001/*
002 * Copyright (C) 2008 The Guava Authors
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 * http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package com.google.common.collect.testing.features;
018
019import static com.google.common.collect.testing.Helpers.copyToSet;
020import static java.util.Collections.emptySet;
021
022import com.google.common.annotations.GwtCompatible;
023import java.lang.annotation.Inherited;
024import java.lang.annotation.Retention;
025import java.lang.annotation.RetentionPolicy;
026import java.util.Collection;
027import java.util.Set;
028import org.jspecify.annotations.Nullable;
029
030/**
031 * When describing the features of the collection produced by a given generator (i.e. in a call to
032 * {@link
033 * com.google.common.collect.testing.FeatureSpecificTestSuiteBuilder#withFeatures(Feature...)}),
034 * this annotation specifies each of the different sizes for which a test suite should be built. (In
035 * a typical case, the features should include {@link CollectionSize#ANY}.) These semantics are thus
036 * a little different from those of other Collection-related features such as {@link
037 * CollectionFeature} or {@link SetFeature}.
038 *
039 * <p>However, when {@link CollectionSize.Require} is used to annotate a test it behaves normally
040 * (i.e. it requires the collection instance under test to be a certain size for the test to run).
041 * Note that this means a test should not require more than one CollectionSize, since a particular
042 * collection instance can only be one size at once.
043 *
044 * @author George van den Driessche
045 */
046@SuppressWarnings("rawtypes") // maybe avoidable if we rework the whole package?
047@GwtCompatible
048public enum CollectionSize implements Feature<Collection>, Comparable<CollectionSize> {
049  /** Test an empty collection. */
050  ZERO(0),
051  /** Test a one-element collection. */
052  ONE(1),
053  /** Test a three-element collection. */
054  SEVERAL(3),
055  /*
056   * TODO: add VERY_LARGE, noting that we currently assume that the fourth
057   * sample element is not in any collection
058   */
059
060  ANY(ZERO, ONE, SEVERAL);
061
062  private final Set<Feature<? super Collection>> implied;
063  private final @Nullable Integer numElements;
064
065  CollectionSize(int numElements) {
066    this.implied = emptySet();
067    this.numElements = numElements;
068  }
069
070  CollectionSize(Feature<? super Collection>... implied) {
071    // Keep the order here, so that PerCollectionSizeTestSuiteBuilder
072    // gives a predictable order of test suites.
073    this.implied = copyToSet(implied);
074    this.numElements = null;
075  }
076
077  @Override
078  public Set<Feature<? super Collection>> getImpliedFeatures() {
079    return implied;
080  }
081
082  public int getNumElements() {
083    if (numElements == null) {
084      throw new IllegalStateException(
085          "A compound CollectionSize doesn't specify a number of elements.");
086    }
087    return numElements;
088  }
089
090  @Retention(RetentionPolicy.RUNTIME)
091  @Inherited
092  @TesterAnnotation
093  public @interface Require {
094    CollectionSize[] value() default {};
095
096    CollectionSize[] absent() default {};
097  }
098}