/*
* Copyright 2002-2014 the original author or authors.
*
* 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.springframework.messaging.converter;
import org.springframework.core.convert.ConversionException;
import org.springframework.core.convert.ConversionService;
import org.springframework.core.convert.support.DefaultConversionService;
import org.springframework.messaging.Message;
import org.springframework.util.Assert;
import org.springframework.util.ClassUtils;
/**
* An extension of the {@link SimpleMessageConverter} that uses a
* {@link ConversionService} to convert the payload of the message
* to the requested type.
*
* <p>Return {@code null} if the conversion service cannot convert
* from the payload type to the requested type.
*
* @author Stephane Nicoll
* @since 4.1
* @see ConversionService
*/
public class GenericMessageConverter extends SimpleMessageConverter {
private final ConversionService conversionService;
/**
* Create a new instance with a default {@link ConversionService}.
*/
public GenericMessageConverter() {
this.conversionService = new DefaultConversionService();
}
/**
* Create a new instance with the given {@link ConversionService}.
*/
public GenericMessageConverter(ConversionService conversionService) {
Assert.notNull(conversionService, "ConversionService must not be null");
this.conversionService = conversionService;
}
@Override
public Object fromMessage(Message<?> message, Class<?> targetClass) {
Object payload = message.getPayload();
if (targetClass == null) {
return payload;
}
if (payload != null && this.conversionService.canConvert(payload.getClass(), targetClass)) {
try {
return this.conversionService.convert(payload, targetClass);
}
catch (ConversionException ex) {
throw new MessageConversionException(message, "Failed to convert message payload '" +
payload + "' to '" + targetClass.getName() + "'", ex);
}
}
return (ClassUtils.isAssignableValue(targetClass, payload) ? payload : null);
}
}