1 /* 2 * Copyright (C) 2007 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; 18 19 import com.google.common.base.Function; 20 import com.google.common.testing.GcFinalization; 21 import com.google.common.testing.NullPointerTester; 22 23 import junit.framework.TestCase; 24 25 import java.lang.ref.WeakReference; 26 27 /** 28 * Unit test for {@link Interners}. 29 * 30 * @author Kevin Bourrillion 31 */ 32 public class InternersTest extends TestCase { 33 34 public void testStrong_simplistic() { 35 String canonical = "a"; 36 String not = new String("a"); 37 38 Interner<String> pool = Interners.newStrongInterner(); 39 assertSame(canonical, pool.intern(canonical)); 40 assertSame(canonical, pool.intern(not)); 41 } 42 43 public void testStrong_null() { 44 Interner<String> pool = Interners.newStrongInterner(); 45 try { 46 pool.intern(null); 47 fail(); 48 } catch (NullPointerException ok) {} 49 } 50 51 public void testWeak_simplistic() { 52 String canonical = "a"; 53 String not = new String("a"); 54 55 Interner<String> pool = Interners.newWeakInterner(); 56 assertSame(canonical, pool.intern(canonical)); 57 assertSame(canonical, pool.intern(not)); 58 } 59 60 public void testWeak_null() { 61 Interner<String> pool = Interners.newWeakInterner(); 62 try { 63 pool.intern(null); 64 fail(); 65 } catch (NullPointerException ok) {} 66 } 67 68 public void testWeak_afterGC() throws InterruptedException { 69 Integer canonical = new Integer(5); 70 Integer not = new Integer(5); 71 72 Interner<Integer> pool = Interners.newWeakInterner(); 73 assertSame(canonical, pool.intern(canonical)); 74 75 WeakReference<Integer> signal = new WeakReference<Integer>(canonical); 76 canonical = null; // Hint to the JIT that canonical is unreachable 77 78 GcFinalization.awaitClear(signal); 79 assertSame(not, pool.intern(not)); 80 } 81 82 public void testAsFunction_simplistic() { 83 String canonical = "a"; 84 String not = new String("a"); 85 86 Function<String, String> internerFunction = 87 Interners.asFunction(Interners.<String>newStrongInterner()); 88 89 assertSame(canonical, internerFunction.apply(canonical)); 90 assertSame(canonical, internerFunction.apply(not)); 91 } 92 93 public void testNullPointerExceptions() { 94 new NullPointerTester().testAllPublicStaticMethods(Interners.class); 95 } 96 } 97
