001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.camel.spi;
018
019import org.apache.camel.Exchange;
020import org.apache.camel.LoggingLevel;
021
022/**
023 * An event listener SPI for logging. Listeners are registered into {@link org.apache.camel.processor.LogProcessor} and
024 * {@link org.apache.camel.processor.CamelLogProcessor} so that the logging events are delivered for both of Log Component and Log EIP.
025 */
026public interface LogListener {
027
028    /**
029     * Invoked right before Log component or Log EIP logs.
030     * Note that {@link CamelLogger} holds the {@link LoggingLevel} and {@link org.slf4j.Marker}.
031     * The listener can check {@link CamelLogger#getLevel()} to see in which log level
032     * this is going to be logged.
033     * 
034     * @param exchange camel exchange
035     * @param camelLogger {@link CamelLogger}
036     * @param message log message
037     * @return log message, possibly enriched by the listener
038     */
039    String onLog(Exchange exchange, CamelLogger camelLogger, String message);
040
041}