001package org.eclipse.aether.spi.log;
002
003/*
004 * Licensed to the Apache Software Foundation (ASF) under one
005 * or more contributor license agreements.  See the NOTICE file
006 * distributed with this work for additional information
007 * regarding copyright ownership.  The ASF licenses this file
008 * to you under the Apache License, Version 2.0 (the
009 * "License"); you may not use this file except in compliance
010 * with the License.  You may obtain a copy of the License at
011 * 
012 *  http://www.apache.org/licenses/LICENSE-2.0
013 * 
014 * Unless required by applicable law or agreed to in writing,
015 * software distributed under the License is distributed on an
016 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
017 * KIND, either express or implied.  See the License for the
018 * specific language governing permissions and limitations
019 * under the License.
020 */
021
022/**
023 * A simple logger to facilitate emission of diagnostic messages. In general, unrecoverable errors should be reported
024 * via exceptions and informational notifications should be reported via events, hence this logger interface focuses on
025 * support for tracing.
026 */
027public interface Logger
028{
029
030    /**
031     * Indicates whether debug logging is enabled.
032     * 
033     * @return {@code true} if debug logging is enabled, {@code false} otherwise.
034     */
035    boolean isDebugEnabled();
036
037    /**
038     * Emits the specified message.
039     * 
040     * @param msg The message to log, must not be {@code null}.
041     */
042    void debug( String msg );
043
044    /**
045     * Emits the specified message along with a stack trace of the given exception.
046     * 
047     * @param msg The message to log, must not be {@code null}.
048     * @param error The exception to log, may be {@code null}.
049     */
050    void debug( String msg, Throwable error );
051
052    /**
053     * Indicates whether warn logging is enabled.
054     * 
055     * @return {@code true} if warn logging is enabled, {@code false} otherwise.
056     */
057    boolean isWarnEnabled();
058
059    /**
060     * Emits the specified message.
061     * 
062     * @param msg The message to log, must not be {@code null}.
063     */
064    void warn( String msg );
065
066    /**
067     * Emits the specified message along with a stack trace of the given exception.
068     * 
069     * @param msg The message to log, must not be {@code null}.
070     * @param error The exception to log, may be {@code null}.
071     */
072    void warn( String msg, Throwable error );
073
074}