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1   /*
2    * Copyright 2006-2007 the original author or authors.
3    *
4    * Licensed under the Apache License, Version 2.0 (the "License");
5    * you may not use this file except in compliance with the License.
6    * You may obtain a copy of the License at
7    *
8    *      http://www.apache.org/licenses/LICENSE-2.0
9    *
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS,
12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   * See the License for the specific language governing permissions and
14   * limitations under the License.
15   */
16  
17  package org.springframework.batch.item;
18  
19  /**
20   * Interface for item transformation.  Given an item as input, this interface provides
21   * an extension point which allows for the application of business logic in an item 
22   * oriented processing scenario.  It should be noted that while it's possible to return
23   * a different type than the one provided, it's not strictly necessary.  Furthermore, 
24   * returning null indicates that the item should not be continued to be processed.
25   *  
26   * @author Robert Kasanicky
27   * @author Dave Syer
28   */
29  public interface ItemProcessor<I, O> {
30  
31  	/**
32  	 * Process the provided item, returning a potentially modified or new item for continued
33  	 * processing.  If the returned result is null, it is assumed that processing of the item
34  	 * should not continue.
35  	 * 
36  	 * @param item to be processed
37  	 * @return potentially modified or new item for continued processing, null if processing of the 
38  	 *  provided item should not continue.
39  	 * @throws Exception
40  	 */
41  	O process(I item) throws Exception;
42  }