Case Study: Creating a Class

• Team class

UML Diagram

UML Diagrams:

Constructors

• Constructor - Method used to perform operations on a newly created object

-typically used to initialize instance fields

• Every class needs a constructor. Java creates a 'default constructor' when no constructor is given.

• Default Constructor

Team.java

 1         /*
 2          * To change this license header, choose License Headers in Project Properties.
 3          * To change this template file, choose Tools | Templates
 4          * and open the template in the editor.
 5          */
 6         package worldseries;
 7         
 8         /**
 9          *
10          * @author student
11          */
12         public class Team
13         {
14            //These are the fields.
15            private int wins;
16            private int losses;
17            private String name;
18            //private double winningPercentage;
19            
20            //This is a constructor.
21            public Team(String n, int w, int l){
22               name = n;
23               wins = w;
24               losses = l;
25            }
26         
27            
28            public String getName(){
29               return name;
30            }
31            
32            public int getWins(){
33               return wins;
34            }
35            
36            public int getLosses(){
37               return losses;
38            }
39            
40            public double getWinningPercentage(){
41               double total = wins + losses;
42               return wins / total;
43            }
44            
45            public void printStats(){
46               System.out.println("Name: " + name);
47               System.out.println("Wins: " + wins);
48               System.out.println("Losses: " + losses);
49               System.out.println("WP: " + getWinningPercentage());
50               
51            }
52            
53            public void setWins(int w){
54               wins = w;
55            }
56            
57            public void setLosses(int l){
58               losses = l;
59            }
60         }
61  

WorldSeries.java

 1 /*
 2                  * To change this license header, choose License Headers in Project Properties.
 3                  * To change this template file, choose Tools | Templates
 4                  * and open the template in the editor.
 5  */
 6 package worldseries;
 7 
 8 /**
 9  *
10  * @author student
11  */
12 public class WorldSeries {
13 
14     /**
15      * @param args the command line arguments
16      */
17     public static void main(String[] args) {
18         Team cubs = new Team("Cubs", 92, 70);
19         Team nationals = new Team("Nationals", 97, 65);
20         Team padres = new Team("Indians", 102, 60);
21 
22         //Starting statistics
23         cubs.printStats();
24 
25         nationals.printStats();
26 
27         padres.printStats();
28 
29         System.out.println("Now entering the playoffs...");
30 
31         //cubs win, nationals lose, padres lose
32         //cubs win
33         cubs.setWins(cubs.getWins() + 1);
34 
35         //nationals lose
36         nationals.setLosses(nationals.getLosses() + 1);
37 
38         //padres lose
39         padres.setLosses(padres.getLosses() + 1);
40 
41         //Ending statistics
42         cubs.printStats();
43 
44         nationals.printStats();
45 
46         padres.printStats();
47 
48         Team theWinner = winner(cubs, nationals, padres);
49         //Another way to print the winner:
50         System.out.println("The winner is " + theWinner.getName());
51 
52     }
53 
54     /**
55      * This method takes in three team objects and prints the name of the team
56      * object with the greatest number of wins and returns that team object
57      *
58      * @param a The first team
59      * @param b The second team
60      * @param c The third team
61      * @return The winning team
62      */
63     public static Team winner(Team a, Team b, Team c) {
64         if (a.getWins() > b.getWins() && a.getWins() > c.getWins()) {
65             System.out.println(a.getName());
66             return a;
67         } else if (b.getWins() > a.getWins() && b.getWins() > c.getWins()) {
68             System.out.println(b.getName());
69             return b;
70         } else {
71             System.out.println(c.getName());
72             return c;
73         }
74 
75     }
76 
77 }
78