73 lines
1.7 KiB
Java
73 lines
1.7 KiB
Java
/*
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* Author: CHEN Yongyuan (Walter) 1930006025 from OOP(1007)
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* Date: 2022-04-14
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* Description: This is the Dot class inherited from Shape class.
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*/
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public class Dot extends Shape {
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/**
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* Constructor.
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*
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* @param x the x coordinate of the dot
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* @param y the y coordinate of the dot
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*/
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public Dot(double x, double y) {
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super(x, y);
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}
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/**
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* Calculates the dot's area.
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*
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* @return the area of the dot
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*/
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public double area() {
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return 0;
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}
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/**
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* Resize method of Dot throw an CannotResizeException with message "Cannot
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* resize a dot!"
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*
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* @param newSize the new size of the dot
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* @throws CannotResizeException the exception
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*/
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@Override
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public void resize(double newSize) throws CannotResizeException {
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throw new CannotResizeException("Cannot resize a dot!");
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}
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/**
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* Test.
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*/
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public static void testDot() {
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Dot d = new Dot(1.2, 3.4);
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// getX, getY, and move are inherited from Shape.
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// area and resize come from Dot itself.
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System.out.println(d.getX() == 1.2);
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System.out.println(d.getY() == 3.4);
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System.out.println(d.area() == 0.0);
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// Move the dot. The area does not change.
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d.move(7.8, 9.0);
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System.out.println(d.getX() == 9.0);
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System.out.println(d.getY() == 12.4);
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System.out.println(d.area() == 0.0);
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// Resize the dot. An exception is thrown, caught, and tested.
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try {
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d.resize(12.3);
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} catch (Exception ex) {
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System.out.println(ex.getMessage() == "Cannot resize a dot!");
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}
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// The area and position do not change.
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System.out.println(d.getX() == 9.0);
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System.out.println(d.getY() == 12.4);
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System.out.println(d.area() == 0.0);
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try {
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d.resize(12.3);
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} catch (CannotResizeException ex) {
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System.out.println(ex.getMessage() == "Cannot resize a dot!");
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}
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}
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}
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