简单工厂

 1 package com.disignpattern.simplefactory;
 2 
 3 public abstract class Operation {
 4     private double a;
 5     private double b;
 6     public double getA() {
 7         return a;
 8     }
 9     public void setA(double a) {
10         this.a = a;
11     }
12     public double getB() {
13         return b;
14     }
15     public void setB(double b) {
16         this.b = b;
17     }
18     
19     public abstract double getResult();
20 
21 }
22 
23 
24 
25 public class OperationAdd extends Operation {
26     @Override
27     public double getResult() {
28         return getA() + getB();
29     }
30 }
31 
32 public class OperationDiv extends Operation {
33     @Override
34     public double getResult() {
35         
36         return getA() / getB();
37     }
38 }
39 
40 public class OperationMul extends Operation {
41     @Override
42     public double getResult() {
43         return getA() * getB();
44     }
45 }
46 
47 
48 public class OperationSub extends Operation {
49     @Override
50     public double getResult() {
51         return getA() - getB();
52     }
53 }

 1 public class OperationFactory {
 2     public static Operation getOperation(String s) {
 3         Operation operation = null;
 4         switch (s) {
 5         case "+":
 6             operation = new OperationAdd();
 7             break;
 8         case "-":
 9             operation = new OperationSub();
10             break;
11         case "*":
12             operation = new OperationMul();
13             break;
14         case"/":
15             operation = new OperationDiv();
16             break;
17         }
18             
19         return operation;
20     }
21 }

 1  private static Calendar createCalendar(TimeZone zone,
 2                                            Locale aLocale)
 3     {
 4         CalendarProvider provider =
 5             LocaleProviderAdapter.getAdapter(CalendarProvider.class, aLocale)
 6                                  .getCalendarProvider();
 7         if (provider != null) {
 8             try {
 9                 return provider.getInstance(zone, aLocale);
10             } catch (IllegalArgumentException iae) {
11                 // fall back to the default instantiation
12             }
13         }
14 
15         Calendar cal = null;
16 
17         if (aLocale.hasExtensions()) {
18             String caltype = aLocale.getUnicodeLocaleType("ca");
19             if (caltype != null) {
20                 switch (caltype) {
21                 case "buddhist":
22                 cal = new BuddhistCalendar(zone, aLocale);
23                     break;
24                 case "japanese":
25                     cal = new JapaneseImperialCalendar(zone, aLocale);
26                     break;
27                 case "gregory":
28                     cal = new GregorianCalendar(zone, aLocale);
29                     break;
30                 }
31             }
32         }
33 }