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/*
* Copyright 2004-2012 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
*
* https://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.binding.method;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.binding.collection.AbstractCachingMapDecorator;
import org.springframework.binding.convert.ConversionService;
import org.springframework.binding.convert.service.DefaultConversionService;
import org.springframework.core.style.StylerUtils;
/**
* A helper for invoking typed methods on arbitrary objects, with support for argument value type conversion from values
* retrieved from an argument attribute source, and conversion of the result to a desired type.
*
* @author Keith Donald
* @author Jeremy Grelle
*/
public class MethodInvoker {
private static final Log logger = LogFactory.getLog(MethodInvoker.class);
/**
* Conversion service for converting arguments to the necessary type if required.
*/
private ConversionService conversionService = new DefaultConversionService();
/**
* A cache of invoked bean methods, keyed weakly.
*/
@SuppressWarnings("serial")
private AbstractCachingMapDecorator methodCache = new AbstractCachingMapDecorator(true) {
public Method create(MethodKey key) {
return key.getMethod();
}
};
/**
* Sets the conversion service to convert argument values as needed.
*/
public void setConversionService(ConversionService conversionService) {
this.conversionService = conversionService;
}
/**
* Invoke the method on the bean provided. Argument values are pulled from the provided argument source.
* @param signature the definition of the method to invoke, including the method name and the method argument types
* @param bean the bean to invoke
* @param argumentSource the source for method arguments
* @return the invoked method's return value
* @throws MethodInvocationException the method could not be invoked
*/
public Object invoke(MethodSignature signature, Object bean, Object argumentSource)
throws MethodInvocationException {
Parameters parameters = signature.getParameters();
Object[] arguments = new Object[parameters.size()];
for (int i = 0; i < parameters.size(); i++) {
Parameter parameter = parameters.getParameter(i);
Object argument = parameter.evaluateArgument(argumentSource);
arguments[i] = applyTypeConversion(argument, parameter.getType());
}
Class[] parameterTypes = parameters.getTypesArray();
for (int i = 0; i < parameterTypes.length; i++) {
if (parameterTypes[i] == null) {
Object argument = arguments[i];
if (argument != null) {
parameterTypes[i] = argument.getClass();
}
}
}
MethodKey key = new MethodKey(bean.getClass(), signature.getMethodName(), parameterTypes);
try {
Method method = methodCache.get(key);
if (logger.isDebugEnabled()) {
logger.debug("Invoking method with signature [" + key + "] with arguments "
+ StylerUtils.style(arguments) + " on bean [" + bean + "]");
}
Object returnValue = method.invoke(bean, arguments);
if (logger.isDebugEnabled()) {
logger.debug("Invoked method with signature [" + key + "] returned value [" + returnValue + "]");
}
return returnValue;
} catch (InvocationTargetException e) {
throw new MethodInvocationException(signature, arguments, e.getTargetException());
} catch (Exception e) {
throw new MethodInvocationException(signature, arguments, e);
}
}
/**
* Apply type conversion on the supplied value
*
* @param value the raw value to be converted
* @param targetType the target type for the conversion
* @return the converted result
*/
protected Object applyTypeConversion(Object value, Class targetType) {
if (value == null || targetType == null) {
return value;
}
return conversionService.getConversionExecutor(value.getClass(), targetType).execute(value);
}
}