1 /* 2 * Copyright (C) 2009 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; 18 19 import com.google.common.annotations.GwtCompatible; 20 21 import java.util.ArrayList; 22 import java.util.Arrays; 23 import java.util.Collection; 24 import java.util.List; 25 import java.util.Set; 26 27 /** 28 * A simplistic set which implements the bare minimum so that it can be used in 29 * tests without relying on any specific Set implementations. Slow. Explicitly 30 * allows null elements so that they can be used in the testers. 31 * 32 * @author Regina O'Dell 33 */ 34 @GwtCompatible 35 public class MinimalSet<E> extends MinimalCollection<E> implements Set<E> { 36 37 @SuppressWarnings("unchecked") // empty Object[] as E[] of(E... contents)38 public static <E> MinimalSet<E> of(E... contents) { 39 return ofClassAndContents( 40 Object.class, (E[]) new Object[0], Arrays.asList(contents)); 41 } 42 43 @SuppressWarnings("unchecked") // empty Object[] as E[] from(Collection<? extends E> contents)44 public static <E> MinimalSet<E> from(Collection<? extends E> contents) { 45 return ofClassAndContents(Object.class, (E[]) new Object[0], contents); 46 } 47 ofClassAndContents( Class<? super E> type, E[] emptyArrayForContents, Iterable<? extends E> contents)48 public static <E> MinimalSet<E> ofClassAndContents( 49 Class<? super E> type, E[] emptyArrayForContents, 50 Iterable<? extends E> contents) { 51 List<E> setContents = new ArrayList<E>(); 52 for (E e : contents) { 53 if (!setContents.contains(e)) { 54 setContents.add(e); 55 } 56 } 57 return new MinimalSet<E>(type, setContents.toArray(emptyArrayForContents)); 58 } 59 MinimalSet(Class<? super E> type, E... contents)60 private MinimalSet(Class<? super E> type, E... contents) { 61 super(type, true, contents); 62 } 63 64 /* 65 * equals() and hashCode() are more specific in the Set contract. 66 */ 67 equals(Object object)68 @Override public boolean equals(Object object) { 69 if (object instanceof Set) { 70 Set<?> that = (Set<?>) object; 71 return (this.size() == that.size()) && this.containsAll(that); 72 } 73 return false; 74 } 75 hashCode()76 @Override public int hashCode() { 77 int hashCodeSum = 0; 78 for (Object o : this) { 79 hashCodeSum += (o == null) ? 0 : o.hashCode(); 80 } 81 return hashCodeSum; 82 } 83 } 84