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Java example source code file (OptionalBindingTest.java)

This example Java source code file (OptionalBindingTest.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.

Learn more about this Java project at its project page.

Java - Java tags/keywords

abstractmodule, configurationexception, hasoptionalconstructor, hasoptionalinjections, hasoptionalinjectionsprovider, indirect, inject, injectedconstructorannotations, optionalbindingtest, provider, suppresswarnings

The OptionalBindingTest.java Java example source code

/**
 * Copyright (C) 2008 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 com.google.inject.name.Named;
import com.google.inject.name.Names;

import junit.framework.TestCase;

/**
 * This test verifies the ways things are injected (ie. getInstance(),
 * injectMembers(), bind to instance, and bind to provider instance) for all
 * states of optional bindings (fields, methods, multiple-argument methods,
 * provider fields, provider methods, constructors).
 *
 * @author jessewilson@google.com (Jesse Wilson)
 */
public class OptionalBindingTest extends TestCase {

  private static final A injectA = new A() {};
  private static final B injectB = new B() {};
  private static final C injectC = new C() {};
  private static final D injectD = new D() {};
  private static final E injectE = new E() {};
  private static final F injectF = new F() {};
  private static final G injectG = new G() {};

  private Module everythingModule = new AbstractModule() {
    protected void configure() {
      bind(A.class).toInstance(injectA);
      bind(B.class).toInstance(injectB);
      bind(C.class).toInstance(injectC);
      bind(D.class).toInstance(injectD);
      bind(E.class).annotatedWith(Names.named("e")).toInstance(injectE);
      bind(F.class).toInstance(injectF);
      bind(G.class).toInstance(injectG);
    }
  };

  private Module partialModule = new AbstractModule() {
    protected void configure() {
      bind(C.class).toInstance(new C() {});
    }
  };

  private Module toInstanceModule = new AbstractModule() {
    protected void configure() {
      bind(HasOptionalInjections.class)
          .toInstance(new HasOptionalInjections());
    }
  };

  private Module toProviderInstanceModule = new AbstractModule() {
    protected void configure() {
      bind(HasOptionalInjections.class)
          .toProvider(new HasOptionalInjectionsProvider());
    }
  };

  private Module toProviderModule = new AbstractModule() {
    protected void configure() {
      bind(HasOptionalInjections.class)
          .toProvider(HasOptionalInjectionsProvider.class);
    }
  };

  public void testEverythingInjectorGetInstance() {
    Guice.createInjector(everythingModule)
        .getInstance(HasOptionalInjections.class)
        .assertEverythingInjected();
  }

  public void testPartialInjectorGetInstance() {
    Guice.createInjector(partialModule)
        .getInstance(HasOptionalInjections.class)
        .assertNothingInjected();
  }

  public void testNothingInjectorGetInstance() {
    Guice.createInjector()
        .getInstance(HasOptionalInjections.class)
        .assertNothingInjected();
  }

  public void testEverythingInjectorInjectMembers() {
    HasOptionalInjections instance = new HasOptionalInjections();
    Guice.createInjector(everythingModule).injectMembers(instance);
    instance.assertEverythingInjected();
  }

  public void testPartialInjectorInjectMembers() {
    HasOptionalInjections instance = new HasOptionalInjections();
    Guice.createInjector(partialModule).injectMembers(instance);
    instance.assertNothingInjected();
  }

  public void testNothingInjectorInjectMembers() {
    HasOptionalInjections instance = new HasOptionalInjections();
    Guice.createInjector().injectMembers(instance);
    instance.assertNothingInjected();
  }

  public void testEverythingInjectorToInstance() {
    Guice.createInjector(everythingModule, toInstanceModule)
        .getInstance(HasOptionalInjections.class)
        .assertEverythingInjected();
  }

  public void testPartialInjectorToInstance() {
    Guice.createInjector(partialModule, toInstanceModule)
        .getInstance(HasOptionalInjections.class)
        .assertNothingInjected();
  }

  public void testNothingInjectorToInstance() {
    Guice.createInjector(toInstanceModule)
        .getInstance(HasOptionalInjections.class)
        .assertNothingInjected();
  }
  
  public void testEverythingInjectorToProviderInstance() {
    Guice.createInjector(everythingModule, toProviderInstanceModule)
        .getInstance(HasOptionalInjections.class)
        .assertEverythingInjected();
  }

  public void testPartialInjectorToProviderInstance() {
    Guice.createInjector(partialModule, toProviderInstanceModule)
        .getInstance(HasOptionalInjections.class)
        .assertNothingInjected();
  }

  public void testNothingInjectorToProviderInstance() {
    Guice.createInjector(toProviderInstanceModule)
        .getInstance(HasOptionalInjections.class)
        .assertNothingInjected();
  }

  public void testEverythingInjectorToProvider() {
    Guice.createInjector(everythingModule, toProviderModule)
        .getInstance(HasOptionalInjections.class)
        .assertEverythingInjected();
  }

  public void testPartialInjectorToProvider() {
    Guice.createInjector(partialModule, toProviderModule)
        .getInstance(HasOptionalInjections.class)
        .assertNothingInjected();
  }

  public void testNothingInjectorToProvider() {
    Guice.createInjector(toProviderModule)
        .getInstance(HasOptionalInjections.class)
        .assertNothingInjected();
  }

  static class HasOptionalInjections {
    A originalA = new A() {};
    @Inject(optional=true) A a = originalA; // field injection
    B b; // method injection with one argument
    C c; // method injection with two arguments
    D d; // method injection with two arguments
    E e; // annotated injection
    @Inject(optional=true) Provider<F> fProvider; // provider
    Provider<G> gProvider; // method injection of provider
    boolean invoked0, invoked1, invoked2, invokedAnnotated, invokeProvider;

    @Inject(optional=true) void methodInjectZeroArguments() {
      invoked0 = true;
    }

    @Inject(optional=true) void methodInjectOneArgument(B b) {
      this.b = b;
      invoked1 = true;
    }

    @Inject(optional=true) void methodInjectTwoArguments(C c, D d) {
      this.c = c;
      this.d = d;
      invoked2 = true;
    }

    @Inject(optional=true) void methodInjectAnnotated(@Named("e") E e) {
      this.e = e;
      invokedAnnotated = true;
    }

    @Inject(optional=true) void methodInjectProvider(Provider<G> gProvider) {
      this.gProvider = gProvider;
      invokeProvider = true;
    }

    void assertNothingInjected() {
      assertSame(originalA, a);
      assertNull(b);
      assertNull(c);
      assertNull(d);
      assertNull(e);
      assertNull(fProvider);
      assertNull(gProvider);
      assertTrue(invoked0);
      assertFalse(invoked1);
      assertFalse(invoked2);
      assertFalse(invokedAnnotated);
    }

    public void assertEverythingInjected() {
      assertNotSame(injectA, originalA);
      assertSame(injectA, a);
      assertSame(injectB, b);
      assertSame(injectC, c);
      assertSame(injectD, d);
      assertSame(injectE, e);
      assertSame(injectF, fProvider.get());
      assertSame(injectG, gProvider.get());
      assertTrue(invoked0);
      assertTrue(invoked1);
      assertTrue(invoked2);
      assertTrue(invokedAnnotated);
    }
  }

  static class HasOptionalInjectionsProvider
      extends HasOptionalInjections implements Provider<HasOptionalInjections> {
    public HasOptionalInjections get() {
      return this;
    }
  }

  public void testOptionalConstructorBlowsUp() {
    try {
      Guice.createInjector().getInstance(HasOptionalConstructor.class);
      fail();
    } catch (ConfigurationException expected) {
      assertContains(expected.getMessage(), "OptionalBindingTest$HasOptionalConstructor.<init>() "
          + "is annotated @Inject(optional=true), but constructors cannot be optional.");
    }
  }

  static class HasOptionalConstructor {
    // Suppress compiler errors by the error-prone checker InjectedConstructorAnnotations,
    // which catches optional injected constructors.
    @SuppressWarnings("InjectedConstructorAnnotations")
    @Inject(optional=true)
    HasOptionalConstructor() {}
  }

  @Inject(optional=true) static A staticInjectA;

  public void testStaticInjection() {
    staticInjectA = injectA;
    Guice.createInjector(new AbstractModule() {
      protected void configure() {
        requestStaticInjection(OptionalBindingTest.class);
      }
    });
    assertSame(staticInjectA, injectA);
  }

  /**
   * Test for bug 107, where we weren't doing optional injection properly for
   * indirect injections.
   */
  public void testIndirectOptionalInjection() {
    Indirect indirect = Guice.createInjector().getInstance(Indirect.class);
    assertNotNull(indirect.hasOptionalInjections);
    indirect.hasOptionalInjections.assertNothingInjected();
  }

  static class Indirect {
    @Inject HasOptionalInjections hasOptionalInjections;
  }

  interface A {}
  interface B {}
  interface C {}
  interface D {}
  interface E {}
  interface F {}
  interface G {}
}

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