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authorGeoff Liu <cangming.liu@gmail.com>2015-10-29 23:51:14 +0800
committerGeoff Liu <cangming.liu@gmail.com>2015-10-29 23:51:14 +0800
commit1f7d7aa4d68de6615761c2b34307f8cf811f7397 (patch)
tree6f22974ae3bcf2cbba8739521201bc6d1be46b8a /java.html.markdown
parent1f4ffc026ea11776cc0df8327577d0496cf14817 (diff)
parent03ef96b2f11133701a3db64b9133f634a9709e94 (diff)
Merge pull request #1526 from raphaelbn/patch-3
[java/en] Enum Type
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@@ -697,6 +697,64 @@ public abstract class Mammal()
return true;
}
}
+
+
+// Enum Type
+//
+// An enum type is a special data type that enables for a variable to be a set of predefined constants. The // variable must be equal to one of the values that have been predefined for it.
+// Because they are constants, the names of an enum type's fields are in uppercase letters.
+// In the Java programming language, you define an enum type by using the enum keyword. For example, you would
+// specify a days-of-the-week enum type as:
+
+public enum Day {
+ SUNDAY, MONDAY, TUESDAY, WEDNESDAY,
+ THURSDAY, FRIDAY, SATURDAY
+}
+
+// We can use our enum Day like that:
+
+public class EnumTest {
+
+ // Variable Enum
+ Day day;
+
+ public EnumTest(Day day) {
+ this.day = day;
+ }
+
+ public void tellItLikeItIs() {
+ switch (day) {
+ case MONDAY:
+ System.out.println("Mondays are bad.");
+ break;
+
+ case FRIDAY:
+ System.out.println("Fridays are better.");
+ break;
+
+ case SATURDAY:
+ case SUNDAY:
+ System.out.println("Weekends are best.");
+ break;
+
+ default:
+ System.out.println("Midweek days are so-so.");
+ break;
+ }
+ }
+
+ public static void main(String[] args) {
+ EnumTest firstDay = new EnumTest(Day.MONDAY);
+ firstDay.tellItLikeItIs(); // => Mondays are bad.
+ EnumTest thirdDay = new EnumTest(Day.WEDNESDAY);
+ thirdDay.tellItLikeItIs(); // => Midweek days are so-so.
+ }
+}
+
+// Enum types are much more powerful than we show above.
+// The enum body can include methods and other fields.
+// You can se more at https://docs.oracle.com/javase/tutorial/java/javaOO/enum.html
+
```
## Further Reading