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     */
017    package org.apache.camel.processor.interceptor;
018    
019    import org.apache.camel.Exchange;
020    import org.apache.camel.Processor;
021    import org.apache.camel.model.ProcessorDefinition;
022    
023    /**
024     * A handler which reacts on trace events.
025     */
026    public interface TraceEventHandler {
027    
028        /**
029         * Event called when an {@link Exchange} is about to be processed
030         * <p/>
031         * This event is only called if trace out has been disabled (which it is by default).
032         * <p/>
033         * This method is for coarse grained tracing, where as the the other two methods is for fine grained
034         * with in and event events.
035         *
036         * @param node             the current node
037         * @param target           the current processor being invoked
038         * @param traceInterceptor the trace interceptor
039         * @param exchange         the current exchange
040         * @throws Exception is thrown if an error occurred during tracing
041         */
042        void traceExchange(ProcessorDefinition<?> node, Processor target, TraceInterceptor traceInterceptor, Exchange exchange) throws Exception;
043    
044        /**
045         * Event called when an {@link Exchange} is about to be processed (in)
046         * <p/>
047         * This event is only called if trace out has been enabled.
048         *
049         * @param node             the current node
050         * @param target           the current processor being invoked
051         * @param traceInterceptor the trace interceptor
052         * @param exchange         the current exchange
053         * @return an optional return object to pass in the <tt>traceEventOut</tt> method.
054         * @throws Exception is thrown if an error occurred during tracing
055         */
056        Object traceExchangeIn(ProcessorDefinition<?> node, Processor target, TraceInterceptor traceInterceptor, Exchange exchange) throws Exception;
057    
058        /**
059         * Event called when an {@link Exchange} has been processed (out)
060         * <p/>
061         * This event is only called if trace out has been enabled.
062         *
063         * @param node             the current node
064         * @param target           the current processor being invoked
065         * @param traceInterceptor the trace interceptor
066         * @param exchange         the current exchange (contains exception if the processing failed with an exception)
067         * @param traceState       the optional object which was returned from the <tt>traceEventIn</tt> method.
068         * @throws Exception is thrown if an error occurred during tracing
069         */
070        void traceExchangeOut(ProcessorDefinition<?> node, Processor target, TraceInterceptor traceInterceptor, Exchange exchange, Object traceState) throws Exception;
071    
072    }