java programming, 3e concepts and techniques chapter 1 an introduction to java and program design

Java Programming, 3eConcepts and Techniques

Chapter 1An Introduction to

Java and Program Design

2Chapter 1: An Introduction to Java and Program Design

Chapter Objectives

• Describe characteristics of Java

• Explain the uses of Java and identify types of Java programs

• Identify the phases in the program development life cycle

• Define programs, programming, and applications

• Read, explain, and create a class diagram


Chapter Objectives

• Read, explain, and create an event diagram

• Explain object-oriented programming (OOP) and object-oriented design (OOD)

• Define the terms objects, attributes, methods, and events

• Define and explain encapsulation, inheritance, and polymorphism


Chapter Objectives

• Describe rapid application development (RAD)

• Identify key components of the Java Software Development Kit (SDK)


Introduction

• A program is a step-by-step series of instructions for a computer

• Computer programming is the process of writing these instructions

• Programmers, or developers, design and write programs using a programming language or development tool

• Java is a programming language that provides the structure for efficient and economical programs


What Is Java?

• High-level language

• Object-oriented– Data and operations are packaged into a

single unit called an object

• Basic syntax derived from C, C++, and Smalltalk– Designed by a team from Sun Microsystems

led by James Gosling in the early 1990’s


What Is Java?

• Parsimonious– Compatible with older versions

• Robust– Strongly typed and incorruptible data

• Secure– Protection against misuse of code

• Portable– Platform-independent


Java Program Types

• Console and Windowed applications

• Applets

• Servlets

• Web Services

• JavaBeans


Console Applications

• Stand-alone programs using a command-line interface


Windowed Applications

• Stand-alone programs using a graphical user interface (GUI)


Applets

• Client-side programs executed as part of a displayed Web page


Servlets

• Server-side programs hosted and run on a Web server

• Used in conjunction with Java Server Pages (JSP) to provide sophisticated server-side logic

• Enable connections to server databases through Java Database Connectivity (JDBC)


Servlets


Web Services

• Services receive information requests over the Web and return the requested data


JavaBeans• Reusable software components


Programming a Computer

• Companies need developers to build general application software packages

• Custom applications are built for specific needs

• Existing programs need maintenance, monitoring, and upgrades

• New applications will be needed due to emerging technologies


Program Development Cycle


Phase 1 – Analyze the Requirements• Verify that the requirements are clear and

complete

• Evaluate the problem to determine that it is solvable using a program

• List the required input and output data

• Determine whether the input data is available for testing


Phase 1 – Analyze the Requirements• Ensure that a solution, or algorithm, can

be developed with the information provided in the requirements

• Verify the user interface specifications


Phase 2 – Design the Solution

• Develop a logical model that illustrates the sequence of steps you will take to solve the problem

• Use design tools such as storyboards, class diagrams, flowcharts, and pseudocode to outline the logic of the program



• Storyboards are sketches of the user interface



• Class Diagrams illustrate the attributes and methods of a class of objects– Attributes define the characteristics of a class– Methods are instructions a class uses to

manipulate values, generate outputs, or perform actions



• Flowcharts graphically represent the logic used to develop an algorithm

• Control structures allow the programmer to specify the code that will execute only if a condition is met

• Flowcharts use pseudocode, English, or mathematical notation inside symbols to represent the steps of a solution



• Pseudocode is an English representation of how the program code should be written


Phase 3 – Validate the Design

• The programmer steps through the solution with test data

• The user agrees that the program design solves the problem put forth in the requirements

• The user verifies that the initial requirements document contains all necessary requirements


Phase 4 – Implement the Design

• Write the code that translates the design into a program

• Create the user interface

• Create comments within the code that explains the purpose of the code

• Unit testing– Test the code as it is written

• Test related code


Phase 4 – Implement the Design


Phase 5 – Test the Solution

• Create a test plan with test cases of sample input data and expected output

• Perform integration testing to ensure that components interact correctly

• Test boundary values

• Document any problems– If results are unsatisfactory, a new iteration of

the development cycle begins


Phase 6 – Document the Solution

• Requirements documents, program design documents, user interface documents, and documentation of the code

• Test cases and proof of successful completion of testing

• Program code should be archived electronically


Object-Oriented Programming and Design• Object-oriented programming

– Data and the code that operates on the data are packaged into a single unit called an object

• Object-oriented design– Identifies how objects interact with each other

to solve a problem


Object-Speak

• Aggregation– The concept of an object composed of

another object

• Generalization hierarchy– A tool displaying a hierarchy of classes,

including superclasses and subclasses

• Instance– A specific use of a class


Object-Speak

• Operation– Activity that reads or manipulates the data of an

object

• Message– Activates the code to perform one of the operations

• Trigger– Causes the message to be sent

• Event– The process of a trigger sending a message that

results in an operation


Object-Speak

• An event diagram graphically represents relationships among event and operations

• Useful for designing event-driven programs• Part of the Unified Modeling Language (UML)

– The UML provides a standardized model to describe object-oriented designs graphically

– The UML is a system of symbols to represent object behavior and program behavior


Encapsulation

• The process of hiding the implementation details of an object from its user

• The user is shielded from the system’s complexity

• Information hiding provides access to an object only through its messages

• Objects can be modified without requiring application modification


Inheritance

• An efficient way to reuse code by defining a subclass as an extension of another class

• The subclass inherits all the data and functions of the superclass

• The subclass has at least one attribute or method that differs from its superclass


Polymorphism

• Allows an instruction to be given to an object using a generalized command

• The same command will obtain different results depending on the object receiving the command

• The specific actions internal to the object are encapsulated from the user


Rapid Application Development

• Pre-built objects speed up program development


What Is the Java SDK?

• The Java Software Development Kit (SDK) is a programming package to develop Java applications

• The Java Runtime Environment (JRE) provides the tools to deploy Java applications


Features of the J2SE

• The Java Compiler– Converts code into bytecode

• The Java Virtual Machine – Contains an interpreter to execute the bytecode

• The Java API– The standard set of packages available in Java

• The Java Applet Viewer– Mini browser to display Java applets


Other Java Development Tools

• VATE (value-added text editor)– Color codes elements and numbers lines– Examples: TextPad, JCreator, JGrasp

• IDE (integrated development environment)– Builder tool to aid coding and debugging – Examples: Sun ONE Studio, JBuilder, Visual Age,

Simplicity

• Web server– Deploys servlets– Example: Tomcat


Chapter Summary

• Describe characteristics of Java

• Explain the uses of Java and identify types of Java programs

• Identify the phases in the program development life cycle

• Define programs, programming, and applications

• Read, explain, and create a class diagram


Chapter Summary

• Read, explain, and create an event diagram

• Explain object-oriented programming (OOP) and object-oriented design (OOD)

• Define the terms objects, attributes, methods, and events

• Define and explain encapsulation, inheritance, and polymorphism


Chapter Summary

• Describe rapid application development (RAD)

• Identify key components of the Java Software Development Kit (SDK)

Java Programming, 3eConcepts and Techniques

Chapter 1 Complete

java programming, 3e concepts and techniques chapter 1 an introduction to java and program design

Documents

program design slide

java programming

characteristics of java

uses of java

java program types console

types of java programs

chapter objectives

development tool java