public/subjects/java/piscine/StreamMap

StreamMap

Instructions

Create a file StreamMap.java.

Create a function sumOfStringLength which returns the sum of the length of the strings in the stream.
Create a function upperCaseAllString which returns the list of all the strings in upper case.
Create a function uniqIntValuesGreaterThan42 which keeps only doubles greater than 42, transforms the doubles to integers and returns them as a set.

Expected Functions

public class StreamMap {
    public static Integer sumOfStringLength(Stream<String> s) {
        // your code here
    }

    public static List<String> upperCaseAllString(Stream<String> s) {
        // your code here
    }
    
    public static Set<Integer> uniqIntValuesGreaterThan42(Stream<Double> s) {
        // your code here
    }
}

Usage

Here is a possible ExerciseRunner.java to test your function :

import java.io.IOException;
import java.util.stream.Stream;

public class ExerciseRunner {
    public static void main(String[] args) throws IOException {
        System.out.println(StreamMap.sumOfStringLength(Stream.of("Bonjour", "le", "monde !")));
        System.out.println(StreamMap.upperCaseAllString(Stream.of("IL", "Fait", "beaU !!")));
        System.out.println(StreamMap.uniqIntValuesGreaterThan42(Stream.of(23.439, 42.34, 39194.4)));
    }
}

and its output :

$ javac *.java -d build
$ java -cp build ExerciseRunner 
16
[IL, FAIT, BEAU !!]
[42, 39194]
$ 

Notions

Stream