Java example source code file (InjectorTest.java)

This example Java source code file (InjectorTest.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

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Java - Java tags/keywords

abstractmodule, annotation, bar, bindingannotation, configurationexception, creationexception, inject, injector, object, private, protected, retention, samplesingleton, string, tee, threading, threads

The InjectorTest.java Java example source code

/**
 * 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 static com.google.inject.Asserts.assertContains;
import static com.google.inject.Asserts.assertNotSerializable;
import static java.lang.annotation.RetentionPolicy.RUNTIME;


import junit.framework.TestCase;

import java.io.IOException;
import java.lang.annotation.Retention;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.concurrent.atomic.AtomicReference;

/**
 * @author crazybob@google.com (Bob Lee)
 */

public class InjectorTest extends TestCase {

  @Retention(RUNTIME)
  @BindingAnnotation @interface Other {}

  @Retention(RUNTIME)
  @BindingAnnotation @interface S {}

  @Retention(RUNTIME)
  @BindingAnnotation @interface I {}

  public void testToStringDoesNotInfinitelyRecurse() {
    Injector injector = Guice.createInjector(Stage.TOOL);
    injector.toString();
    injector.getBinding(Injector.class).toString();
  }

  public void testProviderMethods() throws CreationException {
    final SampleSingleton singleton = new SampleSingleton();
    final SampleSingleton other = new SampleSingleton();

    Injector injector = Guice.createInjector(new AbstractModule() {
      protected void configure() {
        bind(SampleSingleton.class).toInstance(singleton);
        bind(SampleSingleton.class)
            .annotatedWith(Other.class)
            .toInstance(other);
      }
    });

    assertSame(singleton,
        injector.getInstance(Key.get(SampleSingleton.class)));
    assertSame(singleton, injector.getInstance(SampleSingleton.class));

    assertSame(other,
        injector.getInstance(Key.get(SampleSingleton.class, Other.class)));
  }

  static class SampleSingleton {}

  public void testInjection() throws CreationException {
    Injector injector = createFooInjector();
    Foo foo = injector.getInstance(Foo.class);

    assertEquals("test", foo.s);
    assertEquals("test", foo.bar.getTee().getS());
    assertSame(foo.bar, foo.copy);
    assertEquals(5, foo.i);
    assertEquals(5, foo.bar.getI());

    // Test circular dependency.
    assertSame(foo.bar, foo.bar.getTee().getBar());
  }

  private Injector createFooInjector() throws CreationException {
    return Guice.createInjector(new AbstractModule() {
      protected void configure() {
        bind(Bar.class).to(BarImpl.class);
        bind(Tee.class).to(TeeImpl.class);
        bindConstant().annotatedWith(S.class).to("test");
        bindConstant().annotatedWith(I.class).to(5);
      }
    });
  }

  public void testGetInstance() throws CreationException {
    Injector injector = createFooInjector();

    Bar bar = injector.getInstance(Key.get(Bar.class));
    assertEquals("test", bar.getTee().getS());
    assertEquals(5, bar.getI());
  }

  public void testIntAndIntegerAreInterchangeable()
      throws CreationException {
    Injector injector = Guice.createInjector(new AbstractModule() {
      protected void configure() {
        bindConstant().annotatedWith(I.class).to(5);
      }
    });

    IntegerWrapper iw = injector.getInstance(IntegerWrapper.class);
    assertEquals(5, (int) iw.i);
  }

  public void testInjectorApiIsNotSerializable() throws IOException {
    Injector injector = Guice.createInjector();
    assertNotSerializable(injector);
    assertNotSerializable(injector.getProvider(String.class));
    assertNotSerializable(injector.getBinding(String.class));
    for (Binding<?> binding : injector.getBindings().values()) {
      assertNotSerializable(binding);
    }
  }

  static class IntegerWrapper {
    @Inject @I Integer i;
  }

  static class Foo {

    @Inject Bar bar;
    @Inject Bar copy;

    @Inject @S String s;

    int i;

    @Inject
    void setI(@I int i) {
      this.i = i;
    }
  }

  interface Bar {

    Tee getTee();
    int getI();
  }

  @Singleton
  static class BarImpl implements Bar {

    @Inject @I int i;

    Tee tee;

    @Inject
    void initialize(Tee tee) {
      this.tee = tee;
    }

    public Tee getTee() {
      return tee;
    }

    public int getI() {
      return i;
    }
  }

  interface Tee {

    String getS();
    Bar getBar();
  }

  static class TeeImpl implements Tee {

    final String s;
    @Inject Bar bar;

    @Inject
    TeeImpl(@S String s) {
      this.s = s;
    }

    public String getS() {
      return s;
    }

    public Bar getBar() {
      return bar;
    }
  }

  public void testInjectStatics() throws CreationException {
    Guice.createInjector(new AbstractModule() {
      protected void configure() {
        bindConstant().annotatedWith(S.class).to("test");
        bindConstant().annotatedWith(I.class).to(5);
        requestStaticInjection(Static.class);
      }
    });

    assertEquals("test", Static.s);
    assertEquals(5, Static.i);
  }

  public void testInjectStaticInterface() {
    try {
      Guice.createInjector(new AbstractModule() {
        protected void configure() {
          requestStaticInjection(Interface.class);
        }
      });
      fail();
    } catch(CreationException ce) {
      assertEquals(1, ce.getErrorMessages().size());
      Asserts.assertContains(
          ce.getMessage(),
          "1) " + Interface.class.getName()
              + " is an interface, but interfaces have no static injection points.",
          "at " + InjectorTest.class.getName(),
          "configure");
    }
  }

  private static interface Interface {}

  static class Static {

    @Inject @I static int i;

    static String s;

    @Inject static void setS(@S String s) {
      Static.s = s;
    }
  }

  public void testPrivateInjection() throws CreationException {
    Injector injector = Guice.createInjector(new AbstractModule() {
      protected void configure() {
        bind(String.class).toInstance("foo");
        bind(int.class).toInstance(5);
      }
    });

    Private p = injector.getInstance(Private.class);
    assertEquals("foo", p.fromConstructor);
    assertEquals(5, p.fromMethod);
  }

  static class Private {
    String fromConstructor;
    int fromMethod;

    @Inject
    private Private(String fromConstructor) {
      this.fromConstructor = fromConstructor;
    }

    @Inject
    private void setInt(int i) {
      this.fromMethod = i;
    }
  }

  public void testProtectedInjection() throws CreationException {
    Injector injector = Guice.createInjector(new AbstractModule() {
      protected void configure() {
        bind(String.class).toInstance("foo");
        bind(int.class).toInstance(5);
      }
    });

    Protected p = injector.getInstance(Protected.class);
    assertEquals("foo", p.fromConstructor);
    assertEquals(5, p.fromMethod);
  }

  static class Protected {
    String fromConstructor;
    int fromMethod;

    @Inject
    protected Protected(String fromConstructor) {
      this.fromConstructor = fromConstructor;
    }

    @Inject
    protected void setInt(int i) {
      this.fromMethod = i;
    }
  }

  public void testInstanceInjectionHappensAfterFactoriesAreSetUp() {
    Guice.createInjector(new AbstractModule() {
      protected void configure() {
        bind(Object.class).toInstance(new Object() {
          @Inject Runnable r;
        });

        bind(Runnable.class).to(MyRunnable.class);
      }
    });
  }

  public void testSubtypeNotProvided() {
    try {
      Guice.createInjector().getInstance(Money.class);
      fail();
    } catch (ProvisionException expected) {
      assertContains(expected.getMessage(),
          Tree.class.getName() + " doesn't provide instances of " + Money.class.getName(),
          "while locating ", Tree.class.getName(),
          "while locating ", Money.class.getName());
    }
  }

  public void testNotASubtype() {
    try {
      Guice.createInjector().getInstance(PineTree.class);
      fail();
    } catch (ConfigurationException expected) {
      assertContains(expected.getMessage(),
          Tree.class.getName() + " doesn't extend " + PineTree.class.getName(),
          "while locating ", PineTree.class.getName());
    }
  }

  public void testRecursiveImplementationType() {
    try {
      Guice.createInjector().getInstance(SeaHorse.class);
      fail();
    } catch (ConfigurationException expected) {
      assertContains(expected.getMessage(),
          "@ImplementedBy points to the same class it annotates.",
          "while locating ", SeaHorse.class.getName());
    }
  }

  public void testRecursiveProviderType() {
    try {
      Guice.createInjector().getInstance(Chicken.class);
      fail();
    } catch (ConfigurationException expected) {
      assertContains(expected.getMessage(),
          "@ProvidedBy points to the same class it annotates",
          "while locating ", Chicken.class.getName());
    }
  }

  static class MyRunnable implements Runnable {
   public void run() {}
  }

  @ProvidedBy(Tree.class)
  static class Money {}

  static class Tree implements Provider<Object> {
    public Object get() {
      return "Money doesn't grow on trees";
    }
  }

  @ImplementedBy(Tree.class)
  static class PineTree extends Tree {}

  @ImplementedBy(SeaHorse.class)
  static class SeaHorse {}

  @ProvidedBy(Chicken.class)
  static class Chicken implements Provider<Chicken> {
    public Chicken get() {
      return this;
    }
  }

  public void testJitBindingFromAnotherThreadDuringInjection() {
    final ExecutorService executorService = Executors.newSingleThreadExecutor();
    final AtomicReference<JustInTime> got = new AtomicReference();

    Guice.createInjector(new AbstractModule() {
      protected void configure() {
        requestInjection(new Object() {
          @Inject void initialize(final Injector injector)
              throws ExecutionException, InterruptedException {
            Future<JustInTime> future = executorService.submit(new Callable() {
              public JustInTime call() throws Exception {
                return injector.getInstance(JustInTime.class);
              }
            });
            got.set(future.get());
          }
        });
      }
    });

    assertNotNull(got.get());
  }

  static class JustInTime {}
}