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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.support;
18  
19  import java.util.ArrayList;
20  import java.util.List;
21  
22  import org.springframework.aop.support.AopUtils;
23  import org.springframework.batch.item.ItemReader;
24  
25  /**
26   * An {@link ItemReader} that pulls data from a list. Useful for testing.
27   * 
28   * @author Dave Syer
29   * 
30   */
31  public class ListItemReader<T> implements ItemReader<T> {
32  
33  	private List<T> list;
34  
35  	public ListItemReader(List<T> list) {
36  		// If it is a proxy we assume it knows how to deal with its own state.
37  		// (It's probably transaction aware.)
38  		if (AopUtils.isAopProxy(list)) {
39  			this.list = list;
40  		}
41  		else {
42  			this.list = new ArrayList<T>(list);
43  		}
44  	}
45  
46      @Override
47  	public T read() {
48  		if (!list.isEmpty()) {
49  			return list.remove(0);
50  		}
51  		return null;
52  	}
53  
54  }