1/* 2 * Copyright (C) 2010 The Android Open Source Project 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 17package libcore.util; 18 19import java.lang.ref.Reference; 20import java.lang.ref.WeakReference; 21import java.util.ArrayList; 22import java.util.Arrays; 23import java.util.Collections; 24import java.util.Iterator; 25import java.util.List; 26import junit.framework.TestCase; 27 28public final class CollectionUtilsTest extends TestCase { 29 30 public void testDereferenceIterable() { 31 List<Reference<String>> refs = new ArrayList<Reference<String>>(); 32 refs.add(newLiteralReference("a")); 33 refs.add(newLiteralReference("b")); 34 refs.add(newLiteralReference("c")); 35 refs.add(newLiteralReference("d")); 36 refs.add(newLiteralReference("e")); 37 38 Iterable<String> strings = CollectionUtils.dereferenceIterable(refs, true); 39 assertEquals(Arrays.<String>asList("a", "b", "c", "d", "e"), toList(strings)); 40 41 refs.get(1).clear(); // b 42 assertEquals(Arrays.<String>asList("a", "c", "d", "e"), toList(strings)); 43 assertEquals(4, refs.size()); 44 45 Iterator<String> i = strings.iterator(); 46 assertEquals("a", i.next()); 47 i.remove(); 48 assertEquals(3, refs.size()); 49 assertEquals("c", i.next()); 50 assertEquals("d", i.next()); 51 assertTrue(i.hasNext()); 52 try { 53 i.remove(); 54 fail("Expected hasNext() to make remove() impossible."); 55 } catch (IllegalStateException expected) { 56 } 57 assertEquals("e", i.next()); 58 i.remove(); 59 assertEquals(2, refs.size()); 60 assertFalse(i.hasNext()); 61 62 refs.get(0).clear(); // c 63 refs.get(1).clear(); // d 64 assertEquals(Arrays.<String>asList(), toList(strings)); 65 } 66 67 private <T> List<T> toList(Iterable<T> iterable) { 68 List<T> result = new ArrayList<T>(); 69 for (T t : iterable) { 70 result.add(t); 71 } 72 return result; 73 } 74 75 public void testRemoveDuplicatesOnEmptyCollection() { 76 List<String> list = new ArrayList<String>(); 77 CollectionUtils.removeDuplicates(list, String.CASE_INSENSITIVE_ORDER); 78 assertTrue(list.isEmpty()); 79 } 80 81 public void testRemoveDuplicatesOnSingletonCollection() { 82 List<String> list = Arrays.asList("A"); 83 CollectionUtils.removeDuplicates(list, String.CASE_INSENSITIVE_ORDER); 84 assertEquals(Collections.singletonList("A"), list); 85 } 86 87 public void testRemoveDuplicates() { 88 List<String> list = new ArrayList<String>(); 89 list.add("A"); 90 list.add("A"); 91 list.add("A"); 92 list.add("B"); 93 list.add("C"); 94 list.add("C"); 95 list.add("C"); 96 CollectionUtils.removeDuplicates(list, String.CASE_INSENSITIVE_ORDER); 97 assertEquals(Arrays.asList("A", "B", "C"), list); 98 } 99 100 /** 101 * A reference that must be manually cleared. 102 */ 103 public Reference<String> newLiteralReference(String s) { 104 return new WeakReference<String>(s); 105 } 106} 107