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.processor;
018
019import org.apache.camel.Exchange;
020import org.slf4j.Logger;
021
022import static org.apache.camel.util.ExchangeHelper.hasExceptionBeenHandledByErrorHandler;
023
024/**
025 * Helper for processing {@link org.apache.camel.Exchange} in a
026 * <a href="http://camel.apache.org/pipes-and-filters.html">pipeline</a>.
027 *
028 * @version 
029 */
030public final class PipelineHelper {
031
032    private PipelineHelper() {
033    }
034
035    /**
036     * Should we continue processing the exchange?
037     *
038     * @param exchange the next exchange
039     * @param message a message to use when logging that we should not continue processing
040     * @param log a logger
041     * @return <tt>true</tt> to continue processing, <tt>false</tt> to break out, for example if an exception occurred.
042     */
043    public static boolean continueProcessing(Exchange exchange, String message, Logger log) {
044        // check for error if so we should break out
045        boolean exceptionHandled = hasExceptionBeenHandledByErrorHandler(exchange);
046        if (exchange.isFailed() || exchange.isRollbackOnly() || exceptionHandled) {
047            // We need to write a warning message when the exception and fault message be set at the same time
048            if (exchange.hasOut() && exchange.getOut().isFault() && exchange.getException() != null) {
049                StringBuilder sb = new StringBuilder();
050                sb.append("Message exchange has failed: " + message + " for exchange: ").append(exchange);
051                sb.append(" Warning: Both fault and exception exists on the exchange, its best practice to only set one of them.");
052                sb.append(" Exception: ").append(exchange.getException());
053                sb.append(" Fault: ").append(exchange.getOut());
054                if (exceptionHandled) {
055                    sb.append(" Handled by the error handler.");
056                }
057                log.warn(sb.toString());
058            }
059            // The Exchange.ERRORHANDLED_HANDLED property is only set if satisfactory handling was done
060            // by the error handler. It's still an exception, the exchange still failed.
061            if (log.isDebugEnabled()) {
062                StringBuilder sb = new StringBuilder();
063                sb.append("Message exchange has failed: " + message + " for exchange: ").append(exchange);
064                if (exchange.isRollbackOnly()) {
065                    sb.append(" Marked as rollback only.");
066                }
067                if (exchange.getException() != null) {
068                    sb.append(" Exception: ").append(exchange.getException());
069                }
070                if (exchange.hasOut() && exchange.getOut().isFault()) {
071                    sb.append(" Fault: ").append(exchange.getOut());
072                }
073                if (exceptionHandled) {
074                    sb.append(" Handled by the error handler.");
075                }
076                log.debug(sb.toString());
077            }
078
079            return false;
080        }
081
082        // check for stop
083        Object stop = exchange.getProperty(Exchange.ROUTE_STOP);
084        if (stop != null) {
085            boolean doStop = exchange.getContext().getTypeConverter().convertTo(Boolean.class, exchange, stop);
086            if (doStop) {
087                log.debug("ExchangeId: {} is marked to stop routing: {}", exchange.getExchangeId(), exchange);
088                return false;
089            }
090        }
091
092        return true;
093    }
094
095    /**
096     * Strategy method to create the next exchange from the previous exchange.
097     * <p/>
098     * Remember to copy the original exchange id otherwise correlation of ids in the log is a problem
099     *
100     * @param previousExchange the previous exchange
101     * @return a new exchange
102     */
103    public static Exchange createNextExchange(Exchange previousExchange) {
104        Exchange answer = previousExchange;
105
106        // now lets set the input of the next exchange to the output of the
107        // previous message if it is not null
108        if (answer.hasOut()) {
109            answer.setIn(answer.getOut());
110            answer.setOut(null);
111        }
112        return answer;
113    }
114
115}