CS311 Handouts Updated

Contents

Booklet of Introduction to Web Services Development ..................................................................... 1 Contents ................................................................................................................................................ 2

Module 2: Basics of Java Programming ............................................................................................. 38 Module 3: (Program Control Flow) .................................................................................................... 46 Module 4: (Using Objects) .................................................................................................................. 56 Module 5: (Primitive values as objects) ............................................................................................. 71 Module 6: (Arrays) .............................................................................................................................. 76 Module 7: (Classes) ............................................................................................................................. 82 Module 8 (Object Communication) .................................................................................................118 Module 9: (Modifiers) .......................................................................................................................129 Module 10: (Exception Handling) .....................................................................................................143 Module 11: (XML) .............................................................................................................................153 Module 12: (XML) .............................................................................................................................175 Module 13 :( XML DOM) ...................................................................................................................197 Modue 14: Introduction to JAXP ......................................................................................................246 Module 15: (Servlets) ........................................................................................................................263 Module-16: Java Database Connectivity (JDBC) ..............................................................................327 Module 17 Introduction WebServices .............................................................................................338 Module 18 Web Services Architecture ............................................................................................345 Module 19 Web Services with JAX-WS ............................................................................................353

Objective:

In this lecture we will discuss Object Orientation in detail. It will be followed by discussion on Data Modeling with reference to Abstraction, Inheritance, Encapsulation and Information Hiding, what are the advantages and they are used in classes and their examples.

What is an Object Orientation?

In real world, object oriented approach focuses on objects that represents abstract or concrete things.

What is a Model?

Modeling is an approach that is used at the beginning of software. The reasons to model a system are: Communication: Model diagrams before implementation can be more understandable and can allow users to give developers feedback on the appropriate structure of the system. Abstraction: The goal of the software methodology is to first what functionality is used and then how to take this abstract description and refine it into an implementable design.

What is an Object?

For understanding an object orientation, you need to understand object first. Objects are key to understand object-oriented. Look around yourself and you'll find many examples of real-world objects: your dog, your desk, your television set, your bicycle. Object is something tangible. Object has two characteristics; state and behavior. State is a noun, attribute, a well-defined behavior and behavior is a certain operation. For example dog which is a tangible object, an object which can be touched has a state of colour, name, and breed and has behavior of barking, fetching.

Object

" Object" can be a combination of variables and functions. You may also notice that some objects, in turn, will also contain other objects. Relationships of identified objects are constructed (such as relating a person's age to a specific person). For example there are several objects like Ali, House, Car, and Tree. Relationships are built between these objects like; Ali lives in the house and Ali drives a car. In these two sentences, Ali, house and car are objects which interact with each other and form a certain relation. Time is another example in which Hours, minutes and seconds are the objects and the operations performed on time like set Hours, set minutes and set seconds are the behavior and operations performed on the object.

Advantages:

In real world, we are surrounded by objects. Modeling picks up each thing/object in the real world which is involved in the requirement. It makes the requirement simple and easily understandable by representing simple diagrams.

What is Abstraction?

Abstraction is the process of taking out characteristics from something in order to reduce it into a set of essential characteristics. Through the process of abstraction, a programmer hides all the irrelevant data about an object in order to reduce complexity and increase efficiency.