001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.commons.validator.routines;
018
019import java.text.DecimalFormat;
020import java.text.Format;
021import java.math.BigDecimal;
022
023/**
024 * <p><b>Percentage Validation</b> and Conversion routines (<code>java.math.BigDecimal</code>).</p>
025 *
026 * <p>This is one implementation of a percent validator that has the following features:</p>
027 *    <ul>
028 *       <li>It is <i>lenient</i> about the the presence of the <i>percent symbol</i></li>
029 *       <li>It converts the percent to a <code>java.math.BigDecimal</code></li>
030 *    </ul>
031 *
032 * <p>However any of the <i>number</i> validators can be used for <i>percent</i> validation.
033 *    For example, if you wanted a <i>percent</i> validator that converts to a
034 *    <code>java.lang.Float</code> then you can simply instantiate an
035 *    <code>FloatValidator</code> with the appropriate <i>format type</i>:</p>
036 *
037 *    <p><code>... = new FloatValidator(false, FloatValidator.PERCENT_FORMAT);</code></p>
038 *
039 * <p>Pick the appropriate validator, depending on the type (i.e Float, Double or BigDecimal)
040 *    you want the percent converted to. Please note, it makes no sense to use
041 *    one of the validators that doesn't handle fractions (i.e. byte, short, integer, long
042 *    and BigInteger) since percentages are converted to fractions (i.e <code>50%</code> is
043 *    converted to <code>0.5</code>).</p>
044 *
045 * @version $Revision: 1227719 $ $Date: 2012-01-05 18:45:51 +0100 (Do, 05 Jan 2012) $
046 * @since Validator 1.3.0
047 */
048public class PercentValidator extends BigDecimalValidator {
049
050    private static final long serialVersionUID = -3508241924961535772L;
051
052    private static final PercentValidator VALIDATOR = new PercentValidator();
053
054    /** DecimalFormat's percent (thousand multiplier) symbol */
055    private static final char PERCENT_SYMBOL = '%';
056
057    private static final BigDecimal POINT_ZERO_ONE = new BigDecimal("0.01");
058
059    /**
060     * Return a singleton instance of this validator.
061     * @return A singleton instance of the PercentValidator.
062     */
063    public static BigDecimalValidator getInstance() {
064        return VALIDATOR;
065    }
066
067    /**
068     * Construct a <i>strict</i> instance.
069     */
070    public PercentValidator() {
071        this(true);
072    }
073
074    /**
075     * Construct an instance with the specified strict setting.
076     *
077     * @param strict <code>true</code> if strict
078     *        <code>Format</code> parsing should be used.
079     */
080    public PercentValidator(boolean strict) {
081        super(strict, PERCENT_FORMAT, true);
082    }
083
084    /**
085     * <p>Parse the value with the specified <code>Format</code>.</p>
086     *
087     * <p>This implementation is lenient whether the currency symbol
088     *    is present or not. The default <code>NumberFormat</code>
089     *    behaviour is for the parsing to "fail" if the currency
090     *    symbol is missing. This method re-parses with a format
091     *    without the currency symbol if it fails initially.</p>
092     *
093     * @param value The value to be parsed.
094     * @param formatter The Format to parse the value with.
095     * @return The parsed value if valid or <code>null</code> if invalid.
096     */
097    protected Object parse(String value, Format formatter) {
098
099        // Initial parse of the value
100        BigDecimal parsedValue = (BigDecimal)super.parse(value, formatter);
101        if (parsedValue != null || !(formatter instanceof DecimalFormat)) {
102            return parsedValue;
103        }
104
105        // Re-parse using a pattern without the percent symbol
106        DecimalFormat decimalFormat = (DecimalFormat)formatter;
107        String pattern = decimalFormat.toPattern();
108        if (pattern.indexOf(PERCENT_SYMBOL) >= 0) {
109            StringBuffer buffer = new StringBuffer(pattern.length());
110            for (int i = 0; i < pattern.length(); i++) {
111                if (pattern.charAt(i) != PERCENT_SYMBOL) {
112                    buffer.append(pattern.charAt(i));
113                }
114            }
115            decimalFormat.applyPattern(buffer.toString());
116            parsedValue = (BigDecimal)super.parse(value, decimalFormat);
117
118            // If parsed OK, divide by 100 to get percent
119            if (parsedValue != null) {
120                parsedValue = parsedValue.multiply(POINT_ZERO_ONE);
121            }
122
123        }
124        return parsedValue;
125    }
126}