001/* 002 * Copyright (C) 2009 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; 018 019import com.google.common.annotations.GwtCompatible; 020import java.util.ArrayList; 021import java.util.Arrays; 022import java.util.Collection; 023import java.util.List; 024import java.util.Set; 025 026/** 027 * A simplistic set which implements the bare minimum so that it can be used in tests without 028 * relying on any specific Set implementations. Slow. Explicitly allows null elements so that they 029 * can be used in the testers. 030 * 031 * @author Regina O'Dell 032 */ 033@GwtCompatible 034public class MinimalSet<E> extends MinimalCollection<E> implements Set<E> { 035 036 @SuppressWarnings("unchecked") // empty Object[] as E[] 037 public static <E> MinimalSet<E> of(E... contents) { 038 return ofClassAndContents(Object.class, (E[]) new Object[0], Arrays.asList(contents)); 039 } 040 041 @SuppressWarnings("unchecked") // empty Object[] as E[] 042 public static <E> MinimalSet<E> from(Collection<? extends E> contents) { 043 return ofClassAndContents(Object.class, (E[]) new Object[0], contents); 044 } 045 046 public static <E> MinimalSet<E> ofClassAndContents( 047 Class<? super E> type, E[] emptyArrayForContents, Iterable<? extends E> contents) { 048 List<E> setContents = new ArrayList<E>(); 049 for (E e : contents) { 050 if (!setContents.contains(e)) { 051 setContents.add(e); 052 } 053 } 054 return new MinimalSet<E>(type, setContents.toArray(emptyArrayForContents)); 055 } 056 057 private MinimalSet(Class<? super E> type, E... contents) { 058 super(type, true, contents); 059 } 060 061 /* 062 * equals() and hashCode() are more specific in the Set contract. 063 */ 064 065 @Override 066 public boolean equals(Object object) { 067 if (object instanceof Set) { 068 Set<?> that = (Set<?>) object; 069 return (this.size() == that.size()) && this.containsAll(that); 070 } 071 return false; 072 } 073 074 @Override 075 public int hashCode() { 076 int hashCodeSum = 0; 077 for (Object o : this) { 078 hashCodeSum += (o == null) ? 0 : o.hashCode(); 079 } 080 return hashCodeSum; 081 } 082}