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.text.Format;
020import java.text.ParsePosition;
021import java.util.Locale;
022
023import org.apache.wicket.util.convert.ConversionException;
024import org.apache.wicket.util.convert.IConverter;
025
026
027/**
028 * Base class for locale aware type converters.
029 * 
030 * @author Eelco Hillenius
031 * @param <C>
032 */
033public abstract class AbstractConverter<C> implements IConverter<C>
034{
035        private static final long serialVersionUID = 1L;
036
037        /**
038         * Parses a value using one of the java.util.text format classes.
039         * 
040         * @param format
041         *            The format to use
042         * @param value
043         *            The object to parse
044         * @param locale
045         *            The locale to use to parse.
046         * @return The object
047         * @throws ConversionException
048         *             Thrown if parsing fails
049         */
050        @SuppressWarnings("unchecked")
051        protected C parse(final Format format, final Object value, final Locale locale)
052        {
053                final ParsePosition position = new ParsePosition(0);
054                final String stringValue = value.toString();
055                final C result = (C)format.parseObject(stringValue, position);
056
057                if (position.getIndex() != stringValue.length())
058                {
059                        throw newConversionException("Cannot parse '" + value + "' using format " + format,
060                                value, locale).setFormat(format);
061                }
062                return result;
063        }
064
065        /**
066         * Creates a conversion exception for throwing
067         * 
068         * @param message
069         *            The message
070         * @param value
071         *            The value that didn't convert
072         * @param locale
073         *            The locale
074         * @return The ConversionException
075         */
076        protected ConversionException newConversionException(final String message, final Object value,
077                final Locale locale)
078        {
079                return new ConversionException(message).setSourceValue(value)
080                        .setTargetType(getTargetType())
081                        .setConverter(this)
082                        .setLocale(locale);
083        }
084
085        /**
086         * @return The target type of this type converter
087         */
088        protected abstract Class<C> getTargetType();
089
090        /**
091         * @see org.apache.wicket.util.convert.IConverter#convertToString(java.lang.Object, Locale)
092         */
093        @Override
094        public String convertToString(final C value, final Locale locale)
095        {
096                if (value == null)
097                {
098                        return null;
099                }
100                return value.toString();
101        }
102}