jkost.github.io/Courses/Mathesis/Intro2ProgrammingWithJava/Week4/4.3-Enums/sandbox/enums.html at master · jkost/jkost.github.io · GitHub

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<!DOCTYPE html>
<html lang="en">
<head>
  <link rel="stylesheet" href="https://javaalmanac.io/almanac.min.css">
</head>
<body>

<div class="content" id="content">

<sandbox version="java17" mainclass="Main" preview="true" v-cloak>
<sandbox-source name="Main.java">
enum Day {
    MON("Monday"), TUE("Tuesday"), WED("Wednesday"), THU("Thursday"), FRI("Friday"), SAT("Saturday"), SUN("Sunday");
    String day;

    Day(String d) {
        day = d;
    }

    String getDay() {
        return day;
    }

    void setDay(String d) {
        this.day = d;
    }

    public static Day fromValue(String value) {
        for (Day type : Day.values()) {
            if (type.getDay().equals(value)) {
                return type;
            }
        }
        throw new IllegalArgumentException("No enum constant for value: " + value);
    }
}

interface Operation {
    long apply(long x, long y);
}

enum BasicOperation implements Operation {
    PLUS {public long apply(long x, long y){return x + y;}},
    MINUS {public long apply(long x, long y){return x - y;}},
    TIMES {public long apply(long x, long y){return x * y;}},
    DIVIDE {public long apply(long x, long y){return x / y;}};
}

public class Main {
    public static void main(String[] args) {
        Day d = Day.MON;
        d.setDay("Δευτέρα");
        System.out.println(d.getDay());
        d = Day.fromValue("Saturday");
        System.out.println(d);

        int a = 4, b = 2;
        Operation op = BasicOperation.PLUS;
        System.out.print(a + " " + op + " " + b + " = " + op.apply(a, b));
    }
}
</sandbox-source>
</sandbox>
</div>
<script src="https://javaalmanac.io/app/sandbox-bundle.js"></script>
<script>new Vue({ el: '#content' })</script>
</body>
</html>