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