Przykłady do wpisu o nowej składni switch w Javie 13

PatternMatching.java

String formatted =
    switch (obj) {
        case Integer i -> String.format("int %d", i); 
        case Byte b    -> String.format("byte %d", b); 
        case Long l    -> String.format("long %d", l); 
        case Double d  -> String.format("double %f", d); 
        case String s  -> String.format("String %s, s);
        default        -> String.format("Object %s", obj);
    };

SwitchExpressions.java

public class SwitchExpressions {
    public static void main(String[] args) {
        DaysOfWeek day = SUNDAY;

        System.out.println("Is it a weekend?");

        // #1 old way
        switch(day) {
            case SUNDAY:
            case SATURDAY:
                System.out.println("Yes!");
                break;
            case FRIDAY:
                System.out.println("Almost!");
                break;
            case MONDAY:
            case TUESDAY:
                System.out.println("No");
            default:
                System.out.println(", but it is closer and closer");
        }

        // #2 new way
        switch (day) {
            case SUNDAY, SATURDAY -> System.out.println("Yes!");
            case FRIDAY -> System.out.println("Almost!");
            case MONDAY, TUESDAY ->  System.out.println("No");
            default -> System.out.println("No, but it is closer and closer");
        }
    }
}

SwitchExpressionsFive.java

public class SwitchExpressionsFive {
    public static void main(String[] args) {
        DaysOfWeek day = SUNDAY;

        System.out.println("Is it a weekend?");

        System.out.println(switch (day) {
            case SUNDAY, SATURDAY -> "Yes!";
            case FRIDAY -> "Almost!";
            case MONDAY, TUESDAY -> "No";
            default -> "No, but it is closer and closer";
        });
    }
}

SwitchExpressionsFour.java

public class SwitchExpressionsFour {
    public static void main(String[] args) {
        DaysOfWeek day = SUNDAY;

        System.out.println("Is it a weekend?");

        String isWeekend = switch(day) {
            case SUNDAY:
            case SATURDAY:
                yield "Yes!";
            case FRIDAY:
                yield "Almost!";
            case MONDAY:
                System.out.println("Yw, it's start of the week");
            case TUESDAY:
                yield "No";
            default:
                yield "No, but it is closer and closer";
        };

        System.out.println(isWeekend);
    }
}

SwitchExpressionsThree.java

public class SwitchExpressionsThree {
    public static void main(String[] args) {
        DaysOfWeek day = SUNDAY;

        System.out.println("Is it a weekend?");

        String isNewWeekend = switch (day) {
            case SUNDAY, SATURDAY -> "Yes!";
            case FRIDAY -> "Almost!";
            case MONDAY, TUESDAY ->  "No";
            default -> {
                var x = 10 + 13;
                // do something
                yield "No, but it is closer and closer";
            }
        };

        System.out.println(isNewWeekend);
    }
}

SwitchExpressionsTwo.java

public class SwitchExpressionsTwo {
    public static void main(String[] args) {
        DaysOfWeek day = SUNDAY;

        System.out.println("Is it a weekend?");

        // #1 old way
        String isWeekend;
        switch(day) {
            case SUNDAY:
            case SATURDAY:
                isWeekend = "Yes!";
                break;
            case FRIDAY:
                isWeekend = "Almost!";
                break;
            case MONDAY:
            case TUESDAY:
                isWeekend = "No";
                break;
            default:
                isWeekend = "No, but it is closer and closer";
        }
        System.out.println(isWeekend);

        // #2 new way
        String isNewWeekend = switch (day) {
            case SUNDAY, SATURDAY -> "Yes!";
            case FRIDAY -> "Almost!";
            case MONDAY, TUESDAY ->  "No";
            default -> "No, but it is closer and closer";
        };

        System.out.println(isNewWeekend);
    }
}