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.component.file;
018
019 import org.apache.camel.Exchange;
020
021 /**
022 * Represents a pluggable strategy when processing files.
023 */
024 public interface GenericFileProcessStrategy<T> {
025
026 /**
027 * Allows custom logic to be run on first poll preparing the strategy,
028 * such as removing old lock files etc.
029 *
030 * @param operations file operations
031 * @param endpoint the endpoint
032 * @throws Exception can be thrown in case of errors which causes poll to fail
033 */
034 void prepareOnStartup(GenericFileOperations<T> operations, GenericFileEndpoint<T> endpoint) throws Exception;
035
036 /**
037 * Called when work is about to begin on this file. This method may attempt
038 * to acquire some file lock before returning true; returning false if the
039 * file lock could not be obtained so that the file should be ignored.
040 *
041 * @param operations file operations
042 * @param endpoint the endpoint
043 * @param exchange the exchange
044 * @param file the file
045 * @return true if the file can be processed (such as if a file lock could be obtained)
046 * @throws Exception can be thrown in case of errors
047 */
048 boolean begin(GenericFileOperations<T> operations, GenericFileEndpoint<T> endpoint,
049 Exchange exchange, GenericFile<T> file) throws Exception;
050
051 /**
052 * Called when a begin is aborted, for example to release any resources which may have
053 * been acquired during the {@link #begin(GenericFileOperations, GenericFileEndpoint, org.apache.camel.Exchange, GenericFile)}
054 * operation.
055 *
056 * @param operations file operations
057 * @param endpoint the endpoint
058 * @param exchange the exchange
059 * @param file the file
060 * @throws Exception can be thrown in case of errors
061 */
062 void abort(GenericFileOperations<T> operations, GenericFileEndpoint<T> endpoint,
063 Exchange exchange, GenericFile<T> file) throws Exception;
064
065 /**
066 * Releases any file locks and possibly deletes or moves the file after
067 * successful processing
068 *
069 * @param operations file operations
070 * @param endpoint the endpoint
071 * @param exchange the exchange
072 * @param file the file
073 * @throws Exception can be thrown in case of errors
074 */
075 void commit(GenericFileOperations<T> operations, GenericFileEndpoint<T> endpoint,
076 Exchange exchange, GenericFile<T> file) throws Exception;
077
078 /**
079 * Releases any file locks and possibly deletes or moves the file after
080 * unsuccessful processing
081 *
082 * @param operations file operations
083 * @param endpoint the endpoint
084 * @param exchange the exchange
085 * @param file the file
086 * @throws Exception can be thrown in case of errors
087 */
088 void rollback(GenericFileOperations<T> operations, GenericFileEndpoint<T> endpoint,
089 Exchange exchange, GenericFile<T> file) throws Exception;
090
091 }