Java Reflection Method Invoke invokeMethod(Object obj, String method)

Description

Invoke the method without parameters over the target object

License

Apache License

Parameter

Parameter	Description
obj	target object
method	method name

Exception

Parameter	Description
IllegalArgumentException	an exception
IllegalAccessException	an exception
InvocationTargetException	an exception
NoSuchMethodException	an exception

Return

value returned by the method invocation

Declaration

public static Object invokeMethod(Object obj, String method) throws IllegalArgumentException,
        IllegalAccessException, InvocationTargetException, NoSuchMethodException 

Method Source Code

//package com.java2s;
/**/*  w w  w. j  a  v a  2  s. c o m*/
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you 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.InvocationTargetException;
import java.lang.reflect.Method;

public class Main {
    /**
     * Invoke the method without parameters over the target object
     * 
     * @param obj target object
     * @param method method name
     * @return value returned by the method invocation
     * @throws IllegalArgumentException
     * @throws IllegalAccessException
     * @throws InvocationTargetException
     * @throws NoSuchMethodException
     */
    public static Object invokeMethod(Object obj, String method) throws IllegalArgumentException,
            IllegalAccessException, InvocationTargetException, NoSuchMethodException {
        return invokeMethod(obj, method, new Object[0]);
    }

    /**
     * Invoke the method over the target object
     * 
     * @param obj target object
     * @param method method name
     * @param params parameters
     * @return value returned by the method invocation
     * @throws IllegalArgumentException
     * @throws IllegalAccessException
     * @throws InvocationTargetException
     * @throws NoSuchMethodException
     */
    public static Object invokeMethod(Object obj, String method, Object[] params) throws IllegalArgumentException,
            IllegalAccessException, InvocationTargetException, NoSuchMethodException {
        return invokeMethod(obj, getMethod(getClass(obj), method, params), params);
    }

    /**
     * Invoke the method without parameters over the target object
     * 
     * @param obj target object
     * @param method method
     * @return value returned by the method invocation
     * @throws IllegalArgumentException
     * @throws IllegalAccessException
     * @throws InvocationTargetException
     */
    public static Object invokeMethod(Object obj, Method method)
            throws IllegalArgumentException, IllegalAccessException, InvocationTargetException {
        return invokeMethod(obj, method, new Object[0]);
    }

    /**
     * Invoke the method over the target object
     * 
     * @param obj target object
     * @param method method
     * @param params parameters
     * @return value returned by the method invocation
     * @throws IllegalArgumentException
     * @throws IllegalAccessException
     * @throws InvocationTargetException
     */
    public static Object invokeMethod(Object obj, Method method, Object[] params)
            throws IllegalArgumentException, IllegalAccessException, InvocationTargetException {
        return method.invoke(obj, params);
    }

    /**
     * Get the method based on its name
     * 
     * @param cls target class
     * @param method method name
     * @param params parameters
     * @return method
     * @throws NoSuchMethodException
     */
    public static Method getMethod(Class<?> cls, String method, Object[] params) throws NoSuchMethodException {
        Class<?>[] classes = new Class[params.length];
        for (int i = 0; i < params.length; i++) {
            classes[i] = params[i].getClass();
        }
        return cls.getMethod(method, classes);
    }

    /**
     * Get the actual class
     * 
     * @param obj target object
     * @return actual class
     */
    public static Class<?> getClass(Object obj) {
        Class<?> cls = obj.getClass();
        while (isProxied(cls)) {
            cls = cls.getSuperclass();
        }
        return cls;
    }

    /**
     * Check is the class is proxies
     * 
     * @param cls class
     * @return proxied
     */
    public static boolean isProxied(Class<?> cls) {
        return cls.getName().contains("$$EnhancerByCGLIB$$") || cls.getName().contains("$$FastClassByCGLIB$$")
                || cls.getName().contains("_$$_javassist") || cls.getName().contains("_$$_WeldSubclass")
                || cls.getName().contains("$Proxy$");
    }
}

Related

1. invokeMethod(Object o, String methodName, Object... args)
2. invokeMethod(Object o, String methodName, Object[] params)
3. invokeMethod(Object obj, Class type, String name, Class[] parameterTypes, Object[] parameters)
4. invokeMethod(Object obj, Method method, Object... args)
5. invokeMethod(Object obj, String mehtodName, Object... parameter)
6. invokeMethod(Object obj, String method, Object... args)
7. invokeMethod(Object obj, String methodName, Object... args)
8. invokeMethod(Object obj, String methodName, Object... args)
9. invokeMethod(Object obj, String methodname, Object... args)