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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.file.transform;
18  
19  import java.util.ArrayList;
20  import java.util.Arrays;
21  import java.util.List;
22  
23  import org.springframework.beans.BeanWrapper;
24  import org.springframework.beans.BeanWrapperImpl;
25  import org.springframework.beans.factory.InitializingBean;
26  import org.springframework.util.Assert;
27  
28  /**
29   * This is a field extractor for a java bean. Given an array of property names,
30   * it will reflectively call getters on the item and return an array of all the
31   * values.
32   * 
33   * @author Dan Garrette
34   * @since 2.0
35   */
36  public class BeanWrapperFieldExtractor<T> implements FieldExtractor<T>, InitializingBean {
37  
38  	private String[] names;
39  
40  	/**
41  	 * @param names field names to be extracted by the {@link #extract(Object)} method.
42  	 */
43  	public void setNames(String[] names) {
44  		Assert.notNull(names, "Names must be non-null");
45  		this.names = Arrays.asList(names).toArray(new String[names.length]);
46  	}
47  
48  	/**
49  	 * @see org.springframework.batch.item.file.transform.FieldExtractor#extract(java.lang.Object)
50  	 */
51      @Override
52  	public Object[] extract(T item) {
53  		List<Object> values = new ArrayList<Object>();
54  
55  		BeanWrapper bw = new BeanWrapperImpl(item);
56  		for (String propertyName : this.names) {
57  			values.add(bw.getPropertyValue(propertyName));
58  		}
59  		return values.toArray();
60  	}
61  
62      @Override
63  	public void afterPropertiesSet() {
64  		Assert.notNull(names, "The 'names' property must be set.");
65  	}
66  }