Java Method Call invoke(Object target, String methodName)

Description

invoke

License

Open Source License

Declaration

private static Object invoke(Object target, String methodName)
            throws Exception 

Method Source Code

//package com.java2s;
// License as published by the Free Software Foundation; either

import java.lang.reflect.Method;

import java.util.Hashtable;

import java.util.Map;

public class Main {
    /** The classloader we should use to load javahelp classes */
    private static ClassLoader classloader = null;
    private static final Object[] NO_ARGS = new Object[0];
    private static Map METHOD_ARGS = new Hashtable();
    private static Map METHODS = new Hashtable();

    private static Object invoke(Object target, String methodName)
            throws Exception {
        return invoke(target, methodName, NO_ARGS);
    }/*from   ww w  .ja  v a2 s  . c o m*/

    private static Object invoke(Object target, String methodName,
            Object arg1) throws Exception {
        return invoke(target, methodName, new Object[] { arg1 });
    }

    private static Object invoke(Object target, String methodName,
            Object arg1, Object arg2) throws Exception {
        return invoke(target, methodName, new Object[] { arg1, arg2 });
    }

    private static Object invoke(Object target, String methodName,
            Object arg1, Object arg2, Object arg3) throws Exception {
        return invoke(target, methodName, new Object[] { arg1, arg2, arg3 });
    }

    private static Object invoke(Object target, String methodName,
            Object[] args) throws Exception {
        try {
            Method m = getMethod(target, methodName);
            if (target instanceof String)
                return m.invoke(null, args);
            else
                return m.invoke(target, args);
        } catch (Exception e) {
            e.printStackTrace();
            throw e;
        }
    }

    private static Method getMethod(Object target, String methodName)
            throws Exception {
        Method result = (Method) METHODS.get(methodName);

        if (result == null) {
            Object[] argTypes = (Object[]) METHOD_ARGS.get(methodName);
            result = getMethod(target, methodName, argTypes);
            METHODS.put(methodName, result);
        }

        return result;
    }

    private static Method getMethod(Object target, String methodName,
            Object[] argTypes) throws Exception {
        Class c = resolveClass(target);

        Class[] paramTypes = new Class[argTypes.length];
        for (int i = 0; i < paramTypes.length; i++)
            paramTypes[i] = resolveClass(argTypes[i]);

        return c.getMethod(methodName, paramTypes);
    }

    private static Class resolveClass(Object obj) throws Exception {
        if (obj instanceof Class)
            return (Class) obj;
        else if (obj instanceof String)
            return classloader.loadClass((String) obj);
        else
            return obj.getClass();
    }
}

Related

1. invoke(Object proxy, java.lang.reflect.Method method, Object[] args)
2. invoke(Object source, String key)
3. invoke(Object target, Class clazz, String methodName, Class[] parameterTypes, Object... args)
4. invoke(Object target, Class clazz, String method)
5. invoke(Object target, Method method)
6. invoke(Object target, String methodName, Object... args)
7. invoke(Object target, String methodName, Object[] args)
8. invoke(Object target, String name, Class[] params, Object[] args)
9. invoke(Object targetObject, String method, Class[] paramTypes, Object[] paramValues)