001/*
002 * Copyright (C) 2013 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.google;
018
019import static java.util.Collections.emptySet;
020
021import com.google.common.annotations.GwtCompatible;
022import com.google.common.collect.Multiset;
023import com.google.common.collect.testing.features.Feature;
024import com.google.common.collect.testing.features.TesterAnnotation;
025import java.lang.annotation.Inherited;
026import java.lang.annotation.Retention;
027import java.lang.annotation.RetentionPolicy;
028import java.util.Set;
029
030/**
031 * Optional features of classes derived from {@link Multiset}.
032 *
033 * @author Louis Wasserman
034 */
035@SuppressWarnings("rawtypes") // maybe avoidable if we rework the whole package?
036@GwtCompatible
037public enum MultisetFeature implements Feature<Multiset> {
038  /**
039   * Indicates that elements from {@code Multiset.entrySet()} update to reflect changes in the
040   * backing multiset.
041   */
042  ENTRIES_ARE_VIEWS;
043
044  @Override
045  public Set<Feature<? super Multiset>> getImpliedFeatures() {
046    return emptySet();
047  }
048
049  @Retention(RetentionPolicy.RUNTIME)
050  @Inherited
051  @TesterAnnotation
052  public @interface Require {
053    MultisetFeature[] value() default {};
054
055    MultisetFeature[] absent() default {};
056  }
057}