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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    *      http://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  package org.apache.commons.validator.routines;
18  
19  import java.text.DecimalFormat;
20  import java.text.Format;
21  import java.math.BigDecimal;
22  
23  /***
24   * <p><b>Percentage Validation</b> and Conversion routines (<code>java.math.BigDecimal</code>).</p>
25   * 
26   * <p>This is one implementation of a percent validator that has the following features:</p>
27   *    <ul>
28   *       <li>It is <i>lenient</i> about the the presence of the <i>percent symbol</i></li>
29   *       <li>It converts the percent to a <code>java.math.BigDecimal</code></li>
30   *    </ul>
31   * 
32   * <p>However any of the <i>number</i> validators can be used for <i>percent</i> validation.
33   *    For example, if you wanted a <i>percent</i> validator that converts to a
34   *    <code>java.lang.Float</code> then you can simply instantiate an
35   *    <code>FloatValidator</code> with the appropriate <i>format type</i>:</p>
36   *    
37   *    <p><code>... = new FloatValidator(false, FloatValidator.PERCENT_FORMAT);</code></p>
38   *
39   * <p>Pick the appropriate validator, depending on the type (i.e Float, Double or BigDecimal)
40   *    you want the percent converted to. Please note, it makes no sense to use
41   *    one of the validators that doesn't handle fractions (i.e. byte, short, integer, long
42   *    and BigInteger) since percentages are converted to fractions (i.e <code>50%</code> is
43   *    converted to <code>0.5</code>).</p>
44   *
45   * @version $Revision: 478334 $ $Date: 2006-11-22 21:31:54 +0000 (Wed, 22 Nov 2006) $
46   * @since Validator 1.3.0
47   */
48  public class PercentValidator extends BigDecimalValidator {
49  
50      private static final PercentValidator VALIDATOR = new PercentValidator();
51  
52      /*** DecimalFormat's percent (thousand multiplier) symbol */
53      private static final char PERCENT_SYMBOL = '%';
54  
55      private static final BigDecimal POINT_ZERO_ONE = new BigDecimal("0.01");
56  
57      /***
58       * Return a singleton instance of this validator.
59       * @return A singleton instance of the PercentValidator.
60       */
61      public static BigDecimalValidator getInstance() {
62          return VALIDATOR;
63      }
64  
65      /***
66       * Construct a <i>strict</i> instance.
67       */
68      public PercentValidator() {
69          this(true);
70      }
71  
72      /***
73       * Construct an instance with the specified strict setting.
74       * 
75       * @param strict <code>true</code> if strict 
76       *        <code>Format</code> parsing should be used.
77       */
78      public PercentValidator(boolean strict) {
79          super(strict, PERCENT_FORMAT, true);
80      }
81  
82      /***
83       * <p>Parse the value with the specified <code>Format</code>.</p>
84       * 
85       * <p>This implementation is lenient whether the currency symbol
86       *    is present or not. The default <code>NumberFormat</code>
87       *    behaviour is for the parsing to "fail" if the currency
88       *    symbol is missing. This method re-parses with a format
89       *    without the currency symbol if it fails initially.</p>
90       * 
91       * @param value The value to be parsed.
92       * @param formatter The Format to parse the value with.
93       * @return The parsed value if valid or <code>null</code> if invalid.
94       */
95      protected Object parse(String value, Format formatter) {
96  
97          // Initial parse of the value
98          BigDecimal parsedValue = (BigDecimal)super.parse(value, formatter);
99          if (parsedValue != null || !(formatter instanceof DecimalFormat)) {
100             return parsedValue;
101         }
102 
103         // Re-parse using a pattern without the percent symbol
104         DecimalFormat decimalFormat = (DecimalFormat)formatter;
105         String pattern = decimalFormat.toPattern();
106         if (pattern.indexOf(PERCENT_SYMBOL) >= 0) {
107             StringBuffer buffer = new StringBuffer(pattern.length());
108             for (int i = 0; i < pattern.length(); i++) {
109                 if (pattern.charAt(i) != PERCENT_SYMBOL) {
110                     buffer.append(pattern.charAt(i));
111                 }
112             }
113             decimalFormat.applyPattern(buffer.toString());
114             parsedValue = (BigDecimal)super.parse(value, decimalFormat);
115             
116             // If parsed OK, divide by 100 to get percent
117             if (parsedValue != null) {
118                 parsedValue = parsedValue.multiply(POINT_ZERO_ONE);
119             }
120             
121         }
122         return parsedValue;
123     }
124 }