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Java > Open Source Codes > org > jfree > data > io > CSV


1 /* ===========================================================
2  * JFreeChart : a free chart library for the Java(tm) platform
3  * ===========================================================
4  *
5  * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
6  *
7  * Project Info: http://www.jfree.org/jfreechart/index.html
8  *
9  * This library is free software; you can redistribute it and/or modify it
10  * under the terms of the GNU Lesser General Public License as published by
11  * the Free Software Foundation; either version 2.1 of the License, or
12  * (at your option) any later version.
13  *
14  * This library is distributed in the hope that it will be useful, but
15  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
16  * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
17  * License for more details.
18  *
19  * You should have received a copy of the GNU Lesser General Public
20  * License along with this library; if not, write to the Free Software
21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
22  * USA.
23  *
24  * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
25  * in the United States and other countries.]
26  *
27  * --------
28  * CSV.java
29  * --------
30  * (C) Copyright 2003, 2004, by Object Refinery Limited.
31  *
32  * Original Author: David Gilbert (for Object Refinery Limited);
33  * Contributor(s): -;
34  *
35  * $Id: CSV.java,v 1.3.2.1 2005/10/25 21:33:38 mungady Exp $
36  *
37  * Changes
38  * -------
39  * 24-Nov-2003 : Version 1 (DG);
40  *
41  */
42
43 package org.jfree.data.io;
44
45 import java.io.BufferedReader JavaDoc;
46 import java.io.IOException JavaDoc;
47 import java.io.Reader JavaDoc;
48 import java.util.List JavaDoc;
49
50 import org.jfree.data.category.CategoryDataset;
51 import org.jfree.data.category.DefaultCategoryDataset;
52
53 /**
54  * A utility class for reading {@link CategoryDataset} data from a CSV file.
55  * This initial version is very basic, and won't handle errors in the data
56  * file very gracefully.
57  */
58 public class CSV {
59
60     /** The field delimiter. */
61     private char fieldDelimiter;
62     
63     /** The text delimiter. */
64     private char textDelimiter;
65      
66     /**
67      * Creates a new CSV reader where the field delimiter is a comma, and the
68      * text delimiter is a double-quote.
69      */
70     public CSV() {
71         this(',', '"');
72     }
73     
74     /**
75      * Creates a new reader with the specified field and text delimiters.
76      *
77      * @param fieldDelimiter the field delimiter (usually a comma, semi-colon,
78      * colon, tab or space).
79      * @param textDelimiter the text delimiter (usually a single or double
80      * quote).
81      */
82     public CSV(char fieldDelimiter, char textDelimiter) {
83         this.fieldDelimiter = fieldDelimiter;
84         this.textDelimiter = textDelimiter;
85     }
86     
87     /**
88      * Reads a {@link CategoryDataset} from a CSV file or input source.
89      *
90      * @param in the input source.
91      *
92      * @return A category dataset.
93      *
94      * @throws IOException if there is an I/O problem.
95      */
96     public CategoryDataset readCategoryDataset(Reader JavaDoc in) throws IOException JavaDoc {
97         
98         DefaultCategoryDataset dataset = new DefaultCategoryDataset();
99         BufferedReader JavaDoc reader = new BufferedReader JavaDoc(in);
100         List JavaDoc columnKeys = null;
101         int lineIndex = 0;
102         String JavaDoc line = reader.readLine();
103         while (line != null) {
104             if (lineIndex == 0) { // first line contains column keys
105 columnKeys = extractColumnKeys(line);
106             }
107             else { // remaining lines contain a row key and data values
108 extractRowKeyAndData(line, dataset, columnKeys);
109             }
110             line = reader.readLine();
111             lineIndex++;
112         }
113         return dataset;
114          
115     }
116     
117     /**
118      * Extracts the column keys from a string.
119      *
120      * @param line a line from the input file.
121      *
122      * @return A list of column keys.
123      */
124     private List JavaDoc extractColumnKeys(String JavaDoc line) {
125         List JavaDoc keys = new java.util.ArrayList JavaDoc();
126         int fieldIndex = 0;
127         int start = 0;
128         for (int i = 0; i < line.length(); i++) {
129             if (line.charAt(i) == this.fieldDelimiter) {
130                 if (fieldIndex > 0) { // first field is ignored, since
131 // column 0 is for row keys
132 String JavaDoc key = line.substring(start, i);
133                     keys.add(removeStringDelimiters(key));
134                 }
135                 start = i + 1;
136                 fieldIndex++;
137             }
138         }
139         String JavaDoc key = line.substring(start, line.length());
140         keys.add(removeStringDelimiters(key));
141         return keys;
142     }
143     
144     /**
145      * Extracts the row key and data for a single line from the input source.
146      *
147      * @param line the line from the input source.
148      * @param dataset the dataset to be populated.
149      * @param columnKeys the column keys.
150      */
151     private void extractRowKeyAndData(String JavaDoc line,
152                                       DefaultCategoryDataset dataset,
153                                       List JavaDoc columnKeys) {
154         Comparable JavaDoc rowKey = null;
155         int fieldIndex = 0;
156         int start = 0;
157         for (int i = 0; i < line.length(); i++) {
158             if (line.charAt(i) == this.fieldDelimiter) {
159                 if (fieldIndex == 0) { // first field contains the row key
160 String JavaDoc key = line.substring(start, i);
161                     rowKey = removeStringDelimiters(key);
162                 }
163                 else { // remaining fields contain values
164 Double JavaDoc value = Double.valueOf(
165                         removeStringDelimiters(line.substring(start, i))
166                     );
167                     dataset.addValue(
168                         value, rowKey,
169                         (Comparable JavaDoc) columnKeys.get(fieldIndex - 1)
170                     );
171                 }
172                 start = i + 1;
173                 fieldIndex++;
174             }
175         }
176         Double JavaDoc value = Double.valueOf(
177             removeStringDelimiters(line.substring(start, line.length()))
178         );
179         dataset.addValue(
180             value, rowKey, (Comparable JavaDoc) columnKeys.get(fieldIndex - 1)
181         );
182     }
183     
184     /**
185      * Removes the string delimiters from a key (as well as any white space
186      * outside the delimiters).
187      *
188      * @param key the key (including delimiters).
189      *
190      * @return The key without delimiters.
191      */
192     private String JavaDoc removeStringDelimiters(String JavaDoc key) {
193         String JavaDoc k = key.trim();
194         if (k.charAt(0) == this.textDelimiter) {
195             k = k.substring(1);
196         }
197         if (k.charAt(k.length() - 1) == this.textDelimiter) {
198             k = k.substring(0, k.length() - 1);
199         }
200         return k;
201     }
202     
203 }
204
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