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 *      https://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;
021
022/**
023 * <p><strong>Currency Validation</strong> and Conversion routines ({@code java.math.BigDecimal}).</p>
024 *
025 * <p>This is one implementation of a currency validator that has the following features:</p>
026 *    <ul>
027 *       <li>It is <em>lenient</em> about the presence of the <em>currency symbol</em></li>
028 *       <li>It converts the currency to a {@code java.math.BigDecimal}</li>
029 *    </ul>
030 *
031 * <p>However any of the <em>number</em> validators can be used for <em>currency</em> validation.
032 *    For example, if you wanted a <em>currency</em> validator that converts to a
033 *    {@link Integer} then you can simply instantiate an
034 *    {@code IntegerValidator} with the appropriate <em>format type</em>:</p>
035 *
036 *    <p>{@code ... = new IntegerValidator(false, IntegerValidator.CURRENCY_FORMAT);}</p>
037 *
038 * <p>Pick the appropriate validator, depending on the type (for example, Float, Double, Integer, Long and so on)
039 *    you want the currency converted to. One thing to note - only the CurrencyValidator
040 *    implements <em>lenient</em> behavior regarding the currency symbol.</p>
041 *
042 * @since 1.3.0
043 */
044public class CurrencyValidator extends BigDecimalValidator {
045
046    private static final long serialVersionUID = -4201640771171486514L;
047
048    private static final CurrencyValidator VALIDATOR = new CurrencyValidator();
049
050    /** DecimalFormat's currency symbol */
051    private static final char CURRENCY_SYMBOL = '\u00A4';
052
053    /**
054     * Gets the singleton instance of this validator.
055     *
056     * @return A singleton instance of the CurrencyValidator.
057     */
058    public static BigDecimalValidator getInstance() {
059        return VALIDATOR;
060    }
061
062    /**
063     * Constructs a <em>strict</em> instance.
064     */
065    public CurrencyValidator() {
066        this(true, true);
067    }
068
069    /**
070     * Constructs an instance with the specified strict setting.
071     *
072     * @param strict {@code true} if strict
073     *        {@code Format} parsing should be used.
074     * @param allowFractions {@code true} if fractions are
075     *        allowed or {@code false} if integers only.
076     */
077    public CurrencyValidator(final boolean strict, final boolean allowFractions) {
078        super(strict, CURRENCY_FORMAT, allowFractions);
079    }
080
081    /**
082     * <p>Parse the value with the specified {@code Format}.</p>
083     *
084     * <p>This implementation is lenient whether the currency symbol
085     *    is present or not. The default {@code NumberFormat}
086     *    behavior is for the parsing to "fail" if the currency
087     *    symbol is missing. This method re-parses with a format
088     *    without the currency symbol if it fails initially.</p>
089     *
090     * @param value The value to be parsed.
091     * @param formatter The Format to parse the value with.
092     * @return The parsed value if valid or {@code null} if invalid.
093     */
094    @Override
095    protected Object parse(final String value, final Format formatter) {
096
097        // Initial parse of the value
098        Object parsedValue = super.parse(value, formatter);
099        if (parsedValue != null || !(formatter instanceof DecimalFormat)) {
100            return parsedValue;
101        }
102
103        // Re-parse using a pattern without the currency symbol
104        final DecimalFormat decimalFormat = (DecimalFormat) formatter;
105        final String pattern = decimalFormat.toPattern();
106        if (pattern.indexOf(CURRENCY_SYMBOL) >= 0) {
107            final StringBuilder buffer = new StringBuilder(pattern.length());
108            for (int i = 0; i < pattern.length(); i++) {
109                if (pattern.charAt(i) != CURRENCY_SYMBOL) {
110                    buffer.append(pattern.charAt(i));
111                }
112            }
113            decimalFormat.applyPattern(buffer.toString());
114            parsedValue = super.parse(value, decimalFormat);
115        }
116        return parsedValue;
117    }
118}