Accessing methods of Observable class in Observer class

How do you access a method/instance from an Observable class in an Observer class where the method/instance is not the object being observed.

For example, if these getter methods were in my Observable class but only book was being observed, how would I access name and store in my Observer class (namely in the update() method)?

public class MethodEx extends Observable {
        ...
    public String getName(){
        return this.name;
    }

    public String getBook(){
        return this.book;
    }

    public String getStore(){
        return this.store;
    }
}