source of the logging operation
    
    Returns:
    Is it enabled?
  - isInfoEnabled
```
public static boolean isInfoEnabled(Object source)
```
    Validates whether INFO priority level is enabled for this particular logger.
    
    Parameters:
    source - The source of the logging operation
    
    Returns:
    Is it enabled?
    Since:
    
    0.5
  - isWarnEnabled
```
public static boolean isWarnEnabled(Object source)
```
    Validates whether INFO priority level is enabled for this particular logger.
    
    Parameters:
    source - The source of the logging operation
    
    Returns:
    Is it enabled?
    Since:
    
    0.5
  - log
```
public static void log(Level level,
       Object source,
       String msg,
       Object... args)
```
    Log one line using the logging level specified.
    
    Parameters:
    level - The level of logging
    source - The source of the logging operation
    msg - The text message to be logged
    args - Optional arguments for string formatting
    Since:
    
    0.8
    
    Suppressed Checkstyle violations:
    
    ParameterNumber (4 lines)
  - stream
```
public static OutputStream stream(Level level,
                  Object source)
```
    Returns an OutputStream, which converts all incoming data into logging lines (separated by \x0A in UTF-8).
    
    Parameters:
    level - The level of logging
    source - The source of the logging operation
    
    Returns:
    Output stream directly pointed to the logging facility
    Since:
    
    0.8
    
    See Also:
    some discussion

Class Logger

Method Summary

Methods inherited from class java.lang.Object

Method Detail

format

trace

trace

debug

debug

info

info

warn

warn

error

error

isTraceEnabled

isDebugEnabled

isInfoEnabled

isWarnEnabled

log

stream