android/guava/src/com/google/common/collect/EnumMultiset.java
@CanIgnoreReturnValue
  @Override
  public int add(E element, int occurrences) {
    checkIsE(element);
    checkNonnegative(occurrences, "occurrences");
    if (occurrences == 0) {
      return count(element);
    }
    int index = element.ordinal();
    int oldCount = counts[index];
    long newCount = (long) oldCount + occurrences;
    checkArgument(newCount <= Integer.MAX_VALUE, "too many occurrences: %s", newCount);
    counts[index] = (int) newCount;
    if (oldCount == 0) {
      distinctElements++;
    }
    size += occurrences;
    return oldCount;
  }
@CanIgnoreReturnValue
  @Override
  public int add(E element, int occurrences) {
    checkIsE(element);
    checkNonnegative(occurrences, "occurrences");
    if (occurrences == 0) {
      return count(element);
    }
    int index = element.ordinal();
    int oldCount = counts[index];
    long newCount = (long) oldCount + occurrences;
    checkArgument(newCount <= Integer.MAX_VALUE, "too many occurrences: %s", newCount);
    counts[index] = (int) newCount;
    if (oldCount == 0) {
      distinctElements++;
    }
    size += occurrences;
    return oldCount;
  }
Modification Operations