/*
* Copyright 2002-2010 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.expression.spel.support;
import java.lang.reflect.Constructor;
import org.springframework.core.convert.TypeDescriptor;
import org.springframework.expression.AccessException;
import org.springframework.expression.ConstructorExecutor;
import org.springframework.expression.EvaluationContext;
import org.springframework.expression.TypedValue;
import org.springframework.util.ReflectionUtils;
/**
* A simple ConstructorExecutor implementation that runs a constructor using reflective invocation.
*
* @author Andy Clement
* @author Juergen Hoeller
* @since 3.0
*/
class ReflectiveConstructorExecutor implements ConstructorExecutor {
private final Constructor<?> ctor;
private final Integer varargsPosition;
// When the constructor was found, we will have determined if arguments need to be converted for it
// to be invoked. Conversion won't be cheap so let's only do it if necessary.
private final int[] argsRequiringConversion;
public ReflectiveConstructorExecutor(Constructor<?> ctor, int[] argsRequiringConversion) {
this.ctor = ctor;
if (ctor.isVarArgs()) {
Class[] paramTypes = ctor.getParameterTypes();
this.varargsPosition = paramTypes.length - 1;
}
else {
this.varargsPosition = null;
}
this.argsRequiringConversion = argsRequiringConversion;
}
public TypedValue execute(EvaluationContext context, Object... arguments) throws AccessException {
try {
if (this.argsRequiringConversion != null && arguments != null) {
ReflectionHelper.convertArguments(context.getTypeConverter(), arguments,
this.ctor, this.argsRequiringConversion, this.varargsPosition);
}
if (this.ctor.isVarArgs()) {
arguments = ReflectionHelper.setupArgumentsForVarargsInvocation(this.ctor.getParameterTypes(), arguments);
}
ReflectionUtils.makeAccessible(this.ctor);
return new TypedValue(this.ctor.newInstance(arguments), TypeDescriptor.valueOf(this.ctor.getDeclaringClass()));
}
catch (Exception ex) {
throw new AccessException("Problem invoking constructor: " + this.ctor, ex);
}
}
}
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