Method ArrowSet

core/src/main/java/org/apache/calcite/util/ArrowSet.java:60–79

(Set<Arrow> arrows)

  private final ImmutableMap<Integer, ImmutableSet<Arrow>> ordinalToArrows;

  public ArrowSet(Set<Arrow> arrows) {
    Set<Arrow> minimalArrows = computeMinimalDependencySet(arrows);
    arrowSet = ImmutableList.copyOf(minimalArrows);
    Map<ImmutableBitSet, ImmutableBitSet> detToDep = new HashMap<>();
    Map<Integer, Set<Arrow>> ordToArrows = new HashMap<>();
    for (Arrow arrow : minimalArrows) {
      ImmutableBitSet determinants = arrow.getDeterminants();
      ImmutableBitSet dependents = arrow.getDependents();
      detToDep.merge(determinants, dependents, ImmutableBitSet::union);
      for (int det : determinants) {
        ordToArrows.computeIfAbsent(det, k -> new HashSet<>()).add(arrow);
      }
    }
    determinantsToDependentsMap = ImmutableMap.copyOf(detToDep);
    ImmutableMap.Builder<Integer, ImmutableSet<Arrow>> builder = ImmutableMap.builder();
    for (Map.Entry<Integer, Set<Arrow>> entry : ordToArrows.entrySet()) {
      builder.put(entry.getKey(), ImmutableSet.copyOf(entry.getValue()));
    }
    ordinalToArrows = builder.build();
  }

  //~ Methods ----------------------------------------------------------------