Restore

PastAssignments/Assignment4/Assignment4_2230026071/Question6/.classpath

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+<?xml version="1.0" encoding="UTF-8"?>
+<classpath>
+	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER">
+		<attributes>
+			<attribute name="module" value="true"/>
+		</attributes>
+	</classpathentry>
+	<classpathentry kind="src" path="src"/>
+	<classpathentry kind="output" path="bin"/>
+</classpath>

PastAssignments/Assignment4/Assignment4_2230026071/Question6/.project

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+<?xml version="1.0" encoding="UTF-8"?>
+<projectDescription>
+	<name>Question6</name>
+	<comment></comment>
+	<projects>
+	</projects>
+	<buildSpec>
+		<buildCommand>
+			<name>org.eclipse.jdt.core.javabuilder</name>
+			<arguments>
+			</arguments>
+		</buildCommand>
+	</buildSpec>
+	<natures>
+		<nature>org.eclipse.jdt.core.javanature</nature>
+	</natures>
+</projectDescription>

PastAssignments/Assignment4/Assignment4_2230026071/Question6/.settings/org.eclipse.core.resources.prefs

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+eclipse.preferences.version=1
+encoding/<project>=UTF-8

PastAssignments/Assignment4/Assignment4_2230026071/Question6/src/Base.java

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+
+public class Base implements Learnable{
+	//instance variables
+	private String code;
+	private String title;
+	
+	//constructor
+	public Base(String code, String title) {
+		this.code = code;
+		this.title = title;
+	}
+	
+	//methods
+	@Override
+	public String getCode() {return this.code;}
+	
+	@Override
+	public String getTitle() {return this.title;}
+	
+	@Override
+	public Base getPreRequisite() {return Base.this;}
+	
+	//test
+	public static void testBase() {
+		Base b = new Base("DS1001", "EntryCourse");
+		System.out.println(b.getCode() == "DS1001");
+		System.out.println(b.getTitle() == "EntryCourse");
+		System.out.println(b.getPreRequisite() == b);
+	}
+}

PastAssignments/Assignment4/Assignment4_2230026071/Question6/src/Course.java

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+
+public abstract class Course implements Learnable{
+	//instance variables
+	private String code;
+	private String title;
+	private Learnable preRequisite;
+	
+	//constructor
+	public Course(String code, String title, Learnable preRequisite) {
+		//test if preRequisite satisfied the condition
+		if(preRequisite != null && (preRequisite instanceof MajorRequired || preRequisite instanceof Base)) {
+			this.code = code;
+			this.title = title;
+			this.preRequisite = preRequisite;
+		}
+		else {
+			System.out.println("pre-requisite course cannot null!");
+			return;
+		}
+	}
+	
+	//methods
+	@Override
+	public String getCode() {return this.code;}
+	
+	@Override
+	public String getTitle() {return this.title;}
+	
+	@Override
+	public Learnable getPreRequisite() {return this.preRequisite;}
+	
+	public abstract boolean isRequired();
+	
+	//test
+	public static void testCourse() {
+		// Since we cannot create any Course object, the testCourse method of the Course class must be empty.
+	}
+}

PastAssignments/Assignment4/Assignment4_2230026071/Question6/src/Learnable.java

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+
+public interface Learnable {
+	public String getCode();
+	public String getTitle();
+	public Learnable getPreRequisite();
+}

PastAssignments/Assignment4/Assignment4_2230026071/Question6/src/MajorElective.java

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+
+public class MajorElective extends Course{
+	//constructor
+	public MajorElective(String code, String title, Learnable preRequisite) {
+		super(code, title, preRequisite);
+	}
+	
+	//method
+	@Override
+	public boolean isRequired() {return true;}
+	
+	//test
+	public static void testMajorElective() {
+		// Create a Base object
+		Base b = new Base("DS1001","EntryCourse");
+		// Create a first MajorRequired object with the base course as pre-requisite
+		MajorRequired mr1 = new MajorRequired("DS200X","OOP",b);
+		// Create a MajorElective object with the major required course as pre-requisite
+		MajorElective me1 = new MajorElective("DS300X","Data Mining",mr1);
+		// Test mr1
+		System.out.println(mr1.getCode() == "DS200X");
+		System.out.println(mr1.getTitle() == "OOP");
+		System.out.println(mr1.getPreRequisite() == b);
+		// Test mr2
+		System.out.println(me1.getCode() == "DS300X");
+		System.out.println(me1.getTitle() == "Data Mining");
+		System.out.println(me1.getPreRequisite() == mr1);
+	}
+}

PastAssignments/Assignment4/Assignment4_2230026071/Question6/src/MajorRequired.java

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+
+public class MajorRequired extends Course{
+	//constructor
+	public MajorRequired(String code, String title, Learnable preRequisite) {
+		super(code, title, preRequisite);
+	}
+	
+	//method
+	@Override
+	public boolean isRequired() {return true;}
+	
+	//test
+	public static void testMajorRequired() {
+		// Create a Base object
+		Base b = new Base("DS1001","EntryCourse");
+		// Create a first MajorRequired object with the base course as pre-requisite
+		MajorRequired mr1 = new MajorRequired("DS200X","OOP",b);
+		// Create a second MajorRequired object with the first major required course as pre-requisite
+		MajorRequired mr2 = new MajorRequired("DS300X","Data Mining",mr1);
+		// Test mr1
+		System.out.println(mr1.getCode() == "DS200X");
+		System.out.println(mr1.getTitle() == "OOP");
+		System.out.println(mr1.getPreRequisite() == b);
+		// Test mr2
+		System.out.println(mr2.getCode() == "DS300X");
+		System.out.println(mr2.getTitle() == "Data Mining");
+		System.out.println(mr2.getPreRequisite() == mr1);
+	}
+}

PastAssignments/Assignment4/Assignment4_2230026071/Question6/src/ManyCourses.java

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+import java.util.ArrayList;
+
+public class ManyCourses {
+	//instance variable
+	private ArrayList<Learnable> courses;
+	
+	//constructor
+	public ManyCourses() {
+		this.courses = new ArrayList<Learnable>();
+	}
+	
+	//methods
+	public void addCourse(Learnable c) {
+		this.courses.add(c);
+	}
+	
+	public void listCourses() {
+		for(int i = 0; i < courses.size(); ++i) {
+			Learnable c = (Learnable) courses.get(i); //downcast from object to Learnable
+			System.out.println(c.getCode() + " ," + c.getTitle());
+		}
+	}
+	
+	//test
+	public static void testManyCourses() {
+		Base b = new Base("DS1001","EntryCourse");
+		MajorRequired mr1 = new MajorRequired("DS200X","OOP",b);
+		MajorElective me1 = new MajorElective("DS300X","Data Mining",mr1);
+		ManyCourses mc = new ManyCourses();
+		mc.addCourse(b);
+		mc.addCourse(mr1);
+		mc.addCourse(me1);
+		mc.listCourses();
+	}
+}

PastAssignments/Assignment4/Assignment4_2230026071/Question6/src/Start.java

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+
+public class Start {
+	public static void main(String[] args) {
+		Course.testCourse();
+		MajorRequired.testMajorRequired();
+		MajorElective.testMajorElective();
+		Base.testBase();
+		ManyCourses.testManyCourses();
+	}
+}