/*
* Copyright 2001-2004 The Apache Software Foundation.
* Copyright 2005 Niclas Hedhman
*
* 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.
*/
/* NOTE!!!! This is NOT the original Jakarta Commons Logging, but an adaption
of its interface so that this Log4J OSGi bundle can export the JCL interface
but redirect permananently to the Log4J implementation
*/
package org.apache.commons.logging;
/**
* <p>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.</p>
*
* <p> The six logging levels used by <code>Log</code> are (in order):
* <ol>
* <li>trace (the least serious)</li>
* <li>debug</li>
* <li>info</li>
* <li>warn</li>
* <li>error</li>
* <li>fatal (the most serious)</li>
* </ol>
* 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.</p>
*
* <p>Performance is often a logging concern.
* By examining the appropriate property,
* a component can avoid expensive operations (producing information
* to be logged).</p>
*
* <p> For example,
* <code><pre>
* if (log.isDebugEnabled()) {
* ... do something expensive ...
* log.debug(theResult);
* }
* </pre></code>
* </p>
*
* <p>Configuration of the underlying logging system will generally be done
* external to the Logging APIs, through whatever mechanism is supported by
* that system.</p>
*
* @author <a href="mailto:sanders@apache.org">Scott Sanders</a>
* @author Rod Waldhoff
* @version $Id: Log.java,v 1.19 2004/06/06 21:16:04 rdonkin Exp $
*/
public interface Log
{
/**
* <p> Is debug logging currently enabled? </p>
*
* <p> Call this method to prevent having to perform expensive operations
* (for example, <code>String</code> concatenation)
* when the log level is more than debug. </p>
*
* @return true if Debug level is enabled
*/
boolean isDebugEnabled();
/**
* <p> Is error logging currently enabled? </p>
*
* <p> Call this method to prevent having to perform expensive operations
* (for example, <code>String</code> concatenation)
* when the log level is more than error. </p>
*
* @return true if Error level is enabled
*/
boolean isErrorEnabled();
/**
* <p> Is fatal logging currently enabled? </p>
*
* <p> Call this method to prevent having to perform expensive operations
* (for example, <code>String</code> concatenation)
* when the log level is more than fatal. </p>
*
* @return true if Fatal level is enabled
*/
boolean isFatalEnabled();
/**
* <p> Is info logging currently enabled? </p>
*
* <p> Call this method to prevent having to perform expensive operations
* (for example, <code>String</code> concatenation)
* when the log level is more than info. </p>
*
* @return true if Info level is enabled
*/
boolean isInfoEnabled();
/**
* <p> Is trace logging currently enabled? </p>
*
* <p> Call this method to prevent having to perform expensive operations
* (for example, <code>String</code> concatenation)
* when the log level is more than trace. </p>
*
* @return true if Trace level is enabled
*/
boolean isTraceEnabled();
/**
* <p> Is warn logging currently enabled? </p>
*
* <p> Call this method to prevent having to perform expensive operations
* (for example, <code>String</code> concatenation)
* when the log level is more than warn. </p>
*
* @return true if Warn level is enabled
*/
boolean isWarnEnabled();
/**
* <p> Log a message with trace log level. </p>
*
* @param message log this message
*/
void trace( Object message );
/**
* <p> Log an error with trace log level. </p>
*
* @param message log this message
* @param t log this cause
*/
void trace( Object message, Throwable t );
/**
* <p> Log a message with debug log level. </p>
*
* @param message log this message
*/
void debug( Object message );
/**
* <p> Log an error with debug log level. </p>
*
* @param message log this message
* @param t log this cause
*/
void debug( Object message, Throwable t );
/**
* <p> Log a message with info log level. </p>
*
* @param message log this message
*/
void info( Object message );
/**
* <p> Log an error with info log level. </p>
*
* @param message log this message
* @param t log this cause
*/
void info( Object message, Throwable t );
/**
* <p> Log a message with warn log level. </p>
*
* @param message log this message
*/
void warn( Object message );
/**
* <p> Log an error with warn log level. </p>
*
* @param message log this message
* @param t log this cause
*/
void warn( Object message, Throwable t );
/**
* <p> Log a message with error log level. </p>
*
* @param message log this message
*/
void error( Object message );
/**
* <p> Log an error with error log level. </p>
*
* @param message log this message
* @param t log this cause
*/
void error( Object message, Throwable t );
/**
* <p> Log a message with fatal log level. </p>
*
* @param message log this message
*/
void fatal( Object message );
/**
* <p> Log an error with fatal log level. </p>
*
* @param message log this message
* @param t log this cause
*/
void fatal( Object message, Throwable t );
/**
* Returns the LogLevel of the Logger.
* The LogLevels are
* <pre>
* Integer.MAX_INT = OFF
* FATAL = 50000
* ERROR = 40000
* WARN = 30000
* INFO = 20000
* DEBUG = 10000
* TRACE = 5000
* ALL = Integer.MIN_VALUE
* </pre>
*
* @return the numeric value of the current level.
*/
int getLogLevel();
}