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.math.BigDecimal;
020import java.text.DecimalFormat;
021import java.text.Format;
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 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 * @since 1.3.0
046 */
047public class PercentValidator extends BigDecimalValidator {
048
049    private static final long serialVersionUID = -3508241924961535772L;
050
051    private static final PercentValidator VALIDATOR = new PercentValidator();
052
053    /** DecimalFormat's percent (thousand multiplier) symbol */
054    private static final char PERCENT_SYMBOL = '%';
055
056    private static final BigDecimal POINT_ZERO_ONE = new BigDecimal("0.01");
057
058    /**
059     * Gets the singleton instance of this validator.
060     * @return A singleton instance of the PercentValidator.
061     */
062    public static BigDecimalValidator getInstance() {
063        return VALIDATOR;
064    }
065
066    /**
067     * Constructs a <i>strict</i> instance.
068     */
069    public PercentValidator() {
070        this(true);
071    }
072
073    /**
074     * Constructs an instance with the specified strict setting.
075     *
076     * @param strict {@code true} if strict
077     *        <code>Format</code> parsing should be used.
078     */
079    public PercentValidator(final boolean strict) {
080        super(strict, PERCENT_FORMAT, true);
081    }
082
083    /**
084     * <p>Parse the value with the specified <code>Format</code>.</p>
085     *
086     * <p>This implementation is lenient whether the currency symbol
087     *    is present or not. The default <code>NumberFormat</code>
088     *    behavior is for the parsing to "fail" if the currency
089     *    symbol is missing. This method re-parses with a format
090     *    without the currency symbol if it fails initially.</p>
091     *
092     * @param value The value to be parsed.
093     * @param formatter The Format to parse the value with.
094     * @return The parsed value if valid or {@code null} if invalid.
095     */
096    @Override
097    protected Object parse(final String value, final 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        final DecimalFormat decimalFormat = (DecimalFormat) formatter;
107        final String pattern = decimalFormat.toPattern();
108        if (pattern.indexOf(PERCENT_SYMBOL) >= 0) {
109            final StringBuilder buffer = new StringBuilder(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}