/*
* =============================================================================
*
* Copyright (c) 2011-2014, The THYMELEAF team (http://www.thymeleaf.org)
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* =============================================================================
*/
package org.thymeleaf.spring4.expression;
import org.springframework.core.convert.TypeDescriptor;
import org.springframework.expression.EvaluationContext;
import org.springframework.expression.TypeConverter;
import org.thymeleaf.Configuration;
import org.thymeleaf.context.IProcessingContext;
import org.thymeleaf.standard.expression.AbstractStandardConversionService;
/**
* <p>
* Implementation of {@link org.thymeleaf.standard.expression.IStandardConversionService} that delegates
* to Spring's type conversion system.
* </p>
* <p>
* If there is a {@link org.springframework.core.convert.ConversionService} available at the application
* context, it will be used for conversion.
* </p>
*
* @author Daniel Fernández
*
* @since 2.1.0
*
*/
public final class SpringStandardConversionService extends AbstractStandardConversionService {
private static final TypeDescriptor TYPE_STRING = TypeDescriptor.valueOf(String.class);
public SpringStandardConversionService() {
// Should only be instanced from SpringStandardDialect
super();
}
@Override
protected String convertToString(final Configuration configuration, final IProcessingContext processingContext, final Object object) {
if (object == null) {
return null;
}
final TypeDescriptor objectTypeDescriptor = TypeDescriptor.forObject(object);
final TypeConverter typeConverter = getSpringConversionService(processingContext);
if (typeConverter == null || !typeConverter.canConvert(objectTypeDescriptor, TYPE_STRING)) {
return super.convertToString(configuration, processingContext, object);
}
return (String) typeConverter.convertValue(object, objectTypeDescriptor, TYPE_STRING);
}
@Override
protected <T> T convertOther(final Configuration configuration, final IProcessingContext processingContext, final Object object, final Class<T> targetClass) {
if (object == null) {
return null;
}
final TypeDescriptor objectTypeDescriptor = TypeDescriptor.forObject(object);
final TypeDescriptor targetTypeDescriptor = TypeDescriptor.valueOf(targetClass);
final TypeConverter typeConverter = getSpringConversionService(processingContext);
if (typeConverter == null || !typeConverter.canConvert(objectTypeDescriptor, targetTypeDescriptor)) {
return super.convertOther(configuration, processingContext, object, targetClass);
}
return (T) typeConverter.convertValue(object, objectTypeDescriptor, targetTypeDescriptor);
}
private static TypeConverter getSpringConversionService(final IProcessingContext processingContext) {
final EvaluationContext evaluationContext =
(EvaluationContext) processingContext.getContext().getVariables().
get(ThymeleafEvaluationContext.THYMELEAF_EVALUATION_CONTEXT_CONTEXT_VARIABLE_NAME);
if (evaluationContext != null) {
return evaluationContext.getTypeConverter();
}
return null;
}
}