001/*
002 * Copyright 2002-2017 the original author or authors.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *      https://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package org.springframework.expression.spel.support;
018
019import org.springframework.core.convert.ConversionException;
020import org.springframework.core.convert.ConversionService;
021import org.springframework.core.convert.TypeDescriptor;
022import org.springframework.core.convert.support.DefaultConversionService;
023import org.springframework.expression.TypeConverter;
024import org.springframework.expression.spel.SpelEvaluationException;
025import org.springframework.expression.spel.SpelMessage;
026import org.springframework.util.Assert;
027
028/**
029 * Default implementation of the {@link TypeConverter} interface,
030 * delegating to a core Spring {@link ConversionService}.
031 *
032 * @author Juergen Hoeller
033 * @author Andy Clement
034 * @since 3.0
035 * @see org.springframework.core.convert.ConversionService
036 */
037public class StandardTypeConverter implements TypeConverter {
038
039        private final ConversionService conversionService;
040
041
042        /**
043         * Create a StandardTypeConverter for the default ConversionService.
044         */
045        public StandardTypeConverter() {
046                this.conversionService = DefaultConversionService.getSharedInstance();
047        }
048
049        /**
050         * Create a StandardTypeConverter for the given ConversionService.
051         * @param conversionService the ConversionService to delegate to
052         */
053        public StandardTypeConverter(ConversionService conversionService) {
054                Assert.notNull(conversionService, "ConversionService must not be null");
055                this.conversionService = conversionService;
056        }
057
058
059        @Override
060        public boolean canConvert(TypeDescriptor sourceType, TypeDescriptor targetType) {
061                return this.conversionService.canConvert(sourceType, targetType);
062        }
063
064        @Override
065        public Object convertValue(Object value, TypeDescriptor sourceType, TypeDescriptor targetType) {
066                try {
067                        return this.conversionService.convert(value, sourceType, targetType);
068                }
069                catch (ConversionException ex) {
070                        throw new SpelEvaluationException(ex, SpelMessage.TYPE_CONVERSION_ERROR,
071                                        (sourceType != null ? sourceType.toString() : (value != null ? value.getClass().getName() : "null")),
072                                        targetType.toString());
073                }
074        }
075
076}