Java Reflection Method Get from Object getMethodInHolder(String methodName, Object holder)

Description

get Method In Holder

License

Apache License

Declaration

public static <T> T getMethodInHolder(String methodName, Object holder) 

Method Source Code

//package com.java2s;
/**//w w w.jav  a 2s.c  o m
 * Copyright (C) 2016 DSpot Sp. z o.o
 * 
 * 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.
 */

import java.lang.reflect.Constructor;
import java.lang.reflect.Method;

public class Main {
    public static <T> T getMethodInHolder(String methodName, Object holder) {
        return getMethodInHolder(methodName, holder, null);
    }

    @SuppressWarnings("unchecked")
    public static <T> T getMethodInHolder(String methodName, Object holder, String subHolder, Object... params) {
        Class<?> clazz = holder.getClass();
        if (subHolder != null) {
            try {
                Method getPluginHolder = getMethod("getPluginHolder", clazz);

                clazz = Class.forName(subHolder);

                //It's assumed only one constructor that takes as parameter the holder
                //TODO ViewsHolder doesn't follow this pattern
                Constructor<?> constructor = clazz.getDeclaredConstructors()[0];
                Object subHolderInstance = constructor.newInstance(holder);

                holder = getPluginHolder.invoke(holder, subHolderInstance);
            } catch (Exception e) {
                e.printStackTrace();
                return null;
            }

        }

        if (clazz == null)
            return null;

        Method method = getMethod(methodName, clazz);
        if (method == null)
            return null;

        try {
            if (params != null && params.length > 0)
                return (T) method.invoke(holder, params);
            else {
                return (T) method.invoke(holder);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }

        return null;
    }

    private static Method getMethod(String methodName, Class<?> clazz) {
        Method method = getDeclaredMethod(methodName, clazz);
        if (method == null) {
            Class<?> parent = clazz.getSuperclass();

            while (parent != null) {
                method = getDeclaredMethod(methodName, parent);
                if (method != null)
                    break;
                parent = parent.getSuperclass();
            }
        }

        return method;
    }

    private static Method getDeclaredMethod(String methodName, Class<?> clazz) {
        Method[] methods = clazz.getDeclaredMethods();
        for (Method method : methods) {
            if (method.getName().equals(methodName)) {
                method.setAccessible(true);
                return method;
            }
        }

        return null;
    }
}

Related

1. getMethodConfigByAnnotaton(Object instance, Class declaringClass, Class annotationType, Class type)
2. getMethodDescriptor(Object instance, String methodName, Class aClass, Class... parameters)
3. getMethodFirstParamType(final String methodName, final Object o)
4. getMethodIfAny(final Object instance, final String name, final Class[] params)
5. getMethodIgnoreCaseWithNoParams(Object o, String p)
6. getMethodInstace(Class c, Object inst, String name, Class[] types, boolean access)
7. getMethodName(AccessibleObject method)
8. getMethodNamed(String methodName, Object holder)
9. getMethodNames(Object obj, boolean hasParent)