/*

  * Licensed to the Apache Software Foundation (ASF) under one or more

  * contributor license agreements.  See the NOTICE file distributed with

  * this work for additional information regarding copyright ownership.

  * The ASF licenses this file to You under the Apache License, Version 2.0

  * (the "License"); you may not use this file except in compliance with

  * the License.  You may obtain a copy of the License at

  *

  *      http://www.apache.org/licenses/LICENSE-2.0

  *

  * Unless required by applicable law or agreed to in writing, software

  * distributed under the License is distributed on an "AS IS" BASIS,

  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

  * See the License for the specific language governing permissions and

  * limitations under the License.

  */

 package org.apache.commons.validator.routines;

 import java.text.DecimalFormat;

 import java.text.Format;

 import java.math.BigDecimal;

 /**

  * <p><b>Percentage Validation</b> and Conversion routines (<code>java.math.BigDecimal</code>).</p>

  *

  * <p>This is one implementation of a percent validator that has the following features:</p>

  *    <ul>

  *       <li>It is <i>lenient</i> about the the presence of the <i>percent symbol</i></li>

  *       <li>It converts the percent to a <code>java.math.BigDecimal</code></li>

  *    </ul>

  *

  * <p>However any of the <i>number</i> validators can be used for <i>percent</i> validation.

  *    For example, if you wanted a <i>percent</i> validator that converts to a

  *    <code>java.lang.Float</code> then you can simply instantiate an

  *    <code>FloatValidator</code> with the appropriate <i>format type</i>:</p>

  *

  *    <p><code>... = new FloatValidator(false, FloatValidator.PERCENT_FORMAT);</code></p>

  *

  * <p>Pick the appropriate validator, depending on the type (i.e Float, Double or BigDecimal)

  *    you want the percent converted to. Please note, it makes no sense to use

  *    one of the validators that doesn't handle fractions (i.e. byte, short, integer, long

  *    and BigInteger) since percentages are converted to fractions (i.e <code>50%</code> is

  *    converted to <code>0.5</code>).</p>

  *

  * @version $Revision: 1739356 $

  * @since Validator 1.3.0

  */

 public class PercentValidator extends BigDecimalValidator {

     private static final long serialVersionUID = -3508241924961535772L;

     private static final PercentValidator VALIDATOR = new PercentValidator();

     /** DecimalFormat's percent (thousand multiplier) symbol */

     private static final char PERCENT_SYMBOL = '%';

     private static final BigDecimal POINT_ZERO_ONE = new BigDecimal("0.01");

     /**

      * Return a singleton instance of this validator.

      * @return A singleton instance of the PercentValidator.

      */

     public static BigDecimalValidator getInstance() {

         return VALIDATOR;

     }

     /**

      * Construct a <i>strict</i> instance.

      */

     public PercentValidator() {

         this(true);

     }

     /**

      * Construct an instance with the specified strict setting.

      *

      * @param strict <code>true</code> if strict

      *        <code>Format</code> parsing should be used.

      */

     public PercentValidator(boolean strict) {

         super(strict, PERCENT_FORMAT, true);

     }

     /**

      * <p>Parse the value with the specified <code>Format</code>.</p>

      *

      * <p>This implementation is lenient whether the currency symbol

      *    is present or not. The default <code>NumberFormat</code>

      *    behaviour is for the parsing to "fail" if the currency

      *    symbol is missing. This method re-parses with a format

      *    without the currency symbol if it fails initially.</p>

      *

      * @param value The value to be parsed.

      * @param formatter The Format to parse the value with.

      * @return The parsed value if valid or <code>null</code> if invalid.

      */

     @Override

     protected Object parse(String value, Format formatter) {

         // Initial parse of the value

         BigDecimal parsedValue = (BigDecimal)super.parse(value, formatter);

         if (parsedValue != null || !(formatter instanceof DecimalFormat)) {

             return parsedValue;

         }

         // Re-parse using a pattern without the percent symbol

         DecimalFormat decimalFormat = (DecimalFormat)formatter;

         String pattern = decimalFormat.toPattern();

         if (pattern.indexOf(PERCENT_SYMBOL) >= 0) {

             StringBuilder buffer = new StringBuilder(pattern.length());

             for (int i = 0; i < pattern.length(); i++) {

                 if (pattern.charAt(i) != PERCENT_SYMBOL) {

                     buffer.append(pattern.charAt(i));

                 }

             }

             decimalFormat.applyPattern(buffer.toString());

             parsedValue = (BigDecimal)super.parse(value, decimalFormat);

             // If parsed OK, divide by 100 to get percent

             if (parsedValue != null) {

                 parsedValue = parsedValue.multiply(POINT_ZERO_ONE);

             }

         }

         return parsedValue;

     }

 }