The MVC design pattern is very simple to understand but much more difficult to live with. You just need this little bit of Business Logic in the View logic or you need just that little bit of View logic in the Business tier and pretty soon you have a real mess. Making ActionForm a class takes advantage of the single inheritance restriction of Java to it makes it more difficult for people to do things that they should not do.

No, not quite. An abstract class in C++ cannot be instantiated, but it can (and often does) contain implementation code and/or data members. A C# interface cannot contain any implementation code or data members - it is simply a group of method names & signatures. A C# interface is more like a COM interface than a C++ abstract class.

Latest Answer: hi, Diff b/w abstract class and interface are.. Abstract class can have concrete me... Latest Answer: See the base class(super class) of all classes is Object class.Other wise when u creat a class ,and ...

It must provide all of the methods in the interface and identify the interface in its implements clause.

Set the Browsable attribute on the new property that hides the existing one. Here is a code snippet that hides the WordWrap property in the derived TextBox. [C#] public class CustomTextBox : TextBox { [ Browsable( false ) ] public new bool WordWrap {...

Form_Initialize, Form_Load, Form_QueryUnload, Form_UnloadB) Form_Load, Form_Initialize, Form_QueryUnload, Form_UnloadC) Form_Initialize, Form_Load, Form_Unload, Form_QueryUnloadD) Form_Load, Form_

The principal difference is that an abstract class is used when you have a type/subtype relationship. An interface does not imply a type/subtype hierarchy; it merely forces a class to have some methods with a given signature. That allows some other code to rely on being able to call those methods. You want to subclass abstract classes when you are making subtypes that define the abstract behavior. The subclass should have a "kind of" relationship to the superclass.

There is no method in interface can be called. Only the actual implementation of that method in class, which implements the interface mentioned, can be called.

Yes and no. All types can be treated as if they derive from object (System.Object), but in order to treat an instance of a value type (e.g. int, float) as object-derived, the instance must be converted to a reference type using a process called 'boxing'. In theory a developer can forget about this and let the run-time worry about when the conversion is necessary, but in reality this implicit conversion can have side-effects that may trip up the unwary.

I inherit the class Car of the class Vehicle, for example. Can I call the constructor of Vehicle, from the constructor of Car? I do that in Java. Java has the "super" keyword to call the constructor of a class from the constructor of an inherited class. There is no equivalent in Scriptol. If you call the constructor of the base class, this create a new instance of the base class. But you can assign the attributes of the base class from the constructor of the inherited class.

Every class that is not extending another class is implicitly extending Object class in Java. So java.lang.Object class is the super most class of all classes in Java. Whereas an abstract class can contains abstract methods without any body but it can also have non-abstract methods with body (which is not possible with interfaces). However, interface and abstract classes can not have objects. They can only have object references which point to object of implementing class or sub class.

Ans: 124. class a125. {126. public virtual int m()127. {128. return 1;129. }130. }131. class b:a132. {133. public int j()134. {135. return m();136. } }

I have a heterogeneous list of objects, and my code needs to do class-specific things to the objects. Seems like this ought to use dynamic binding but can't figure it out. What should I do? Updated!

object of a derived class is a kind of the base class. Therefore the conversion from a derived class pointer to a base class pointer is perfectly safe, and happens all the time. For example, if I am pointing at a car, I am in fact pointing at a vehicle, so converting a Car* to a Vehicle* is perfectly safe and normal:

Derived classes do not get access to private members of a base class. This effectively "seals off" the derived class from any changes made to the private members of the base class.

This is an interesting question. As a newbie, it is a good practice to create a new ActionForm for each action sequence. You can use DynaActionForms to help reduce the effort required, or use the code generation facilities of your IDE. Validation - You might need to use different validation rules depending upon the action that is currently being executed. Persistence - Be careful that a form populated in one action is not unexpectedly reused in a different action.

The Integrated Student Information System (ISIS) will not be replaced until Phase 3 of the project. There will be several interfaces between ISIS and the Integrated System to transact business in the areas of financial aid and collection and recording of tuition and fees. Other systems (e.g., Maximo) may never be replaced by the Integrated System if they offer unique features required by the specific business operation.