/*
* Copyright 2002-2015 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.Method;
import java.lang.reflect.Modifier;
import org.springframework.core.MethodParameter;
import org.springframework.core.convert.TypeDescriptor;
import org.springframework.expression.AccessException;
import org.springframework.expression.EvaluationContext;
import org.springframework.expression.MethodExecutor;
import org.springframework.expression.TypedValue;
import org.springframework.util.ReflectionUtils;
/**
* @author Andy Clement
* @author Juergen Hoeller
* @since 3.0
*/
public class ReflectiveMethodExecutor implements MethodExecutor {
private final Method method;
private final Integer varargsPosition;
private boolean computedPublicDeclaringClass = false;
private Class<?> publicDeclaringClass;
private boolean argumentConversionOccurred = false;
public ReflectiveMethodExecutor(Method method) {
this.method = method;
if (method.isVarArgs()) {
Class<?>[] paramTypes = method.getParameterTypes();
this.varargsPosition = paramTypes.length - 1;
}
else {
this.varargsPosition = null;
}
}
public Method getMethod() {
return this.method;
}
/**
* Find the first public class in the methods declaring class hierarchy that declares this method.
* Sometimes the reflective method discovery logic finds a suitable method that can easily be
* called via reflection but cannot be called from generated code when compiling the expression
* because of visibility restrictions. For example if a non public class overrides toString(), this
* helper method will walk up the type hierarchy to find the first public type that declares the
* method (if there is one!). For toString() it may walk as far as Object.
*/
public Class<?> getPublicDeclaringClass() {
if (!computedPublicDeclaringClass) {
this.publicDeclaringClass = discoverPublicClass(method, method.getDeclaringClass());
this.computedPublicDeclaringClass = true;
}
return this.publicDeclaringClass;
}
private Class<?> discoverPublicClass(Method method, Class<?> clazz) {
if (Modifier.isPublic(clazz.getModifiers())) {
try {
clazz.getDeclaredMethod(method.getName(), method.getParameterTypes());
return clazz;
}
catch (NoSuchMethodException ex) {
// Continue below...
}
}
Class<?>[] ifcs = clazz.getInterfaces();
for (Class<?> ifc: ifcs) {
discoverPublicClass(method, ifc);
}
if (clazz.getSuperclass() != null) {
return discoverPublicClass(method, clazz.getSuperclass());
}
return null;
}
public boolean didArgumentConversionOccur() {
return this.argumentConversionOccurred;
}
@Override
public TypedValue execute(EvaluationContext context, Object target, Object... arguments) throws AccessException {
try {
if (arguments != null) {
this.argumentConversionOccurred = ReflectionHelper.convertArguments(context.getTypeConverter(), arguments, this.method, this.varargsPosition);
}
if (this.method.isVarArgs()) {
arguments = ReflectionHelper.setupArgumentsForVarargsInvocation(this.method.getParameterTypes(), arguments);
}
ReflectionUtils.makeAccessible(this.method);
Object value = this.method.invoke(target, arguments);
return new TypedValue(value, new TypeDescriptor(new MethodParameter(this.method, -1)).narrow(value));
}
catch (Exception ex) {
throw new AccessException("Problem invoking method: " + this.method, ex);
}
}
}