Log (Apache Tomcat 8.0.53 API Documentation)

```
public interface Log
```
A simple logging interface abstracting logging APIs. In order to be instantiated successfully by LogFactory, classes that implement this interface must have a constructor that takes a single String parameter representing the "name" of this Log.

The six logging levels used by Log are (in order):
1. trace (the least serious)
2. debug
3. info
4. warn
5. error
6. fatal (the most serious)
The mapping of these log levels to the concepts used by the underlying logging system is implementation dependent. The implementation should ensure, though, that this ordering behaves as expected.

Performance is often a logging concern. By examining the appropriate property, a component can avoid expensive operations (producing information to be logged).

For example, if (log.isDebugEnabled()) { ... do something expensive ... log.debug(theResult); }

Configuration of the underlying logging system will generally be done external to the Logging APIs, through whatever mechanism is supported by that system.
Author:

Scott Sanders, Rod Waldhoff

Method Summary

Methods
Modifier and Type	Method and Description
`void`	`debug(java.lang.Object message)` Log a message with debug log level.
`void`	`debug(java.lang.Object message, java.lang.Throwable t)` Log an error with debug log level.
`void`	`error(java.lang.Object message)` Log a message with error log level.
`void`	`error(java.lang.Object message, java.lang.Throwable t)` Log an error with error log level.
`void`	`fatal(java.lang.Object message)` Log a message with fatal log level.
`void`	`fatal(java.lang.Object message, java.lang.Throwable t)` Log an error with fatal log level.
`void`	`info(java.lang.Object message)` Log a message with info log level.
`void`	`info(java.lang.Object message, java.lang.Throwable t)` Log an error with info log level.
`boolean`	`isDebugEnabled()` Is debug logging currently enabled?
`boolean`	`isErrorEnabled()` Is error logging currently enabled?
`boolean`	`isFatalEnabled()` Is fatal logging currently enabled?
`boolean`	`isInfoEnabled()` Is info logging currently enabled?
`boolean`	`isTraceEnabled()` Is trace logging currently enabled?
`boolean`	`isWarnEnabled()` Is warn logging currently enabled?
`void`	`trace(java.lang.Object message)` Log a message with trace log level.
`void`	`trace(java.lang.Object message, java.lang.Throwable t)` Log an error with trace log level.
`void`	`warn(java.lang.Object message)` Log a message with warn log level.
`void`	`warn(java.lang.Object message, java.lang.Throwable t)` Log an error with warn log level.

- Method Detail
  - isDebugEnabled
```
boolean isDebugEnabled()
```
    Is debug logging currently enabled?
    
    Call this method to prevent having to perform expensive operations (for example, String concatenation) when the log level is more than debug.
  - isErrorEnabled
```
boolean isErrorEnabled()
```
    Is error logging currently enabled?
    
    Call this method to prevent having to perform expensive operations (for example, String concatenation) when the log level is more than error.
  - isFatalEnabled
```
boolean isFatalEnabled()
```
    Is fatal logging currently enabled?
    
    Call this method to prevent having to perform expensive operations (for example, String concatenation) when the log level is more than fatal.
  - isInfoEnabled
```
boolean isInfoEnabled()
```
    Is info logging currently enabled?
    
    Call this method to prevent having to perform expensive operations (for example, String concatenation) when the log level is more than info.
  - isTraceEnabled
```
boolean isTraceEnabled()
```
    Is trace logging currently enabled?
    
    Call this method to prevent having to perform expensive operations (for example, String concatenation) when the log level is more than trace.
  - isWarnEnabled
```
boolean isWarnEnabled()
```
    Is warn logging currently enabled?
    
    Call this method to prevent having to perform expensive operations (for example, String concatenation) when the log level is more than warn.
  - trace
```
void trace(java.lang.Object message)
```
    Log a message with trace log level.
    
    Parameters:
    message - log this message
  - trace
```
void trace(java.lang.Object message,
         java.lang.Throwable t)
```
    Log an error with trace log level.
    
    Parameters:
    message - log this message
    t - log this cause
  - debug
```
void debug(java.lang.Object message)
```
    Log a message with debug log level.
    
    Parameters:
    message - log this message
  - debug
```
void debug(java.lang.Object message,
         java.lang.Throwable t)
```
    Log an error with debug log level.
    
    Parameters:
    message - log this message
    t - log this cause
  - info
```
void info(java.lang.Object message)
```
    Log a message with info log level.
    
    Parameters:
    message - log this message
  - info
```
void info(java.lang.Object message,
        java.lang.Throwable t)
```
    Log an error with info log level.
    
    Parameters:
    message - log this message
    t - log this cause
  - warn
```
void warn(java.lang.Object message)
```
    Log a message with warn log level.
    
    Parameters:
    message - log this message
  - warn
```
void warn(java.lang.Object message,
        java.lang.Throwable t)
```
    Log an error with warn log level.
    
    Parameters:
    message - log this message
    t - log this cause
  - error
```
void error(java.lang.Object message)
```
    Log a message with error log level.
    
    Parameters:
    message - log this message
  - error
```
void error(java.lang.Object message,
         java.lang.Throwable t)
```
    Log an error with error log level.
    
    Parameters:
    message - log this message
    t - log this cause
  - fatal
```
void fatal(java.lang.Object message)
```
    Log a message with fatal log level.
    
    Parameters:
    message - log this message
  - fatal
```
void fatal(java.lang.Object message,
         java.lang.Throwable t)
```
    Log an error with fatal log level.
    
    Parameters:
    message - log this message
    t - log this cause

Interface Log

Method Summary

Method Detail

isDebugEnabled

isErrorEnabled

isFatalEnabled

isInfoEnabled

isTraceEnabled

isWarnEnabled

trace

trace

debug

debug

info

info

warn

warn

error

error

fatal

fatal