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      1 /*
      2  * Copyright (C) 2008 The Guava Authors
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  * http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.google.common.collect.testing.features;
     18 
     19 import com.google.common.collect.testing.Helpers;
     20 
     21 import java.lang.annotation.Inherited;
     22 import java.lang.annotation.Retention;
     23 import java.lang.annotation.RetentionPolicy;
     24 import java.util.Map;
     25 import java.util.Set;
     26 
     27 /**
     28  * Optional features of classes derived from {@code Map}.
     29  *
     30  * <p>This class is GWT compatible.
     31  *
     32  * @author George van den Driessche
     33  */
     34 // Enum values use constructors with generic varargs.
     35 @SuppressWarnings("unchecked")
     36 public enum MapFeature implements Feature<Map> {
     37   /**
     38    * The map does not throw {@code NullPointerException} on calls such as
     39    * {@code containsKey(null)}, {@code get(null)}, or {@code remove(null)}.
     40    */
     41   ALLOWS_NULL_QUERIES,
     42   ALLOWS_NULL_KEYS (ALLOWS_NULL_QUERIES),
     43   ALLOWS_NULL_VALUES,
     44   RESTRICTS_KEYS,
     45   RESTRICTS_VALUES,
     46   SUPPORTS_PUT,
     47   SUPPORTS_PUT_ALL,
     48   SUPPORTS_REMOVE,
     49   SUPPORTS_CLEAR,
     50   /**
     51    * Indicates that the constructor or factory method of a map, usually an
     52    * immutable map, throws an {@link IllegalArgumentException} when presented
     53    * with duplicate keys instead of discarding all but one.
     54    */
     55   REJECTS_DUPLICATES_AT_CREATION,
     56 
     57   GENERAL_PURPOSE(
     58       SUPPORTS_PUT,
     59       SUPPORTS_PUT_ALL,
     60       SUPPORTS_REMOVE,
     61       SUPPORTS_CLEAR
     62   ),
     63 
     64   /** Features supported by maps where only removal is allowed. */
     65   REMOVE_OPERATIONS(
     66       SUPPORTS_REMOVE,
     67       SUPPORTS_CLEAR
     68     );
     69 
     70   private final Set<Feature<? super Map>> implied;
     71 
     72   MapFeature(Feature<? super Map> ... implied) {
     73     this.implied = Helpers.copyToSet(implied);
     74   }
     75 
     76   @Override
     77   public Set<Feature<? super Map>> getImpliedFeatures() {
     78     return implied;
     79   }
     80 
     81   @Retention(RetentionPolicy.RUNTIME)
     82   @Inherited
     83   @TesterAnnotation
     84   public @interface Require {
     85     public abstract MapFeature[] value() default {};
     86     public abstract MapFeature[] absent() default {};
     87   }
     88 }
     89