Records and pattern matching in Java

Java

A record plus a switch pattern removes most of the ceremony this used to take.

sealed interface Shape permits Circle, Square {}
record Circle(double r) implements Shape {}
record Square(double side) implements Shape {}

double area(Shape s) {
    return switch (s) {
        case Circle c -> Math.PI * c.r() * c.r();
        case Square q -> q.side() * q.side();
    };
}

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Systems java records pattern-matching chris

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