    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     * Return a 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</code> 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}