java_upgrade/src/test/java/streams/StringExercises.java at main · alcmontejo/java_upgrade · GitHub

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package streams;

import org.junit.jupiter.api.Test;

import java.util.Arrays;

import java.util.Comparator;

import java.util.List;

import java.util.function.Function;

public class StringExercises {

private final List<String> strings = Arrays.asList("this", "is", "a",

"list", "of", "strings");

@Test

public void stringLengthSort_InnerClass() { // Java 5, 6, 7

strings.sort(new Comparator<String>() {

@Override

public int compare(String s1, String s2) {

return s1.length() - s2.length();

}

});

System.out.println(strings);

}

@Test

public void stringLengthSort_lambda() {

// Use lambda for the Comparator (reverse sort)

// Use the "sorted" method on Stream

}

private int compareStrings(String s1, String s2) {

return s1.length() - s2.length();

}

@Test // Use a lambda that calls 'compareStrings' directly

public void stringLengthSort_methodCall() {

}

@Test // Use a method ref to 'compareStrings'

public void stringLengthSort_methodRef() {

}

@Test // Use Comparator.comparingInt

public void stringLengthSort_comparingInt() {

}

@Test

public void demoCollectors() {

// Get only strings of even length

// Add them to a LinkedList

// Add the strings to a map of string to length

// Filter out nulls, then print even-length strings

// Function composition

// Combine the two predicates and use the result to print non-null, even-length strings

// f: A -> B, g: B -> C, (g.f)(x) = g(f(x)), A -> C

}

// generated by GitHub Copilot

private <A, B, C> Function<A, C> compose(Function<A, B> f, Function<B, C> g) {

return x -> g.apply(f.apply(x));

}

java_upgrade/src/test/java/streams/StringExercises.java at main · alcmontejo/java_upgrade · GitHub

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