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    1   /*
    2    * $Id: CurrencyValidator.java 386637 2006-03-17 13:22:26Z niallp $
    3    * $Revision: 386637 $
    4    * $Date: 2006-03-17 13:22:26 +0000 (Fri, 17 Mar 2006) $
    5    *
    6    * ====================================================================
    7    * Copyright 2006 The Apache Software Foundation
    8    *
    9    * Licensed under the Apache License, Version 2.0 (the "License");
    10   * you may not use this file except in compliance with the License.
    11   * You may obtain a copy of the License at
    12   *
    13   *     http://www.apache.org/licenses/LICENSE-2.0
    14   *
    15   * Unless required by applicable law or agreed to in writing, software
    16   * distributed under the License is distributed on an "AS IS" BASIS,
    17   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    18   * See the License for the specific language governing permissions and
    19   * limitations under the License.
    20   */
    21  package org.apache.commons.validator.routines;
    22
    23  import java.text.DecimalFormat;
    24  import java.text.Format;
    25
    26  /***
    27   * <p><b>Currency Validation</b> and Conversion routines (<code>java.math.BigDecimal</code>).</p>
    28   *
    29   * <p>This is one implementation of a currency validator that has the following features:</p>
    30   *    <ul>
    31   *       <li>It is <i>lenient</i> about the the presence of the <i>currency symbol</i></li>
    32   *       <li>It converts the currency to a <code>java.math.BigDecimal</code></li>
    33   *    </ul>
    34   *
    35   * <p>However any of the <i>number</i> validators can be used for <i>currency</i> validation.
    36   *    For example, if you wanted a <i>currency</i> validator that converts to a
    37   *    <code>java.lang.Integer</code> then you can simply instantiate an
    38   *    <code>IntegerValidator</code> with the appropriate <i>format type</i>:</p>
    39   *
    40   *    <p><code>... = new IntegerValidator(false, IntegerValidator.CURRENCY_FORMAT);</code></p>
    41   *
    42   * <p>Pick the appropriate validator, depending on the type (e.g Float, Double, Integer, Long etc)
    43   *    you want the currency converted to. One thing to note - only the CurrencyValidator
    44   *    implements <i>lenient</i> behaviour regarding the currency symbol.</p>
    45   *
    46   * @version $Revision: 386637 $ $Date: 2006-03-17 13:22:26 +0000 (Fri, 17 Mar 2006) $
    47   * @since Validator 1.3.0
    48   */
    49  public class CurrencyValidator extends BigDecimalValidator {
    50
    51      private static final CurrencyValidator VALIDATOR = new CurrencyValidator();
    52
    53      /*** DecimalFormat's currency symbol */
    54      private static final char CURRENCY_SYMBOL = '\u00A4';
    55
    56      /***
    57       * Return a singleton instance of this validator.
    58       * @return A singleton instance of the CurrencyValidator.
    59       */
    60      public static BigDecimalValidator getInstance() {
    61          return VALIDATOR;
    62      }
    63
    64      /***
    65       * Construct a <i>strict</i> instance.
    66       */
    67      public CurrencyValidator() {
    68          this(true, true);
    69      }
    70
    71      /***
    72       * Construct an instance with the specified strict setting.
    73       *
    74       * @param strict <code>true</code> if strict
    75       *        <code>Format</code> parsing should be used.
    76       * @param allowFractions <code>true</code> if fractions are
    77       *        allowed or <code>false</code> if integers only.
    78       */
    79      public CurrencyValidator(boolean strict, boolean allowFractions) {
    80          super(strict, CURRENCY_FORMAT, allowFractions);
    81      }
    82
    83      /***
    84       * <p>Parse the value with the specified <code>Format</code>.</p>
    85       *
    86       * <p>This implementation is lenient whether the currency symbol
    87       *    is present or not. The default <code>NumberFormat</code>
    88       *    behaviour is for the parsing to "fail" if the currency
    89       *    symbol is missing. This method re-parses with a format
    90       *    without the currency symbol if it fails initially.</p>
    91       *
    92       * @param value The value to be parsed.
    93       * @param formatter The Format to parse the value with.
    94       * @return The parsed value if valid or <code>null</code> if invalid.
    95       */
    96      protected Object parse(String value, Format formatter) {
    97
    98          // Initial parse of the value
    99          Object parsedValue = super.parse(value, formatter);
    100         if (parsedValue != null || !(formatter instanceof DecimalFormat)) {
    101             return parsedValue;
    102         }
    103
    104         // Re-parse using a pattern without the currency symbol
    105         DecimalFormat decimalFormat = (DecimalFormat)formatter;
    106         String pattern = decimalFormat.toPattern();
    107         if (pattern.indexOf(CURRENCY_SYMBOL) >= 0) {
    108             StringBuffer buffer = new StringBuffer(pattern.length());
    109             for (int i = 0; i < pattern.length(); i++) {
    110                 if (pattern.charAt(i) != CURRENCY_SYMBOL) {
    111                     buffer.append(pattern.charAt(i));
    112                 }
    113             }
    114             decimalFormat.applyPattern(buffer.toString());
    115             parsedValue = super.parse(value, decimalFormat);
    116         }
    117         return parsedValue;
    118     }
    119 }