| // Copyright 2022 The Bazel Authors. All rights reserved. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| // |
| |
| package com.google.devtools.build.lib.util; |
| |
| import com.google.common.base.Objects; |
| import com.google.common.base.Preconditions; |
| import com.google.common.collect.ImmutableSet; |
| import com.google.common.collect.Sets; |
| import java.util.Set; |
| import javax.annotation.Nullable; |
| |
| /** |
| * A set that either contains some elements or is the <i>complete</i> set (semantically contains |
| * every possible value of the element type). |
| */ |
| public final class MaybeCompleteSet<T> { |
| private static final MaybeCompleteSet<Object> COMPLETE = new MaybeCompleteSet<>(null); |
| |
| @Nullable private final ImmutableSet<T> internalSet; |
| |
| private MaybeCompleteSet(@Nullable ImmutableSet<T> nullableSet) { |
| this.internalSet = nullableSet; |
| } |
| |
| public boolean contains(T value) { |
| return internalSet == null || internalSet.contains(value); |
| } |
| |
| public boolean isComplete() { |
| return internalSet == null; |
| } |
| |
| public boolean isEmpty() { |
| return internalSet != null && internalSet.isEmpty(); |
| } |
| |
| public ImmutableSet<T> getElementsIfNotComplete() { |
| Preconditions.checkArgument(internalSet != null); |
| return internalSet; |
| } |
| |
| public static <T> MaybeCompleteSet<T> copyOf(Set<T> nonNullableSet) { |
| return new MaybeCompleteSet<>(ImmutableSet.copyOf(nonNullableSet)); |
| } |
| |
| @SuppressWarnings("unchecked") |
| public static <T> MaybeCompleteSet<T> completeSet() { |
| return (MaybeCompleteSet<T>) COMPLETE; |
| } |
| |
| public static <T> MaybeCompleteSet<T> unionElements(MaybeCompleteSet<T> set1, Set<T> set2) { |
| if (set1.isComplete()) { |
| return completeSet(); |
| } |
| return copyOf(Sets.union(set1.getElementsIfNotComplete(), set2)); |
| } |
| |
| @Override |
| public boolean equals(Object o) { |
| if (this == o) { |
| return true; |
| } |
| if (!(o instanceof MaybeCompleteSet)) { |
| return false; |
| } |
| MaybeCompleteSet<?> that = (MaybeCompleteSet<?>) o; |
| return Objects.equal(internalSet, that.internalSet); |
| } |
| |
| @Override |
| public int hashCode() { |
| return Objects.hashCode("MaybeCompleteSet", internalSet); |
| } |
| } |