Unit 23 1

Implementation Phase

• The objective of this section is to introduce how the software design is realized as a set of programs or program units. When you have read this section you will:o understand the importance of the design phase;

o know how the java templates of the design phase are converted into java programs.

Unit 23 2

Now we must focus on implementing the solution as software.

It has two distinct parts:o writing programs that implement the design.o conducting unit tests.

What is Implementation?

Unit 23 3

Here we explain some of the software engineering practices that you should keep in your mind as you write your code.

o Naming Conventions and Coding Standards – Does the organization have its own naming conventions and coding standards? Does the programmer follow these naming conventions and coding standards?

o Reusable code – Does the programmer follow the patterns of the design so that the code is reusable?

o Documentation – Does the programmer write internal and external documentations which are clear, crisp, and understandable?

Characteristics of Good Programming

Unit 23 4

The Techniques of Unit Testing

Unit testing is an integral part of Implementation Phase.

The unit testing process has two techniques:

o Static Testing

o Dynamic Testing

Unit 23 5

Static Testing

Static Testing does not require the system to be executed.

1. It checks/reviews Software Requirements Specification, Design documents (both architectural and detailed design), the program source code.

2. It checks for traceability. 3. It checks for the coding standards and naming

conventions. 4. It checks whether the design methodology follows

the OO principles.5. It checks programs for the unused or overused

program segments or variables.

Unit 23 6

Dynamic Testing

Dynamic Testing requires the system to be executed.

1. It checks the prototypes and the program source code.

2. It checks for logical errors. 3. It checks for data validation (what will happen if the

age in the input screen is given a negative integer?).

4. It checks non – functional characteristics such as performance, reliability, scalability, security etc.

Unit 23 7

Now we list the corresponding java code of the java templates of the design.

There are two java files and one html file:

o Account.java

o Customer.java and

o Bank.html.

Coding

Unit 23 8

public class Account{private int balance;public Account(int qty) {

balance = qty;}public void withDraw(Customer customer) {

if ( balance > 0){balance -= 50;customer.tellResult("Thanks for your custom-- " +"come back

soon.");}customer.tellResult("Sorry -- your balance is nil."+" Want to depositing

money?");}public void deposit(Customer customer) {

balance += 50;customer.tellResult("Thanks for depositing in our bank.");

}public int getBalance( ) {

return balance;}

}

Account.java

Unit 23 9

import java.applet.*;import java.awt.*;import java.awt.event.*;

public class Customer extends Applet implements ActionListener{

private final static int INITIAL_BAL = 500;private Button theWithDrawButton;private Button theDepositButton;private TextField theBalance;private TextField theMessage;private Account account = new Account ( INITIAL_BAL );public void init( ){

setLayout( new GridLayout(3, 1));theWithDrawButton = new Button( "Withdraw" );theDepositButton = new Button( "Deposit" );theBalance = new TextField( 10 );theMessage = new TextField( 64 );Panel north = new Panel( );north.setLayout(new FlowLayout( ));north.add(theWithDrawButton);north.add(theDepositButton);add(north);

Panel center = new Panel( );center.setLayout(new FlowLayout( ));center.add(new Label("Your Balance: "));center.add(theBalance);theBalance.setText(new String(new Integer(INITIAL_BAL).toString()));add(center);

Panel south = new Panel( );south.setLayout(new FlowLayout( ));south.add(new Label("Message: "));south.add(theMessage);add(south);

theWithDrawButton.addActionListener(this);theDepositButton.addActionListener(this);

}

Customer.java

Unit 23 10

public void actionPerformed( ActionEvent ae ){

Object source = ae.getSource( );

if (source == theWithDrawButton){account.withDraw(this);theBalance.setText("" +new String(new

nteger(account.getBalance()).toString()));}else if (source == theDepositButton){

account.deposit(this);theBalance.setText(""+new String(new

Integer(account.getBalance()).toString()));}

}public void tellResult(String msg){

theMessage.setText(msg);}

}

Customer.java - contd

Unit 23 11

<HTML>

<HEAD>

<TITLE>This is a Banking Software </TITLE>

</HEAD>

<BODY>

<H1>Welcome to <I>Riyadh Bank</I>

<BR>

This is Paul Manuel's Account

</H1>

<H4>you have an initial deposit of 500 riyals.

<HR>

To withdraw money, just press Withdraw.

To deposit money, just press Deposit

<HR></H4>

<APPLET CODE=Customer WIDTH=500 HEIGHT=150>

</APPLET>

</BODY>

</HTML>

Bank.html

Unit 23 12

Exercises

1. Write a java program using SUN coding standard.

2. Write a java program using Microsoft coding standard.

3. What is Hungarian notation?