/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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;
/**
* 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>
* 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 implementation should ensure, though, that this ordering behaves
* as expected.
* <p>
* Performance is often a logging concern.
* By examining the appropriate property,
* a component can avoid expensive operations (producing information
* to be logged).
* <p>
* For example,
* <pre>
* if (log.isDebugEnabled()) {
* ... do something expensive ...
* log.debug(theResult);
* }
* </pre>
* <p>
* Configuration of the underlying logging system will generally be done
* external to the Logging APIs, through whatever mechanism is supported by
* that system.
*
* @version $Id: Log.java 1606045 2014-06-27 12:11:56Z tn $
*/
public interface Log {
/**
* Logs a message with debug log level.
*
* @param message log this message
*/
void debug(Object message);
/**
* Logs an error with debug log level.
*
* @param message log this message
* @param t log this cause
*/
void debug(Object message, Throwable t);
/**
* Logs a message with error log level.
*
* @param message log this message
*/
void error(Object message);
/**
* Logs an error with error log level.
*
* @param message log this message
* @param t log this cause
*/
void error(Object message, Throwable t);
/**
* Logs a message with fatal log level.
*
* @param message log this message
*/
void fatal(Object message);
/**
* Logs an error with fatal log level.
*
* @param message log this message
* @param t log this cause
*/
void fatal(Object message, Throwable t);
/**
* Logs a message with info log level.
*
* @param message log this message
*/
void info(Object message);
/**
* Logs an error with info log level.
*
* @param message log this message
* @param t log this cause
*/
void info(Object message, Throwable t);
/**
* Is debug logging currently enabled?
* <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.
*
* @return true if debug is enabled in the underlying logger.
*/
boolean isDebugEnabled();
/**
* Is error logging currently enabled?
* <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.
*
* @return true if error is enabled in the underlying logger.
*/
boolean isErrorEnabled();
/**
* Is fatal logging currently enabled?
* <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.
*
* @return true if fatal is enabled in the underlying logger.
*/
boolean isFatalEnabled();
/**
* Is info logging currently enabled?
* <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.
*
* @return true if info is enabled in the underlying logger.
*/
boolean isInfoEnabled();
/**
* Is trace logging currently enabled?
* <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.
*
* @return true if trace is enabled in the underlying logger.
*/
boolean isTraceEnabled();
/**
* Is warn logging currently enabled?
* <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.
*
* @return true if warn is enabled in the underlying logger.
*/
boolean isWarnEnabled();
/**
* Logs a message with trace log level.
*
* @param message log this message
*/
void trace(Object message);
/**
* Logs an error with trace log level.
*
* @param message log this message
* @param t log this cause
*/
void trace(Object message, Throwable t);
/**
* Logs a message with warn log level.
*
* @param message log this message
*/
void warn(Object message);
/**
* Logs an error with warn log level.
*
* @param message log this message
* @param t log this cause
*/
void warn(Object message, Throwable t);
}