I have the ability to run code that lets me make calculations and/or get variable information from a program. However I do not have access to the base code, and wondering if there is a way to print out all the methods an Object has available (public)?

Example the Class Shape, with sub classes of Circle and Square. If I was able to print out methods to Circle I would possibly see:

.getRadius()
.setRadius(newValue)

but Square would have

 .getSide()
 .setSide(newValue)

I have a myObject, where I know I can get

myObject[1].GetLength()
myObject[1].getDimUom()
myObject[1].getQuantity().getValue()

However I am unaware of what I can set only certain things like (by trial and error)

myObject[1].setClass(newValue)

So I would like to be able to find a way to print out the method names from an Object; again without any ability to see or modify base code (like adding reflection)

CodePudding user response：

What you basically want is to brake the information hiding principle which is the most fundamental principle in OOP.

What You (most likely) really want is to define a common behavior that could be implemented by the subclasses in their specific way. Regarding your example this could be a method changeSizeTo(int newValue) defined in an interface that would be implemented by your classes and each class would do something specific.

[update]

I mean anything available to public is it really hiding? – Edward

The point is not about the actual access modifiers but the question: "Does this force the caller to know what subclass this object actually is?"

CodePudding user response：

Solution

You can use reflection.

Class clazz = circle.getRadius().getClass();

Method[] methods = clazz.getMethods();

for ( Method method : methods ) {
     System.out.println( method.getName() );
}

With that said, you should listen to the advice given by @Timothy Truckle. You most likely have a design problem if you need to use this, assuming you aren't writing a framework or a library