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;
018    
019    /**
020     * Strategy for a {@link org.apache.camel.PollingConsumer} when polling an {@link org.apache.camel.Endpoint}.
021     * <p/>
022     * This pluggable strategy allows to plugin different implementations what to do, most noticeable what to
023     * do in case the polling goes wrong. This can be handled in the {@link #rollback(Consumer, Endpoint, int, Exception) rollback}
024     * method.
025     *
026     * @version $Revision: 789216 $
027     */
028    public interface PollingConsumerPollStrategy {
029    
030        /**
031         * Called when poll is about to begin
032         *
033         * @param consumer the consumer
034         * @param endpoint the endpoint being consumed
035         */
036        void begin(Consumer consumer, Endpoint endpoint);
037    
038        /**
039         * Called when poll is completed successfully
040         *
041         * @param consumer the consumer
042         * @param endpoint the endpoint being consumed
043         */
044        void commit(Consumer consumer, Endpoint endpoint);
045    
046        /**
047         * Called when poll failed
048         *
049         * @param consumer the consumer
050         * @param endpoint the endpoint being consumed
051         * @param retryCounter current retry attempt, starting from 0.
052         * @param cause the caused exception
053         * @throws Exception can be used to rethrow the caused exception. Notice that thrown an exception will
054         *         terminate the scheduler and thus Camel will not trigger again. So if you want to let the scheduler
055         *         to continue to run then do <b>not</b> throw any exception from this method.
056         * @return whether to retry immediately or not. Return <tt>false</tt> to ignore the problem,
057         *         <tt>true</tt> to try immediately again
058         */
059        boolean rollback(Consumer consumer, Endpoint endpoint, int retryCounter, Exception cause) throws Exception;
060    
061    }