/*
* Copyright 2001-2004 The Apache Software Foundation.
*
* 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.
*/
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 381838 2006-02-28 23:57:11Z skitching $
*/
public interface Log {
// ----------------------------------------------------- Logging Properties
/**
* <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 is enabled in the underlying logger.
*/
public 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 is enabled in the underlying logger.
*/
public 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 is enabled in the underlying logger.
*/
public 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 is enabled in the underlying logger.
*/
public 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 is enabled in the underlying logger.
*/
public 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 is enabled in the underlying logger.
*/
public boolean isWarnEnabled();
// -------------------------------------------------------- Logging Methods
/**
* <p> Log a message with trace log level. </p>
*
* @param message log this message
*/
public void trace(Object message);
/**
* <p> Log an error with trace log level. </p>
*
* @param message log this message
* @param t log this cause
*/
public void trace(Object message, Throwable t);
/**
* <p> Log a message with debug log level. </p>
*
* @param message log this message
*/
public void debug(Object message);
/**
* <p> Log an error with debug log level. </p>
*
* @param message log this message
* @param t log this cause
*/
public void debug(Object message, Throwable t);
/**
* <p> Log a message with info log level. </p>
*
* @param message log this message
*/
public void info(Object message);
/**
* <p> Log an error with info log level. </p>
*
* @param message log this message
* @param t log this cause
*/
public void info(Object message, Throwable t);
/**
* <p> Log a message with warn log level. </p>
*
* @param message log this message
*/
public void warn(Object message);
/**
* <p> Log an error with warn log level. </p>
*
* @param message log this message
* @param t log this cause
*/
public void warn(Object message, Throwable t);
/**
* <p> Log a message with error log level. </p>
*
* @param message log this message
*/
public void error(Object message);
/**
* <p> Log an error with error log level. </p>
*
* @param message log this message
* @param t log this cause
*/
public void error(Object message, Throwable t);
/**
* <p> Log a message with fatal log level. </p>
*
* @param message log this message
*/
public void fatal(Object message);
/**
* <p> Log an error with fatal log level. </p>
*
* @param message log this message
* @param t log this cause
*/
public void fatal(Object message, Throwable t);
}