Logger (jcabi-log 0.17.4 API)

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

```
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: ac620569f27bf9516414baf79724fcb31c1b5b0a $

Author:

Yegor Bugayenko (yegor256@gmail.com)

Method Summary

All Methods Static Methods Concrete 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`	`debugForced(Object source, String msg, Object... args)` Protocol one message, with `DEBUG` priority level without internal checking whether `DEBUG` level is enabled.
`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 void`	`infoForced(Object source, String msg, Object... args)` Protocol one message, with `INFO` priority level without internal checking whether `INFO` level is enabled.
`static boolean`	`isDebugEnabled(Object source)` Validates whether `DEBUG` priority level is enabled for this particular logger.
`static boolean`	`isEnabled(Level level, Object source)` Is the given logging level enabled?
`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`	`traceForced(Object source, String msg, Object... args)` Protocol one message, with `TRACE` priority level without internal checking whether `TRACE` level is enabled.
`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.
`static void`	`warnForced(Object source, String msg, Object... args)` Protocol one message, with `WARN` priority level without internal checking whether `WARN` level is enabled.
`static com.jcabi.log.SupplierLogger`	`withSupplier()` Log messages constructed from Suppliers.

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
  - traceForced
```
public static void traceForced(Object source,
                               String msg,
                               Object... args)
```
    Protocol one message, with TRACE priority level without internal checking whether TRACE level is enabled.
    
    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
  - debugForced
```
public static void debugForced(Object source,
                               String msg,
                               Object... args)
```
    Protocol one message, with DEBUG priority level without internal checking whether DEBUG level is enabled.
    
    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
  - infoForced
```
public static void infoForced(Object source,
                              String msg,
                              Object... args)
```
    Protocol one message, with INFO priority level without internal checking whether INFO level is enabled.
    
    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
  - warnForced
```
public static void warnForced(Object source,
                              String msg,
                              Object... args)
```
    Protocol one message, with WARN priority level without internal checking whether WARN level is enabled.
    
    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
  - isEnabled
```
public static boolean isEnabled(Level level,
                                Object source)
```
    Is the given logging level enabled?
    
    Parameters:
    
    level - The level of logging
    
    source - The source of the logging operation
    
    Returns:
    
    Is it enabled?
    
    Since:
    
    0.13
  - 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
    
    Suppressed Checkstyle violations:
    
    MagicNumberCheck (20 lines)
  - withSupplier
```
public static com.jcabi.log.SupplierLogger withSupplier()
```
    Log messages constructed from Suppliers. It is more efficient to use method referencing because the method won't be called unless the specified logging level is enabled. This saves you the effort of having to check if the level is enabled before calling the logging method. E.g.
```
     if (Logger.isDebugEnabled(this)) {
         Logger.debug(this, "Some %s", calculate());
     }
 
```
    turns into
```
     Logger.withSupplier().debug(this, "Some %s", this::calculate());
 
```
    and the calculate() method won't be called unless the debug level is active.
    Returns:
    
    Object containing methods for logging with Supplier-constructed messages

Class Logger

Method Summary

Methods inherited from class java.lang.Object

Method Detail

format

trace

trace

traceForced

debug

debug

debugForced

info

info

infoForced

warn

warn

warnForced

error

error

isTraceEnabled

isDebugEnabled

isInfoEnabled

isWarnEnabled

isEnabled

log

stream

withSupplier