Record पैटर्न

public class Main {
    record Point(int x, int y) {}

    public static void main(String[] args) {
        Point p = new Point(3, 4);
        System.out.println(p.x() + ", " + p.y());
    }
}

public class Main {
    record Point(int x, int y) {}

    public static void main(String[] args) {
        Object obj = new Point(3, 4);
        if (obj instanceof Point(int x, int y)) {
            System.out.println("Sum: " + (x + y));
        }
    }
}

public class Main {
    record Point(int x, int y) {}

    public static void main(String[] args) {
        Object obj = new Point(10, 20);
        if (obj instanceof Point(int a, int b)) {
            System.out.println("a=" + a + " b=" + b);
        }
    }
}

public class Main {
    record Pair(String key, Integer value) {}

    public static void main(String[] args) {
        Object obj = new Pair("age", 30);
        if (obj instanceof Pair(var key, var value)) {
            System.out.println(key + " = " + value);
        }
    }
}

public class Main {
    record Point(int x, int y) {}

    static String classify(Object obj) {
        return switch (obj) {
            case Point(int x, int y) when x == y -> "on diagonal";
            case Point(int x, int y) -> "at " + x + "," + y;
            default -> "not a point";
        };
    }

    public static void main(String[] args) {
        System.out.println(classify(new Point(5, 5)));
        System.out.println(classify(new Point(1, 2)));
    }
}

public class Main {
    record Temperature(double celsius) {}

    static String alert(Object o) {
        if (o instanceof Temperature(double c) && c > 38.0) {
            return "fever: " + c;
        }
        return "normal";
    }

    public static void main(String[] args) {
        System.out.println(alert(new Temperature(39.5)));
        System.out.println(alert(new Temperature(36.6)));
    }
}

public class Main {
    record Rectangle(int width, int height) {}

    static int area(Object o) {
        if (o instanceof Rectangle(int w, int h)) {
            return w * h;
        }
        return 0;
    }

    public static void main(String[] args) {
        System.out.println(area(new Rectangle(4, 5)));
        System.out.println(area("not a rect"));
    }
}