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