test/com/google/inject/ScopesTest.java

/**
 * Copyright (C) 2006 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.inject;

import junit.framework.TestCase;

import java.io.IOException;

/**
 * @author crazybob@google.com (Bob Lee)
 */
public class ScopesTest extends TestCase {

  @Override protected void setUp() throws Exception {
    AnnotatedSingleton.nextInstanceId = 0;
    BoundAsSingleton.nextInstanceId = 0;
    EagerSingleton.nextInstanceId = 0;
    RealLinkedSingleton.nextInstanceId = 0;
  }

  public void testSingletons() {
    Injector injector = Guice.createInjector(new AbstractModule() {
      protected void configure() {
        bind(BoundAsSingleton.class).in(Scopes.SINGLETON);
        bind(AnnotatedSingleton.class);
        bind(EagerSingleton.class).asEagerSingleton();
        bind(LinkedSingleton.class).to(RealLinkedSingleton.class);
      }
    });

    assertSame(
        injector.getInstance(BoundAsSingleton.class),
        injector.getInstance(BoundAsSingleton.class));

    assertSame(
        injector.getInstance(AnnotatedSingleton.class),
        injector.getInstance(AnnotatedSingleton.class));

    assertSame(
        injector.getInstance(EagerSingleton.class),
        injector.getInstance(EagerSingleton.class));

    assertSame(
        injector.getInstance(LinkedSingleton.class),
        injector.getInstance(LinkedSingleton.class));
  }

  public void testJustInTimeAnnotatedSingleton() {
    Injector injector = Guice.createInjector();

    assertSame(
        injector.getInstance(AnnotatedSingleton.class),
        injector.getInstance(AnnotatedSingleton.class));
  }

  public void testSingletonIsPerInjector() {
    assertNotSame(
        Guice.createInjector().getInstance(AnnotatedSingleton.class),
        Guice.createInjector().getInstance(AnnotatedSingleton.class));
  }

  public void testOverriddingAnnotation() {
    Injector injector = Guice.createInjector(new AbstractModule() {
      protected void configure() {
        bind(AnnotatedSingleton.class).in(Scopes.NO_SCOPE);
      }
    });

    assertNotSame(
        injector.getInstance(AnnotatedSingleton.class),
        injector.getInstance(AnnotatedSingleton.class));
  }

  public void testSingletonsInProductionStage() {
    Guice.createInjector(Stage.PRODUCTION, new AbstractModule() {
      protected void configure() {
        bind(AnnotatedSingleton.class);
        bind(BoundAsSingleton.class).in(Scopes.SINGLETON);
        bind(EagerSingleton.class).asEagerSingleton();
        bind(LinkedSingleton.class).to(RealLinkedSingleton.class);
      }
    });

    assertEquals(1, AnnotatedSingleton.nextInstanceId);
    assertEquals(1, BoundAsSingleton.nextInstanceId);
    assertEquals(1, EagerSingleton.nextInstanceId);
    assertEquals(1, RealLinkedSingleton.nextInstanceId);
  }

  public void testSingletonsInDevelopmentStage() {
    Guice.createInjector(Stage.DEVELOPMENT, new AbstractModule() {
      protected void configure() {
        bind(AnnotatedSingleton.class);
        bind(BoundAsSingleton.class).in(Scopes.SINGLETON);
        bind(EagerSingleton.class).asEagerSingleton();
        bind(LinkedSingleton.class).to(RealLinkedSingleton.class);
      }
    });

    assertEquals(0, AnnotatedSingleton.nextInstanceId);
    assertEquals(0, BoundAsSingleton.nextInstanceId);
    assertEquals(1, EagerSingleton.nextInstanceId);
    assertEquals(0, RealLinkedSingleton.nextInstanceId);
  }

  public void testSingletonScopeIsNotSerializable() throws IOException {
    Asserts.assertNotSerializable(Scopes.SINGLETON);
  }

  public void testNoScopeIsNotSerializable() throws IOException {
    Asserts.assertNotSerializable(Scopes.NO_SCOPE);
  }

  @Singleton
  static class AnnotatedSingleton {
    static int nextInstanceId;
    final int instanceId = nextInstanceId++;
  }

  static class BoundAsSingleton {
    static int nextInstanceId;
    final int instanceId = nextInstanceId++;
  }

  static class EagerSingleton {
    static int nextInstanceId;
    final int instanceId = nextInstanceId++;
  }

  interface LinkedSingleton {}

  @Singleton
  static class RealLinkedSingleton implements LinkedSingleton {
    static int nextInstanceId;
    final int instanceId = nextInstanceId++;
  }
}