Does Java SE 8 have Pairs or Tuples?

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I am playing around with lazy functional operations in Java SE 8, and I want to map an index i to a pair / tuple (i, value[i]), then filter based on the second value[i] element, and finally output just the indices.

Must I still suffer this: What is the equivalent of the C++ Pair<L,R> in Java? in the bold new era of lambdas and streams?

Update: I presented a rather simplified example, which has a neat solution offered by @dkatzel in one of the answers below. However, it does not generalize. Therefore, let me add a more general example:

package com.example.test;

import java.util.ArrayList;
import java.util.stream.IntStream;

public class Main {

  public static void main(String[] args) {
    boolean [][] directed_acyclic_graph = new boolean[][]{
        {false,  true, false,  true, false,  true},
        {false, false, false,  true, false,  true},
        {false, false, false,  true, false,  true},
        {false, false, false, false, false,  true},
        {false, false, false, false, false,  true},
        {false, false, false, false, false, false}
    };

    System.out.println(
        IntStream.range(0, directed_acyclic_graph.length)
        .parallel()
        .mapToLong(i -> IntStream.range(0, directed_acyclic_graph[i].length)
            .filter(j -> directed_acyclic_graph[j][i])
            .count()
        )
        .filter(n -> n == 0)
        .collect(() -> new ArrayList<Long>(), (c, e) -> c.add(e), (c1, c2) -> c1.addAll(c2))
    );
  }

}

This gives incorrect output of [0, 0, 0] which corresponds to the counts for the three columns that are all false. What I need are the indices of these three columns. The correct output should be [0, 2, 4]. How can I get this result?

10 Answers
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