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 }