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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  /**
24   * Tokenizer used to process data obtained from files with fixed-length format.
25   * Columns are specified by array of Range objects ({@link #setColumns(Range[])}
26   * ).
27   * 
28   * @author tomas.slanina
29   * @author peter.zozom
30   * @author Dave Syer
31   * @author Lucas Ward
32   */
33  public class FixedLengthTokenizer extends AbstractLineTokenizer {
34  
35  	private Range[] ranges;
36  
37  	private int maxRange = 0;
38  
39  	boolean open = false;
40  
41  	/**
42  	 * Set the column ranges. Used in conjunction with the
43  	 * {@link RangeArrayPropertyEditor} this property can be set in the form of
44  	 * a String describing the range boundaries, e.g. "1,4,7" or "1-3,4-6,7" or
45  	 * "1-2,4-5,7-10". If the last range is open then the rest of the line is
46  	 * read into that column (irrespective of the strict flag setting).
47  	 * 
48  	 * @see #setStrict(boolean)
49  	 * 
50  	 * @param ranges the column ranges expected in the input
51  	 */
52  	public void setColumns(Range[] ranges) {
53  		this.ranges = Arrays.asList(ranges).toArray(new Range[ranges.length]);
54  		calculateMaxRange(ranges);
55  	}
56  
57  	/*
58  	 * Calculate the highest value within an array of ranges. The ranges aren't
59  	 * necessarily in order. For example: "5-10, 1-4,11-15". Furthermore, there
60  	 * isn't always a min and max, such as: "1,4-20, 22"
61  	 */
62  	private void calculateMaxRange(Range[] ranges) {
63  		if (ranges == null || ranges.length == 0) {
64  			maxRange = 0;
65  			return;
66  		}
67  
68  		open = false;
69  		maxRange = ranges[0].getMin();
70  
71  		for (int i = 0; i < ranges.length; i++) {
72  			int upperBound;
73  			if (ranges[i].hasMaxValue()) {
74  				upperBound = ranges[i].getMax();
75  			}
76  			else {
77  				upperBound = ranges[i].getMin();
78  				if (upperBound > maxRange) {
79  					open = true;
80  				}
81  			}
82  
83  			if (upperBound > maxRange) {
84  				maxRange = upperBound;
85  			}
86  		}
87  	}
88  
89  	/**
90  	 * Yields the tokens resulting from the splitting of the supplied
91  	 * <code>line</code>.
92  	 * 
93  	 * @param line the line to be tokenised (can be <code>null</code>)
94  	 * 
95  	 * @return the resulting tokens (empty if the line is null)
96  	 * @throws IncorrectLineLengthException if line length is greater than or
97  	 * less than the max range set.
98  	 */
99      @Override
100 	protected List<String> doTokenize(String line) {
101 		List<String> tokens = new ArrayList<String>(ranges.length);
102 		int lineLength;
103 		String token;
104 
105 		lineLength = line.length();
106 
107 		if (lineLength < maxRange && isStrict()) {
108 			throw new IncorrectLineLengthException("Line is shorter than max range " + maxRange, maxRange, lineLength);
109 		}
110 
111 		if (!open && lineLength > maxRange && isStrict()) {
112 			throw new IncorrectLineLengthException("Line is longer than max range " + maxRange, maxRange, lineLength);
113 		}
114 
115 		for (int i = 0; i < ranges.length; i++) {
116 
117 			int startPos = ranges[i].getMin() - 1;
118 			int endPos = ranges[i].getMax();
119 
120 			if (lineLength >= endPos) {
121 				token = line.substring(startPos, endPos);
122 			}
123 			else if (lineLength >= startPos) {
124 				token = line.substring(startPos);
125 			}
126 			else {
127 				token = "";
128 			}
129 
130 			tokens.add(token);
131 		}
132 
133 		return tokens;
134 	}
135 }