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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   * <p>
21   * Marker interface defining a contract for periodically storing state and restoring from that state should an error
22   * occur.
23   * <p>
24   * 
25   * @author Dave Syer
26   * @author Lucas Ward
27   * 
28   */
29  public interface ItemStream {
30  
31  	/**
32  	 * Open the stream for the provided {@link ExecutionContext}.
33  	 * 
34  	 * @throws IllegalArgumentException if context is null
35  	 */
36  	void open(ExecutionContext executionContext) throws ItemStreamException;
37  
38  	/**
39  	 * Indicates that the execution context provided during open is about to be saved. If any state is remaining, but
40  	 * has not been put in the context, it should be added here.
41  	 * 
42  	 * @param executionContext to be updated
43  	 * @throws IllegalArgumentException if executionContext is null.
44  	 */
45  	void update(ExecutionContext executionContext) throws ItemStreamException;
46  
47  	/**
48  	 * If any resources are needed for the stream to operate they need to be destroyed here. Once this method has been
49  	 * called all other methods (except open) may throw an exception.
50  	 */
51  	void close() throws ItemStreamException;
52  }