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 */
017 package org.apache.commons.validator.routines;
018
019 import java.text.DecimalFormat;
020 import java.text.Format;
021 import 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: 493905 $ $Date: 2007-01-08 03:11:38 +0100 (Mo, 08. Jan 2007) $
046 * @since Validator 1.3.0
047 */
048 public class PercentValidator extends BigDecimalValidator {
049
050 private static final PercentValidator VALIDATOR = new PercentValidator();
051
052 /** DecimalFormat's percent (thousand multiplier) symbol */
053 private static final char PERCENT_SYMBOL = '%';
054
055 private static final BigDecimal POINT_ZERO_ONE = new BigDecimal("0.01");
056
057 /**
058 * Return a singleton instance of this validator.
059 * @return A singleton instance of the PercentValidator.
060 */
061 public static BigDecimalValidator getInstance() {
062 return VALIDATOR;
063 }
064
065 /**
066 * Construct a <i>strict</i> instance.
067 */
068 public PercentValidator() {
069 this(true);
070 }
071
072 /**
073 * Construct an instance with the specified strict setting.
074 *
075 * @param strict <code>true</code> if strict
076 * <code>Format</code> parsing should be used.
077 */
078 public PercentValidator(boolean strict) {
079 super(strict, PERCENT_FORMAT, true);
080 }
081
082 /**
083 * <p>Parse the value with the specified <code>Format</code>.</p>
084 *
085 * <p>This implementation is lenient whether the currency symbol
086 * is present or not. The default <code>NumberFormat</code>
087 * behaviour is for the parsing to "fail" if the currency
088 * symbol is missing. This method re-parses with a format
089 * without the currency symbol if it fails initially.</p>
090 *
091 * @param value The value to be parsed.
092 * @param formatter The Format to parse the value with.
093 * @return The parsed value if valid or <code>null</code> if invalid.
094 */
095 protected Object parse(String value, Format formatter) {
096
097 // Initial parse of the value
098 BigDecimal parsedValue = (BigDecimal)super.parse(value, formatter);
099 if (parsedValue != null || !(formatter instanceof DecimalFormat)) {
100 return parsedValue;
101 }
102
103 // Re-parse using a pattern without the percent symbol
104 DecimalFormat decimalFormat = (DecimalFormat)formatter;
105 String pattern = decimalFormat.toPattern();
106 if (pattern.indexOf(PERCENT_SYMBOL) >= 0) {
107 StringBuffer buffer = new StringBuffer(pattern.length());
108 for (int i = 0; i < pattern.length(); i++) {
109 if (pattern.charAt(i) != PERCENT_SYMBOL) {
110 buffer.append(pattern.charAt(i));
111 }
112 }
113 decimalFormat.applyPattern(buffer.toString());
114 parsedValue = (BigDecimal)super.parse(value, decimalFormat);
115
116 // If parsed OK, divide by 100 to get percent
117 if (parsedValue != null) {
118 parsedValue = parsedValue.multiply(POINT_ZERO_ONE);
119 }
120
121 }
122 return parsedValue;
123 }
124 }