slide เสริมวิชา JAVA จากอาจารย์ฝนครับ Applet 4 class_composition

1. การออกแบบ Class แบบ Composition ssc
การออกแบบ Class แบบ Composition คือ ...........................................................................................................................
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Constructor method) ออกแบบไวเพื่อ ........................................................................................................................
“get” method) ) ออกแบบไวเพื่อ ........................................................................................................................
“set” method) ) ออกแบบไวเพื่อ ........................................................................................................................
Facilities method)) ออกแบบไวเพื่อ ........................................................................................................................
ตัวอยางการออกแบบ Class แบบ Composition เพื่อเก็บขอมูลการลงทะเบียน
จากรูป สามารถอธิบายไดวา ..................................................................................................................................................
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Class Subject
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Class Student
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Class Register
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2. ตัวอยางการสราง Class แบบ Composition เพื่อเก็บขอมูลการลงทะเบียน
Class Subject
ขั้นตอนที่ 1 สราง Class Subject ขึ้นมา
public class Subject {
}
ขั้นตอนที่ 2 สราง Attribute ตางๆ ตามที่ไดออกแบบไว
! private String SubjectCode;
! private String SubjectName;
! private int SubjectCredit;
ขั้นตอนที่ 3 สราง Constructor method ตางๆ ตามที่ไดออกแบบไว
! public Subject() {
! ! setSubjectCode("");
! ! setSubjectName("");
! ! setSubjectCredit(0);
! }
! public Subject(String Code, String Name, int Credit) {
! ! setSubjectCode(Code);
! ! setSubjectName(Name);
! ! setSubjectCredit(Credit);
! }
Constructor method 2 method นี้มีไวเพื่อ ............................................................................................................................
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ขั้นตอนที่ 4 สราง “set” method ตางๆ ตามที่ไดออกแบบไว
! public void setSubjectCode(String Code) {
! ! SubjectCode = Code;
! }
! public void setSubjectName(String Name) {
! ! SubjectName = Name;
! }
! public void setSubjectCredit(int Credit) {
! ! SubjectCredit = Credit;
! }
“set” method 3 method นี้มีไวเพื่อ ........................................................................................................................................
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ขั้นตอนที่ 5 สราง “get” method ตางๆ ตามที่ไดออกแบบไว
! public String getSubjectCode() {
! ! return(SubjectCode);
! }
! public String getSubjectName() {
! ! return(SubjectName);
! }
! public int getSubjectCredit() {
! ! return(SubjectCredit);
! }
“get” method 3 method นี้มีไวเพื่อ .......................................................................................................................................
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ขั้นตอนที่ 6 สราง Facilities method ตางๆ ตามที่ไดออกแบบไว
! public String toString() {
! ! String str = "";
! ! str = getSubjectCode()+" "+getSubjectName()+" ";
! ! str += getSubjectCredit();
! ! return(str);
! }
Facilities method นี้ มีชื่อวา ........................................ มีไวเพื่อ ............................................................................................
.............................................................................................................................................................................................
ขั้นตอนที่ 7 ทำการ Compile
โดยใชคำสั่ง ..........................................................................................................................................................................
ผลลัพธที่ได ..........................................................................................................................................................................
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3. Class Student
ขั้นตอนที่ 1 .................................................................................................................
public class Student {
}
ขั้นตอนที่ 2 .................................................................................................................
! String StudentCode;
! String StudentName;
! String StudentSurName;
ขั้นตอนที่ 3 .................................................................................................................
! public Student() {
! ! setStudentCode("");
! ! setStudentName("");
! ! setStudentSurName("");
! }
! public Student(String Code, String Name, String SurName) {
! ! setStudentCode(Code);
! ! setStudentName(Name);
! ! setStudentSurName(SurName);
! }
Constructor method 2 method นี้มีไวเพื่อ ............................................................................................................................
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ขั้นตอนที่ 4 .................................................................................................................
! public void setStudentCode(String Code) {
! ! StudentCode = Code;
! }
! public void setStudentName(String Name) {
! ! StudentName = Name;
! }
! public void setStudentSurName(String SurName) {
! ! StudentSurName = SurName;
! }
“set” method 3 method นี้มีไวเพื่อ ........................................................................................................................................
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ขั้นตอนที่ 5 .................................................................................................................
! public String getStudentCode() {
! ! return(StudentCode);
! }
! public String getStudentName() {
! ! return(StudentName);
! }
! public String getStudentSurName() {
! ! return(StudentSurName);
! }
“get” method 3 method นี้มีไวเพื่อ .......................................................................................................................................
.............................................................................................................................................................................................
ขั้นตอนที่ 6 .................................................................................................................
! public String toString() {
! ! String str = "";
! ! str = getStudentCode()+" "+getStudentName()+" ";
! ! str += getStudentSurName();
! ! return(str);
! }
Facilities method นี้ มีชื่อวา ........................................ มีไวเพื่อ ............................................................................................
.............................................................................................................................................................................................
ขั้นตอนที่ 7 ทำการ Compile
โดยใชคำสั่ง ..........................................................................................................................................................................
ผลลัพธที่ได ..........................................................................................................................................................................
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4. Class Register
ขั้นตอนที่ 1 .................................................................................................................
public class Register {
}
ขั้นตอนที่ 2 .................................................................................................................
! private Student std;
! private Subject sub[];
! private int max, count = -1;
ขั้นตอนที่ 3 .................................................................................................................
! public Register() {
! ! std = new Student();
! ! max = 0;
! }
! public Register(Student std, int n) {
! ! this.std = std;
! ! max = n;
! ! createSubject(max);
! }
Constructor method 2 method นี้มีไวเพื่อ ............................................................................................................................
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ขั้นตอนที่ 4 .................................................................................................................
! public void setStudent(Student std) {
! ! this.std = std;
! }
! public void setSubject(Subject sub) {
! ! this.sub[++count] = sub;
! }
! public void setSubject(Subject sub, int n) {
! ! this.sub[n] = sub;
! }
“set” method 3 method นี้มีไวเพื่อ ........................................................................................................................................
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ขั้นตอนที่ 5 .................................................................................................................
! public String getStudent() {
! ! return(std.toString());
! }
! public String getSubject(int n) {
! ! return(sub[n].toString());
! }
“get” method 3 method นี้มีไวเพื่อ .......................................................................................................................................
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ขั้นตอนที่ 6 .................................................................................................................
! private void createSubject(int n) {
! ! sub = new Subject[n];
! }
Facilities method นี้ มีชื่อวา ........................................ มีไวเพื่อ ............................................................................................
.............................................................................................................................................................................................
ขั้นตอนที่ 7 ทำการ Compile
โดยใชคำสั่ง ..........................................................................................................................................................................
ผลลัพธที่ได ..........................................................................................................................................................................
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5. การทดสอบการทำงานของ Class แบบ Composition
1) สราง testComposition.html เอาไวสำหรับ Run
2) สราง testComposition.java เอาไวทดสอบ
ตัวอยางหนาจอการทำงาน
testComposition.html
<html>
! <body>
<h1>Test Composition: Registration Program</h1>
<h3>Create by: 5366261111 Supaporn Simcharoen IT1-RC</h3>
! ! <applet code="testComposition.class" height="250" width="750">
! ! </applet>
! </body>
</html>
testComposition.java
ขั้นตอนที่ 1 สราง Class พรอมกับ import package ที่ตองใช และสราง Method ที่นาจะมี
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
public class testComposition extends JApplet implements ActionListener{
! public void init(){
! }
! public void actionPerformed(ActionEvent event){
! }
}
ทำไมตอง extends JApplet ..................................................................................................................................................
ทำไมตอง implements ActionListener ..................................................................................................................................
method init มีไวเพื่อ .............................................................................................................................................................
method actionPerformed มีไวเพื่อ .......................................................................................................................................
ขั้นตอนที่ 2 สรางหนาจอการทำงาน
! Container c;
!
! JLabel stdCodeLabel, stdNameLabel, stdSurnameLabel;
! JTextField stdCodeText, stdNameText, stdSurnameText, stdText;
! JButton addStdBtn;
! JLabel subCodeLabel, subNameLabel, subCreditLabel;
! JTextField subCodeText, subNameText, subCreditText;
! JButton addSubBtn;
! JTextArea subTextArea;
! JScrollPane subScroll;
!
! JButton saveBtn, cancleBtn;
! public void init(){
! ! initGui();
! }
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6. ! public void initGui(){
! ! c = getContentPane();
! ! c.setLayout( new FlowLayout());
! !
! ! stdCodeLabel = new JLabel("Enter Student Code:");
! ! c.add(stdCodeLabel);
! ! stdCodeText = new JTextField(6);
! ! c.add(stdCodeText);
! ! stdNameLabel = new JLabel("Name:");
! ! c.add(stdNameLabel);
! ! stdNameText = new JTextField(10);
! ! c.add(stdNameText);! !
! ! stdSurnameLabel = new JLabel("Surname:");
! ! c.add(stdSurnameLabel);
! ! stdSurnameText = new JTextField(10);
! ! c.add(stdSurnameText);!
! ! addStdBtn = new JButton("Add Student");
! ! addStdBtn.addActionListener(this);
! ! c.add(addStdBtn);
! !
!
!
!
!
stdText = new JTextField(60);
stdText.setEditable(false);
Note :: .....................................................................
! ! c.add(stdText);!
! !
! ! subCodeLabel = new JLabel("Enter Subject Code:");
! ! c.add(subCodeLabel);
! ! subCodeText = new JTextField(6);
! ! c.add(subCodeText);! !
! !
! ! subNameLabel = new JLabel("Name:");
! ! c.add(subNameLabel);
! ! subNameText = new JTextField(17);
! ! c.add(subNameText);! !
! !
! ! subCreditLabel = new JLabel("Credit:");
! ! c.add(subCreditLabel);
! ! subCreditText = new JTextField(5);
! ! c.add(subCreditText);! ! !
! ! addSubBtn = new JButton("Add Subject");
! ! addSubBtn.setEnabled(false);
! ! addSubBtn.addActionListener(this);
! ! c.add(addSubBtn);
! !
! ! subTextArea = new JTextArea(5,60);
! ! subTextArea.setEditable(false);
! ! subScroll = new JScrollPane(subTextArea);
! ! c.add(subScroll);! !
! !
! ! saveBtn = new JButton(" Save ");
! ! saveBtn.setEnabled(false);
! ! saveBtn.addActionListener(this);
! ! c.add(saveBtn);
! !
! ! cancleBtn = new JButton(" Cancle ");
! ! cancleBtn.setEnabled(false);
! ! cancleBtn.addActionListener(this);
! ! c.add(cancleBtn);! !
! }
ขั้นตอนที่ 3 ทดลอง Compile และ Run
วิธีในการ Run คือ .................................................................................................................................................................
ขั้นตอนที่ 4 สราง Object Register เพื่อทดสอบการทำงาน
! Register reg; Note :: ................................................................
! int count = 0;
...............................................................................
!
!
public void init(){
! initGui();
...............................................................................
!
!
!
}
reg = new Register(new Student(), 5);
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ขั้นตอนที่ 5 ทดลอง Compile และ Run อีกครั้ง
...............................................................................
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7. ขั้นตอนที่ 6 ใสการรองรับการกระทำกับ ปุมตางๆ ทั้งหมด
ที่ปุม Add Student
! ! if (event.getSource() == addStdBtn) {
! ! ! Student std = new Student(stdCodeText.getText(), stdNameText.getText(),
stdSurnameText.getText());
! ! ! stdText.setText(std.toString());
! ! ! reg.setStudent(std);
! ! ! addStdBtn.setEnabled(false);
! ! ! addSubBtn.setEnabled(true);
! ! ! saveBtn.setEnabled(true);
! ! ! cancleBtn.setEnabled(true);
! ! ! stdCodeText.setText("");
! ! ! stdNameText.setText("");
! ! ! stdSurnameText.setText("");! ! ! !
! ! }
Note ::
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.............................................................................................................................................................................................
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ที่ปุม Add Subject
! ! else if (event.getSource() == addSubBtn) {
! ! ! Subject sub = new Subject(subCodeText.getText(), subNameText.getText(),
Integer.parseInt(subCreditText.getText()));
! ! ! subTextArea.append(sub.toString()+"n");
! ! ! reg.setSubject(sub, count);
! ! ! count++;
! ! ! if (count == 5 ){
! ! ! ! addSubBtn.setEnabled(false);
! ! ! }
! ! ! subCodeText.setText("");
! ! ! subNameText.setText("");
! ! ! subCreditText.setText("");
! ! }
Note ::
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ที่ปุม Save
! ! else if (event.getSource() == saveBtn) {
! ! ! String output="";
! ! ! output = "Student :" + reg.getStudent();
! ! ! output += "nSubject:n";
! ! ! for(int n = 0 ; n < count; n++)
! ! ! ! output += reg.getSubject(n) + "n";
! ! ! JOptionPane.showMessageDialog(null, output,"Registration
Data",JOptionPane.INFORMATION_MESSAGE);
! ! ! resetAll();
! ! }
Note ::
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.............................................................................................................................................................................................
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ที่ปุม Cancle
! ! else if (event.getSource() == cancleBtn) {
! ! ! resetAll();
! ! }
Note ::
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8. Method resetAll
! public void resetAll() {
! ! stdCodeText.setText("");
! ! stdNameText.setText("");
! ! stdSurnameText.setText("");
! ! stdText.setText("");
! ! addStdBtn.setEnabled(true);
! !
! ! subCodeText.setText("");
! ! subNameText.setText("");
! ! subCreditText.setText("");
! ! addSubBtn.setEnabled(false);
! ! subTextArea.setText("");
! !
! ! saveBtn.setEnabled(false);
! ! cancleBtn.setEnabled(false);
! !
! ! count = 0;
! }
Note ::
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การบาน
1) ตัวแปร count ที่อยูใน Class testComposition มีไวเพื่ออะไร
2) ใหยกเลิกการใชงานตัวแปร count ที่ Class testComposition และใหไปใชตัวแปร count ใน Class Register แทน
3) ใหเพิ่มการทำงานของโปรแกรมโดยใหสามารถคนหา(Search) แกไข(Edit) และลบ(Delete) Subject ได
ตัวอยางหนาจอการทำงาน
ตัวอยางการสราง Confirm Dialog
int ans = JOptionPane.showConfirmDialog(null, "Delete?","Confirm",JOptionPane.YES_NO_OPTION);
if (ans == 0) {
//ในกรณีที่ผูใชกดปุม Yes แลว ans จะมีคาเทากับ 0
}
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