File Doc Category Size Date Package
Log.java API Doc Android 1.5 API 6610 Wed May 06 22:41:10 BST 2009 org.apache.commons.logging

Log

public interface Log

A simple logging interface abstracting logging APIs. In order to be instantiated successfully by {@link 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):

trace (the least serious)
debug
info
warn
error
fatal (the most serious)

The mapping of these log levels to the concepts used by the underlying logging system is implementation dependent. The implemention 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
author: Rod Waldhoff
version: $Id: Log.java 381838 2006-02-28 23:57:11Z skitching $

Fields Summary
Constructors Summary
Methods Summary
public void debug(java.lang.Object message, java.lang.Throwable t)
Log an error with debug log level.
param
message log this message
param
t log this cause
public void debug(java.lang.Object message)
Log a message with debug log level.
param
message log this message
public void error(java.lang.Object message)
Log a message with error log level.
param
message log this message
public void error(java.lang.Object message, java.lang.Throwable t)
Log an error with error log level.
param
message log this message
param
t log this cause
public void fatal(java.lang.Object message)
Log a message with fatal log level.
param
message log this message
public void fatal(java.lang.Object message, java.lang.Throwable t)
Log an error with fatal log level.
param
message log this message
param
t log this cause
public void info(java.lang.Object message)
Log a message with info log level.
param
message log this message
public void info(java.lang.Object message, java.lang.Throwable t)
Log an error with info log level.
param
message log this message
param
t log this cause
public 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.
return
true if debug is enabled in the underlying logger.
public 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.
return
true if error is enabled in the underlying logger.
public 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.
return
true if fatal is enabled in the underlying logger.
public 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.
return
true if info is enabled in the underlying logger.
public 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.
return
true if trace is enabled in the underlying logger.
public 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.
return
true if warn is enabled in the underlying logger.
public void trace(java.lang.Object message)
Log a message with trace log level.
param
message log this message
public void trace(java.lang.Object message, java.lang.Throwable t)
Log an error with trace log level.
param
message log this message
param
t log this cause
public void warn(java.lang.Object message)
Log a message with warn log level.
param
message log this message
public void warn(java.lang.Object message, java.lang.Throwable t)
Log an error with warn log level.
param
message log this message
param
t log this cause