Lab 4

lab/lab4/Question4/Chicken.java

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+/*
+ * Author: CHEN Yongyuan (Walter) 1930006025 from OOP(1007)
+ * Date: 2022-03-17
+ * Description: This is the Chicken class.
+ */
+
+public class Chicken {
+	/*
+	 * The weight instance variable indicates the current weight of the chiken.
+	 */
+	private double weight;
+
+	/*
+	 * The sleeping instance variable indicates whether the chicken is currently
+	 * sleeping or not.
+	 * It is intially sleeping.
+	 */
+	private boolean sleeping;
+
+	/**
+	 * Constructor: Chicken(double weight)
+	 * 
+	 * @param weight
+	 *               The weight of the chicken.
+	 *               The weight must be greater than 0. If the weight is less than
+	 *               0, the weight is set to 0.
+	 */
+	public Chicken(double weight) {
+		if (weight < 0) {
+			this.weight = 0;
+		} else {
+			this.weight = weight;
+		}
+
+		// initially the chicken is sleeping
+		this.sleeping = true;
+	}
+
+	/**
+	 * Getter method: getWeight()
+	 *
+	 * @return The weight of the chicken.
+	 */
+	public double getWeight() {
+		return this.weight;
+	}
+
+	/**
+	 * Getter method: isSleeping()
+	 *
+	 * @return true if the chicken is sleeping, false otherwise.
+	 */
+	public boolean isSleeping() {
+		return this.sleeping;
+	}
+
+	/**
+	 * Makes the chicken fall asleep. Or do nothing if the chicken is already
+	 * sleeping.
+	 * 
+	 * @return void
+	 */
+	public void fallAsleep() {
+		this.sleeping = true;
+	}
+
+	/**
+	 * Makes the chicken wake up. Or do nothing if the chicken is already awake.
+	 * 
+	 * @return void
+	 */
+	public void wakeUp() {
+		this.sleeping = false;
+	}
+
+	/**
+	 * Tests function.
+	 */
+	public static void testChicken() {
+		Chicken c = new Chicken(2.3);
+		System.out.println(c.getWeight() == 2.3);
+		System.out.println(c.isSleeping() == true);
+		c.wakeUp();
+		System.out.println(c.isSleeping() == false);
+		c.wakeUp(); // should do nothing because the chicken is already awake
+		System.out.println(c.isSleeping() == false);
+		c.fallAsleep();
+		System.out.println(c.isSleeping() == true);
+		c.fallAsleep(); // should do nothing because the chicken is already sleeping
+		System.out.println(c.isSleeping() == true);
+	}
+}