1 /** 2 * Copyright (C) 2008 Google Inc. 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.inject; 18 19 import junit.framework.TestCase; 20 21 /** 22 * @author jessewilson (at) google.com (Jesse Wilson) 23 */ 24 public class EagerSingletonTest extends TestCase { 25 26 @Override public void setUp() { 27 A.instanceCount = 0; 28 B.instanceCount = 0; 29 C.instanceCount = 0; 30 } 31 32 public void testJustInTimeEagerSingletons() { 33 Guice.createInjector(Stage.PRODUCTION, new AbstractModule() { 34 protected void configure() { 35 // create a just-in-time binding for A 36 getProvider(A.class); 37 38 // create a just-in-time binding for C 39 requestInjection(new Object() { 40 @Inject void inject(Injector injector) { 41 injector.getInstance(C.class); 42 } 43 }); 44 } 45 }); 46 47 assertEquals(1, A.instanceCount); 48 assertEquals("Singletons discovered when creating singletons should not be built eagerly", 49 0, B.instanceCount); 50 assertEquals(1, C.instanceCount); 51 } 52 53 public void testJustInTimeSingletonsAreNotEager() { 54 Injector injector = Guice.createInjector(Stage.PRODUCTION); 55 injector.getProvider(B.class); 56 assertEquals(0, B.instanceCount); 57 } 58 59 public void testChildEagerSingletons() { 60 Injector parent = Guice.createInjector(Stage.PRODUCTION); 61 parent.createChildInjector(new AbstractModule() { 62 @Override protected void configure() { 63 bind(D.class).to(C.class); 64 } 65 }); 66 67 assertEquals(1, C.instanceCount); 68 } 69 70 @Singleton 71 static class A { 72 static int instanceCount = 0; 73 int instanceId = instanceCount++; 74 75 @Inject A(Injector injector) { 76 injector.getProvider(B.class); 77 } 78 } 79 80 @Singleton 81 static class B { 82 static int instanceCount = 0; 83 int instanceId = instanceCount++; 84 } 85 86 @Singleton 87 static class C implements D { 88 static int instanceCount = 0; 89 int instanceId = instanceCount++; 90 } 91 92 private static interface D {} 93 } 94
