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Java > Open Source Codes > org > apache > commons > beanutils > converters > DoubleArrayConverter


1 /*
2  * Copyright 2001-2004 The Apache Software Foundation.
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
18 package org.apache.commons.beanutils.converters;
19
20
21 import java.util.List JavaDoc;
22 import org.apache.commons.beanutils.ConversionException;
23 import org.apache.commons.beanutils.Converter;
24
25
26 /**
27  * <p>Standard {@link Converter} implementation that converts an incoming
28  * String into a primitive array of double. On a conversion failure, returns
29  * a specified default value or throws a {@link ConversionException} depending
30  * on how this instance is constructed.</p>
31  *
32  * @author Craig R. McClanahan
33  * @version $Revision: 1.7 $ $Date: 2004/02/28 13:18:34 $
34  * @since 1.4
35  */
36
37 public final class DoubleArrayConverter extends AbstractArrayConverter {
38
39
40     // ----------------------------------------------------------- Constructors
41
42
43     /**
44      * Create a {@link Converter} that will throw a {@link ConversionException}
45      * if a conversion error occurs.
46      */
47     public DoubleArrayConverter() {
48
49         this.defaultValue = null;
50         this.useDefault = false;
51
52     }
53
54
55     /**
56      * Create a {@link Converter} that will return the specified default value
57      * if a conversion error occurs.
58      *
59      * @param defaultValue The default value to be returned
60      */
61     public DoubleArrayConverter(Object JavaDoc defaultValue) {
62
63         this.defaultValue = defaultValue;
64         this.useDefault = true;
65
66     }
67
68
69     // ------------------------------------------------------- Static Variables
70
71
72     /**
73      * <p>Model object for type comparisons.</p>
74      */
75     private static double model[] = new double[0];
76
77
78     // --------------------------------------------------------- Public Methods
79
80
81     /**
82      * Convert the specified input object into an output object of the
83      * specified type.
84      *
85      * @param type Data type to which this value should be converted
86      * @param value The input value to be converted
87      *
88      * @exception ConversionException if conversion cannot be performed
89      * successfully
90      */
91     public Object JavaDoc convert(Class JavaDoc type, Object JavaDoc value) {
92
93         // Deal with a null value
94 if (value == null) {
95             if (useDefault) {
96                 return (defaultValue);
97             } else {
98                 throw new ConversionException("No value specified");
99             }
100         }
101
102         // Deal with the no-conversion-needed case
103 if (model.getClass() == value.getClass()) {
104             return (value);
105         }
106
107         // Deal with input value as a String array
108 if (strings.getClass() == value.getClass()) {
109             try {
110                 String JavaDoc values[] = (String JavaDoc[]) value;
111                 double results[] = new double[values.length];
112                 for (int i = 0; i < values.length; i++) {
113                     results[i] = Double.parseDouble(values[i]);
114                 }
115                 return (results);
116             } catch (Exception JavaDoc e) {
117                 if (useDefault) {
118                     return (defaultValue);
119                 } else {
120                     throw new ConversionException(value.toString(), e);
121                 }
122             }
123         }
124
125         // Parse the input value as a String into elements
126 // and convert to the appropriate type
127 try {
128             List JavaDoc list = parseElements(value.toString());
129             double results[] = new double[list.size()];
130             for (int i = 0; i < results.length; i++) {
131                 results[i] = Double.parseDouble((String JavaDoc) list.get(i));
132             }
133             return (results);
134         } catch (Exception JavaDoc e) {
135             if (useDefault) {
136                 return (defaultValue);
137             } else {
138                 throw new ConversionException(value.toString(), e);
139             }
140         }
141
142     }
143
144
145 }
146
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