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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  
22  /***
23   * <p><b>Currency Validation</b> and Conversion routines (<code>java.math.BigDecimal</code>).</p>
24   * 
25   * <p>This is one implementation of a currency validator that has the following features:</p>
26   *    <ul>
27   *       <li>It is <i>lenient</i> about the the presence of the <i>currency symbol</i></li>
28   *       <li>It converts the currency to a <code>java.math.BigDecimal</code></li>
29   *    </ul>
30   * 
31   * <p>However any of the <i>number</i> validators can be used for <i>currency</i> validation.
32   *    For example, if you wanted a <i>currency</i> validator that converts to a
33   *    <code>java.lang.Integer</code> then you can simply instantiate an
34   *    <code>IntegerValidator</code> with the appropriate <i>format type</i>:</p>
35   *    
36   *    <p><code>... = new IntegerValidator(false, IntegerValidator.CURRENCY_FORMAT);</code></p>
37   *
38   * <p>Pick the appropriate validator, depending on the type (e.g Float, Double, Integer, Long etc)
39   *    you want the currency converted to. One thing to note - only the CurrencyValidator
40   *    implements <i>lenient</i> behaviour regarding the currency symbol.</p>
41   * 
42   * @version $Revision: 478334 $ $Date: 2006-11-22 21:31:54 +0000 (Wed, 22 Nov 2006) $
43   * @since Validator 1.3.0
44   */
45  public class CurrencyValidator extends BigDecimalValidator {
46  
47      private static final CurrencyValidator VALIDATOR = new CurrencyValidator();
48  
49      /*** DecimalFormat's currency symbol */
50      private static final char CURRENCY_SYMBOL = '\u00A4';
51  
52      /***
53       * Return a singleton instance of this validator.
54       * @return A singleton instance of the CurrencyValidator.
55       */
56      public static BigDecimalValidator getInstance() {
57          return VALIDATOR;
58      }
59  
60      /***
61       * Construct a <i>strict</i> instance.
62       */
63      public CurrencyValidator() {
64          this(true, true);
65      }
66  
67      /***
68       * Construct an instance with the specified strict setting.
69       * 
70       * @param strict <code>true</code> if strict 
71       *        <code>Format</code> parsing should be used.
72       * @param allowFractions <code>true</code> if fractions are
73       *        allowed or <code>false</code> if integers only.
74       */
75      public CurrencyValidator(boolean strict, boolean allowFractions) {
76          super(strict, CURRENCY_FORMAT, allowFractions);
77      }
78  
79      /***
80       * <p>Parse the value with the specified <code>Format</code>.</p>
81       * 
82       * <p>This implementation is lenient whether the currency symbol
83       *    is present or not. The default <code>NumberFormat</code>
84       *    behaviour is for the parsing to "fail" if the currency
85       *    symbol is missing. This method re-parses with a format
86       *    without the currency symbol if it fails initially.</p>
87       * 
88       * @param value The value to be parsed.
89       * @param formatter The Format to parse the value with.
90       * @return The parsed value if valid or <code>null</code> if invalid.
91       */
92      protected Object parse(String value, Format formatter) {
93  
94          // Initial parse of the value
95          Object parsedValue = super.parse(value, formatter);
96          if (parsedValue != null || !(formatter instanceof DecimalFormat)) {
97              return parsedValue;
98          }
99  
100         // Re-parse using a pattern without the currency symbol
101         DecimalFormat decimalFormat = (DecimalFormat)formatter;
102         String pattern = decimalFormat.toPattern();
103         if (pattern.indexOf(CURRENCY_SYMBOL) >= 0) {
104             StringBuffer buffer = new StringBuffer(pattern.length());
105             for (int i = 0; i < pattern.length(); i++) {
106                 if (pattern.charAt(i) != CURRENCY_SYMBOL) {
107                     buffer.append(pattern.charAt(i));
108                 }
109             }
110             decimalFormat.applyPattern(buffer.toString());
111             parsedValue = super.parse(value, decimalFormat);
112         }
113         return parsedValue;
114     }
115 }