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 com.google.common.annotations.GwtCompatible; 020import com.google.common.collect.testing.Helpers; 021import java.lang.annotation.Inherited; 022import java.lang.annotation.Retention; 023import java.lang.annotation.RetentionPolicy; 024import java.util.Collection; 025import java.util.Collections; 026import java.util.Set; 027 028/** 029 * When describing the features of the collection produced by a given generator (i.e. in a call to 030 * {@link 031 * com.google.common.collect.testing.FeatureSpecificTestSuiteBuilder#withFeatures(Feature...)}), 032 * this annotation specifies each of the different sizes for which a test suite should be built. (In 033 * a typical case, the features should include {@link CollectionSize#ANY}.) These semantics are thus 034 * a little different from those of other Collection-related features such as {@link 035 * CollectionFeature} or {@link SetFeature}. 036 * 037 * <p>However, when {@link CollectionSize.Require} is used to annotate a test it behaves normally 038 * (i.e. it requires the collection instance under test to be a certain size for the test to run). 039 * Note that this means a test should not require more than one CollectionSize, since a particular 040 * collection instance can only be one size at once. 041 * 042 * @author George van den Driessche 043 */ 044// Enum values use constructors with generic varargs. 045@SuppressWarnings("unchecked") 046@GwtCompatible 047public enum CollectionSize implements Feature<Collection>, Comparable<CollectionSize> { 048 /** Test an empty collection. */ 049 ZERO(0), 050 /** Test a one-element collection. */ 051 ONE(1), 052 /** Test a three-element collection. */ 053 SEVERAL(3), 054 /* 055 * TODO: add VERY_LARGE, noting that we currently assume that the fourth 056 * sample element is not in any collection 057 */ 058 059 ANY(ZERO, ONE, SEVERAL); 060 061 private final Set<Feature<? super Collection>> implied; 062 private final Integer numElements; 063 064 CollectionSize(int numElements) { 065 this.implied = Collections.emptySet(); 066 this.numElements = numElements; 067 } 068 069 CollectionSize(Feature<? super Collection>... implied) { 070 // Keep the order here, so that PerCollectionSizeTestSuiteBuilder 071 // gives a predictable order of test suites. 072 this.implied = Helpers.copyToSet(implied); 073 this.numElements = null; 074 } 075 076 @Override 077 public Set<Feature<? super Collection>> getImpliedFeatures() { 078 return implied; 079 } 080 081 public int getNumElements() { 082 if (numElements == null) { 083 throw new IllegalStateException( 084 "A compound CollectionSize doesn't specify a number of elements."); 085 } 086 return numElements; 087 } 088 089 @Retention(RetentionPolicy.RUNTIME) 090 @Inherited 091 @TesterAnnotation 092 public @interface Require { 093 CollectionSize[] value() default {}; 094 095 CollectionSize[] absent() default {}; 096 } 097}