Java: Delegation Pattern and Protected Methods

Question

I have been using delegation pattern to wrap an object created by a factory in a 3rd party library. Recently, the library added a protected method in the base class and my wrapper class doesn't work any longer. Does anyone have a good solution without resorting to reflection?

This is in 3rd party library and in their package,

public class Base {
    public void foo();

    protected void bar(); // Newly added
}

This is in my own package,

public class MyWrapper extends Base {
    private Base delegate;

    public MyWrapper(Base delegate) {
        this.delegate = delegate;
    }

    public void foo() {
        delegate.foo()
    }

    protected void bar() {
        // Don't know what to do
    }
}

EDIT: My original post wasn't clear. These 2 classes are in different packages.

To answer the question why I need delegation. This is a typical use-case of Delegation/Wrapper pattern and I can't show it here in a few lines of code. The library exposes Base class but the actual object from their factory is a derived class of Base. The actual class changes depending on configuration. So I don't know what delegate is. Therefore straight inheritance pattern doesn't work here.

Answer 1

Access Levels
Modifier    Class   Package Subclass    World
public      Y          Y        Y         Y
protected   Y          Y        Y         N
no modifier Y          Y        N         N
private     Y          N        N         N

protected has package access too, do you see any specific issue with this:

class Base {
        public void foo(){};

        protected void bar(){}; // Newly added
    }

    class MyWrapper  {
        private Base delegate;

        public MyWrapper(Base delegate) {
            this.delegate = delegate;
        }

        public void foo() {
            delegate.foo();
        }

        protected void bar() {
            // Don't know what to do
            delegate.bar(); //since its in same package, it can be referenced, do you expect compile time error?
        }
    }

Further while using delegator pattern why wrapper class extends Base class, I don't see specific need since you already have an instance of Base. To me it seems more of an decorator.