CODEWITHSUNDEEP
javamethodsjava-8java-stream
Tiago Silva
Tiago Silva

Reputation: 259

Stream multiple Properties - Java 8 (Basic Example)

I'm using Java 8 and I can get the max and min. Works great but I need to check also the max and min of 10 more properties (e.g., User age, prop1, prop2, prop3, etc...).

How can I do it this instead of replicate the same code 10 times?

IntSummaryStatistics summaryStatistics = data.stream()
            .mapToInt(User::getProp2)
            .summaryStatistics();
    
    int max = summaryStatistics.getMax();
    int min = summaryStatistics.getMin();

And normalize the data between 0 and 5

 data.stream().forEach(d -> {
        d.setNormalized(5 * ((d.getProp2() - min) / (max - min));)
    });

Upvotes: 2

Views: 125

Answers (1)

dreamcrash
dreamcrash

Reputation: 51403

You can try the good old method refactoring in combination with the ToIntFunction interface

public static void normalization(Collection<User> data, ToIntFunction<User> getProp) {
    IntSummaryStatistics summaryStatistics = data.stream()
            .mapToInt(getProp)
            .summaryStatistics();

    int max = summaryStatistics.getMax();
    int min = summaryStatistics.getMin();

    data.forEach(d -> d.setNormalized(5 * ((getProp.applyAsInt(d) - min) / (max - min))));
}

The parameter ToIntFunction<User> getProp is for the "age, prop1, prop2, prop3" part.

To call the method:

normalization(data, User::getProp2);

Upvotes: 2

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