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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.Formatter;
20  import java.util.Locale;
21  
22  import org.springframework.util.Assert;
23  
24  /**
25   * A {@link LineAggregator} implementation which produces a String by
26   * aggregating the provided item via the {@link Formatter} syntax.</br>
27   * 
28   * @see Formatter
29   * 
30   * @author Dave Syer
31   */
32  public class FormatterLineAggregator<T> extends ExtractorLineAggregator<T> {
33  
34  	private String format;
35  
36  	private Locale locale = Locale.getDefault();
37  
38  	private int maximumLength = 0;
39  
40  	private int minimumLength = 0;
41  
42  	/**
43  	 * Public setter for the minimum length of the formatted string. If this is
44  	 * not set the default is to allow any length.
45  	 * 
46  	 * @param minimumLength the minimum length to set
47  	 */
48  	public void setMinimumLength(int minimumLength) {
49  		this.minimumLength = minimumLength;
50  	}
51  
52  	/**
53  	 * Public setter for the maximum length of the formatted string. If this is
54  	 * not set the default is to allow any length.
55  	 * @param maximumLength the maximum length to set
56  	 */
57  	public void setMaximumLength(int maximumLength) {
58  		this.maximumLength = maximumLength;
59  	}
60  
61  	/**
62  	 * Set the format string used to aggregate items.
63  	 * 
64  	 * @see Formatter
65  	 */
66  	public void setFormat(String format) {
67  		this.format = format;
68  	}
69  
70  	/**
71  	 * Public setter for the locale.
72  	 * @param locale the locale to set
73  	 */
74  	public void setLocale(Locale locale) {
75  		this.locale = locale;
76  	}
77  
78  	@Override
79  	protected String doAggregate(Object[] fields) {
80  
81  		Assert.notNull(format);
82  
83  		String value = String.format(locale, format, fields);
84  
85  		if (maximumLength > 0) {
86  			Assert.state(value.length() <= maximumLength, String.format("String overflowed in formatter -"
87  					+ " longer than %d characters: [%s", maximumLength, value));
88  		}
89  
90  		if (minimumLength > 0) {
91  			Assert.state(value.length() >= minimumLength, String.format("String underflowed in formatter -"
92  					+ " shorter than %d characters: [%s", minimumLength, value));
93  		}
94  
95  		return value;
96  	}
97  }