com.hpe.caf.autoscale.reflection.ReflectionAssistance Maven / Gradle / Ivy
/*
* Copyright 2015-2020 Micro Focus or one of its affiliates.
*
* 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 com.hpe.caf.autoscale.reflection;
import java.lang.reflect.Method;
import java.util.ArrayList;
/**
*
* A utility class to provide reflection assistance
*/
public class ReflectionAssistance
{
/**
* Assists in finding out the method information of the calling object for use with reflection.
* This works out the calling method information, equivilent to object.getClass, but there is no object.getMethod.
*
* @param classToSearch
* @param parameterTypes
* @return
*/
public static Method getCallingMethod(final Class classToSearch, Class... parameterTypes)
{
// we want the method name of the caller of this method
final String methodName = Thread.currentThread().getStackTrace()[2].getMethodName();
Method methodToSearch = null;
try {
methodToSearch = classToSearch.getMethod(methodName, parameterTypes);
} catch (NoSuchMethodException ex) {
// just before we give up, I would love for this to be easier to code up, i.e. without have
// to define the params in the method signature and again in the getcallingmethod call, so fallback
// to a unique method name search, of course if there are 2 methods with same name, but with different signatures then
// they should have passed the correct param types!
Method[] methods = classToSearch.getMethods();
ArrayList listOfFoundsMethods = new ArrayList<>();
for (Method method : methods) {
if (method.getName().equals(methodName)) {
// found a match, add and continue on.
listOfFoundsMethods.add(method);
}
}
if (listOfFoundsMethods.size() == 1) {
// found a single match, so great use this.
return listOfFoundsMethods.get(0);
}
if (listOfFoundsMethods.size() > 1) {
throw new RuntimeException(
"Found more than one method that matches the specified name: " + methodName + ", \r\n"
+ "ensure you have supplied the correct parameter types for your method signature to keep it unique.",
ex);
}
throw new RuntimeException(
"No such method found with name: " + methodName + ", \r\n"
+ "ensure you have supplied the correct parameter types for your method signature.", ex);
} catch (SecurityException ex) {
throw new RuntimeException(ex);
}
return methodToSearch;
}
}