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.wicket.util.convert.converter;
018
019import java.math.BigDecimal;
020import java.text.DecimalFormat;
021import java.text.DecimalFormatSymbols;
022import java.text.NumberFormat;
023import java.util.Locale;
024import java.util.concurrent.ConcurrentHashMap;
025
026import org.apache.wicket.util.convert.ConversionException;
027
028
029/**
030 * Base class for all number converters.
031 * 
032 * @author Jonathan Locke
033 * @param <N>
034 */
035public abstract class AbstractNumberConverter<N extends Number> extends AbstractConverter<N>
036{
037        private static final long serialVersionUID = 1L;
038
039        /** The date format to use */
040        private final ConcurrentHashMap<Locale, NumberFormat> numberFormats = new ConcurrentHashMap<>();
041
042        /**
043         * @param locale
044         *            The locale
045         * @return Returns the numberFormat.
046         */
047        public NumberFormat getNumberFormat(final Locale locale)
048        {
049                NumberFormat numberFormat = numberFormats.get(locale);
050                if (numberFormat == null)
051                {
052                        numberFormat = newNumberFormat(locale);
053
054                        if (numberFormat instanceof DecimalFormat)
055                        {
056                                // always try to parse BigDecimals
057                                ((DecimalFormat)numberFormat).setParseBigDecimal(true);
058                        }
059
060                        NumberFormat tmpNumberFormat = numberFormats.putIfAbsent(locale, numberFormat);
061                        if (tmpNumberFormat != null)
062                        {
063                                numberFormat = tmpNumberFormat;
064                        }
065                }
066                // return a clone because NumberFormat.get..Instance use a pool
067                return (NumberFormat)numberFormat.clone();
068        }
069
070        /**
071         * Creates a new {@link NumberFormat} for the given locale. The instance is later cached and is
072         * accessible through {@link #getNumberFormat(Locale)}
073         *
074         * @param locale
075         * @return number format
076         */
077        protected abstract NumberFormat newNumberFormat(final Locale locale);
078
079        /**
080         * Parses a value as a String and returns a Number.
081         * 
082         * @param value
083         *            The object to parse (after converting with toString())
084         * @param min
085         *            The minimum allowed value or {@code null} if none
086         * @param max
087         *            The maximum allowed value or {@code null} if none
088         * @param locale
089         * @return The number
090         * @throws ConversionException
091         *             if value is unparsable or out of range
092         */
093        protected BigDecimal parse(Object value, final BigDecimal min, final BigDecimal max, Locale locale)
094        {
095                if (locale == null)
096                {
097                        locale = Locale.getDefault(Locale.Category.FORMAT);
098                }
099
100                if (value == null)
101                {
102                        return null;
103                }
104                else if (value instanceof String)
105                {
106                        char groupingSeparator = DecimalFormatSymbols.getInstance(locale).getGroupingSeparator();
107                        // Convert spaces to no-break space (groupingSeparator) as required by Java formats:
108                        // http://bugs.sun.com/view_bug.do?bug_id=4510618
109                        value = ((String)value).replaceAll("(\\d+)\\s(?=\\d)", "$1" + groupingSeparator);
110                }
111
112                final NumberFormat numberFormat = getNumberFormat(locale);
113                final N number = parse(numberFormat, value, locale);
114
115                if (number == null)
116                {
117                        return null;
118                }
119
120                BigDecimal bigDecimal;
121                if (number instanceof BigDecimal)
122                {
123                        bigDecimal = (BigDecimal)number;
124                }
125                else
126                {
127                        // should occur rarely, see #getNumberFormat(Locale)
128                        bigDecimal = new BigDecimal(number.toString());
129                }
130
131                if (min != null && bigDecimal.compareTo(min) < 0)
132                {
133                        throw newConversionException("Value cannot be less than " + min, value, locale)
134                                        .setFormat(numberFormat);
135                }
136
137                if (max != null && bigDecimal.compareTo(max) > 0)
138                {
139                        throw newConversionException("Value cannot be greater than " + max, value, locale)
140                                        .setFormat(numberFormat);
141                }
142
143                return bigDecimal;
144        }
145
146        @Override
147        public String convertToString(final N value, final Locale locale)
148        {
149                NumberFormat fmt = getNumberFormat(locale);
150                if (fmt != null)
151                {
152                        return fmt.format(value);
153                }
154                return value.toString();
155        }
156}