Singleton Pattern - Ball Selector

Creates a Ball class as a singleton to ensure that there is only one instance of each of the different colors.

Lab 11/Lab 11.iml

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+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4">
+  <component name="NewModuleRootManager" inherit-compiler-output="true">
+    <exclude-output />
+    <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />
+    </content>
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+  </component>
+</module>

Lab 11/src/Ball.java

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+/* Ball class modification of a Singleton object
+ */
+
+import java.util.*;
+
+public class Ball{
+    private static HashMap<String, Ball> colors = new HashMap<String, Ball>();
+    private String color;
+    private int bounces;
+    private int rolls;
+
+    /* Ball constructor
+     */
+    public Ball(String c){
+        this.color = c;
+        this.bounces = 0;
+        this.rolls = 0;
+        colors.put(c, this);
+    }
+    /* Accceses the hashmap and checks to see if the object already exists, otherwise constructs the object and returns it to be inserted.
+     *
+     * @param c the key of the object to be checked.
+     * @return the object which to be modified.
+     */
+    public static Ball getInstance(String c) {
+
+        if (colors.containsKey(c)) {
+            return colors.get(c);
+        }
+        else{
+            return new Ball(c);
+        }
+    }
+
+    /* Increment the bounce count of a ball
+     *
+     */
+    public void bounce(){
+        this.bounces += 1;
+    }
+
+    /* Increment the roll count of a ball
+     */
+    public void roll(){
+        this.rolls += 1;
+    }
+
+    /* String representation of a ball object
+     * @return returns a string detailing the current status of the users ball
+     */
+    @Override
+    public String toString(){
+        return String.format("%s Ball:\n--------\nRolls: %d\nBounces: %d\n",
+                this.color,
+                this.rolls,
+                this.bounces);
+    }
+}

Lab 11/src/CheckInput.java

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+import java.util.Scanner;
+
+/**
+ * Static functions used to check console input for validity.
+ *
+ * Use:	Place CheckInput class in the same project folder as your code.
+ *	Call CheckInput functions from your code using "CheckInput."
+ *
+ * Example:  int num = CheckInput.getInt();
+ *
+ * @author Shannon Cleary 2020
+ */
+public class CheckInput {
+
+    /**
+     * Checks if the inputted value is an integer.
+     * @return the valid input.
+     */
+    public static int getInt() {
+        Scanner in = new Scanner( System.in );
+        int input = 0;
+        boolean valid = false;
+        while( !valid ) {
+            if( in.hasNextInt() ) {
+                input = in.nextInt();
+                valid = true;
+            } else {
+                in.next(); //clear invalid string
+                System.out.println( "Invalid Input." );
+            }
+        }
+        return input;
+    }
+
+    /**
+     * Checks if the inputted value is an integer and
+     * within the specified range (ex: 1-10)
+     * @param low lower bound of the range.
+     * @param high upper bound of the range.
+     * @return the valid input.
+     */
+    public static int getIntRange( int low, int high ) {
+        Scanner in = new Scanner( System.in );
+        int input = 0;
+        boolean valid = false;
+        while( !valid ) {
+            if( in.hasNextInt() ) {
+                input = in.nextInt();
+                if( input <= high && input >= low ) {
+                    valid = true;
+                } else {
+                    System.out.println( "Invalid Range." );
+                }
+            } else {
+                in.next(); //clear invalid string
+                System.out.println( "Invalid Input." );
+            }
+        }
+        return input;
+    }
+    /**
+     * Checks if the inputted value is a non-negative integer.
+     * @return the valid input.
+     */
+    public static int getPositiveInt( ) {
+        Scanner in = new Scanner( System.in );
+        int input = 0;
+        boolean valid = false;
+        while( !valid ) {
+            if( in.hasNextInt() ) {
+                input = in.nextInt();
+                if( input >= 0 ) {
+                    valid = true;
+                } else {
+                    System.out.println( "Invalid Range." );
+                }
+            } else {
+                in.next(); //clear invalid string
+                System.out.println( "Invalid Input." );
+            }
+        }
+        return input;
+    }
+
+    /**
+     * Checks if the inputted value is a double.
+     * @return the valid input.
+     */
+    public static double getDouble() {
+        Scanner in = new Scanner( System.in );
+        double input = 0;
+        boolean valid = false;
+        while( !valid ) {
+            if( in.hasNextDouble() ) {
+                input = in.nextDouble();
+                valid = true;
+            } else {
+                in.next(); //clear invalid string
+                System.out.println( "Invalid Input." );
+            }
+        }
+        return input;
+    }
+
+    /**
+     * Takes in a string from the user.
+     * @return the inputted String.
+     */
+    public static String getString() {
+        Scanner in = new Scanner( System.in );
+        String input = in.nextLine();
+        return input;
+    }
+
+    /**
+     * Takes in a yes/no from the user.
+     * @return true if yes, false if no.
+     */
+    public static boolean getYesNo(){
+        boolean valid = false;
+        while( !valid ) {
+            String s = getString();
+            if( s.equalsIgnoreCase("yes") || s.equalsIgnoreCase("y") ) {
+                return true;
+            } else if( s.equalsIgnoreCase("no") || s.equalsIgnoreCase("n") ) {
+                return false;
+            } else {
+                System.out.println( "Invalid Input." );
+            }
+        }
+        return false;
+    }
+}

Lab 11/src/Main.java

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+/*
+ * Alfredo Sequeida
+ * Diego Garcia
+ * 11/9/2021
+
+ * Group 5
+ * Lab 11
+ * This program takes user input and asks the user what they want to do with a ball.
+ * It then keep track of that action using a singleton-like Ball object.
+ */
+class Main {
+    public static void main(String[] args) {
+
+        boolean keepAsking = true;
+
+        while (keepAsking){
+            System.out.println("Choose a ball color. Type it in string format. (q to quit):");
+            String color = CheckInput.getString();
+            if (color.equals("q")){
+                keepAsking = false;
+                break;
+            }
+            System.out.println("1. Roll ball\n2. Bounce ball");
+            int option = CheckInput.getIntRange(1,2);
+
+            Ball ball = Ball.getInstance(color);
+
+            switch(option){
+                case (1):
+                    ball.roll();
+                    break;
+                case (2):
+                    ball.bounce();
+                    break;
+            }
+
+            System.out.println(ball);
+        }
+    }
+}