Java Reflection Method Static Invoke invokeDefaultStaticMethod(Class expectedClass, String className, String methodName)

Description

invoke Default Static Method

License

Apache License

Declaration

@SuppressWarnings("unchecked")
    public static <T> T invokeDefaultStaticMethod(Class<T> expectedClass, String className, String methodName) 

Method Source Code

//package com.java2s;
// Licensed under the Apache License, Version 2.0 (the "License");

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

public class Main {
    @SuppressWarnings("unchecked")
    public static <T> T invokeDefaultStaticMethod(Class<T> expectedClass, String className, String methodName) {
        Class<?> cls = classForName(className);
        try {/*from   w  w w.java  2 s.c o  m*/
            Method m = cls.getMethod(methodName, new Class[] {});
            T t = (T) m.invoke(null, new Object[] {});
            if (t == null) {
                return t;
            }
            if (expectedClass.isAssignableFrom(t.getClass()) == false) {
                throw new RuntimeException("method: " + methodName + " from class: " + className
                        + " does not return correct class type: " + expectedClass + " but: " + t.getClass());
            }
            return t;
        } catch (NoSuchMethodException ex) {
            throw new RuntimeException("Cannot find method: " + methodName + " in class: " + className);
        } catch (IllegalArgumentException ex) {
            throw new RuntimeException(ex);
        } catch (IllegalAccessException ex) {
            throw new RuntimeException(ex);
        } catch (InvocationTargetException ex) {
            Throwable nex = ex.getCause();
            if (nex instanceof RuntimeException) {
                throw (RuntimeException) nex;
            }
            throw new RuntimeException(ex);
        }
    }

    public static Class<?> classForName(String className) {
        ClassLoader cl = Thread.currentThread().getContextClassLoader();
        try {
            return Class.forName(className, true, cl);
        } catch (Throwable ex) {
            try {
                Class.forName(className, true, cl);
            } catch (Exception ex2) {

            }
            throw new RuntimeException("Failed to load class: " + className + "; " + ex.getMessage(), ex);
        }
    }

    public static <T> Class<T> classForName(String className, Class<T> ifacecls) {
        return (Class<T>) classForName(className);
    }
}

Related

1. invokeReflectStaticMethod(String methodName, Class cl, Object[] parameter, Class[] args)
2. invokeStatic(Class clazz, String methodName, Class returnClass, Object... args)
3. invokeStatic(final Class clazz, final String methodName, final Class[] argTypes, final Object[] args)
4. invokeStatic(final ClassLoader loader, final String className, final String methodName, final Object... parameters)