CODEWITHSUNDEEP
java
Parazit-nsk
Parazit-nsk

Reputation: 21

How to combine similar methods?

I have quite the same methods, but for different fields of class. How can I make a method that will do both of these things, depending on parameters.

Thanks in advance.

    private int getLengthOfLongestName(List<Driver> drivers) {
        return drivers.stream()
                .map(t -> t.getName())
                .max(Comparator.comparingInt(String::length))
                .map(String::length)
                .orElse(0);
    }

    private int getLengthOfLongestTeam(List<Driver> drivers) {
        return drivers.stream()
                .map(t -> t.getTeamName())
                .max(Comparator.comparingInt(String::length))
                .map(String::length)
                .orElse(0);
    }

Upvotes: 1

Views: 119

Answers (2)

Ryuzaki L
Ryuzaki L

Reputation: 40048

You can pass Function as parameter to getLongestValue and just use max to get maximum value

private int getLongestValue(List<Driver> drivers, Function<Driver, String> func) {
    return drivers.stream()
            .map(func)
            .mapToInt(String::length)
            .max()
            .orElse(0);
}

So you can use it for mapping different values

getLongestValue(list, Driver::getName)
getLongestValue(list, Driver::getTeamName)

Upvotes: 3

kaya3
kaya3

Reputation: 51034

Take a Function as a parameter:

    private int getLengthOfLongest(List<Driver> drivers, Function<Driver, String> func) {
        return drivers.stream()
                .map(func)
                .mapToInt(String::length)
                .max()
                .orElse(0);
    }

Then you can call it like getLengthOfLongest(driverList, Driver::getName), or use Driver::getTeamName for the other version.

Note that it's a bit simpler to mapToInt to the string lengths before taking the max, as this avoids taking the string length twice, and then you have an IntStream so you don't need to provide an explicit comparator.

I would also recommend using a method reference like Driver::getName instead of a lambda like t -> t.getName() as this makes it more explicit what type of thing you are getting the name of.

Upvotes: 11

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