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Java example source code file (MiniGuiceTest.java)

This example Java source code file (MiniGuiceTest.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

atomicreference, inject, named, object, provider, provides, singleton

The MiniGuiceTest.java Java example source code

/*
 * Copyright (C) 2010 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.mini;

import com.google.inject.Provides;

import junit.framework.TestCase;

import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicReference;

import javax.inject.Inject;
import javax.inject.Named;
import javax.inject.Provider;
import javax.inject.Singleton;

public final class MiniGuiceTest extends TestCase {

  public void testBasicInjection() {
    G g = MiniGuice.inject(G.class, new Object() {
      @Provides E provideE(F f) {
        return new E(f);
      }
      @Provides F provideF() {
        return new F();
      }
    });

    assertNotNull(g.a);
    assertNotNull(g.b);
    assertNotNull(g.c);
    assertNotNull(g.d);
    assertNotNull(g.e);
    assertNotNull(g.e.f);
  }

  static class A {
    @Inject A() {}
  }

  static class B {
    @Inject B() {}
  }

  @Singleton
  static class C {
    @Inject C() {}
  }

  @Singleton
  static class D {
    @Inject D() {}
  }

  static class E {
    F f;
    E(F f) {
      this.f = f;
    }
  }

  static class F {}

  static class G {
    @Inject A a;
    @Inject B b;
    C c;
    D d;
    @Inject E e;
    @Inject G(C c, D d) {
      this.c = c;
      this.d = d;
    }
  }
  
  public void testProviderInjection() {
    H h = MiniGuice.inject(H.class);
    assertNotNull(h.aProvider.get());
    assertNotNull(h.aProvider.get());
    assertNotSame(h.aProvider.get(), h.aProvider.get());
  }

  static class H {
    @Inject Provider<A> aProvider;
    @Inject H() {}
  }
  
  public void testSingletons() {
    J j = MiniGuice.inject(J.class, new Object() {
      @Provides @Singleton F provideK() {
        return new F();
      }
    });
    assertSame(j.fProvider.get(), j.fProvider.get());
    assertSame(j.iProvider.get(), j.iProvider.get());
  }

  @Singleton
  static class I {
    @Inject I() {}
  }

  static class J {
    @Inject Provider<F> fProvider;
    @Inject Provider<I> iProvider;
    @Inject J() {}
  }

  public void testBindingAnnotations() {
    final A one = new A();
    final A two = new A();

    K k = MiniGuice.inject(K.class, new Object() {
      @Provides @Named("one") A getOne() {
        return one;
      }
      @Provides @Named("two") A getTwo() {
        return two;
      }
    });

    assertNotNull(k.a);
    assertSame(one, k.aOne);
    assertSame(two, k.aTwo);
  }

  public static class K {
    @Inject A a;
    @Inject @Named("one") A aOne;
    @Inject @Named("two") A aTwo;
  }
  
  public void testSingletonBindingAnnotationAndProvider() {
    final AtomicReference<A> a1 = new AtomicReference();
    final AtomicReference<A> a2 = new AtomicReference();

    L l = MiniGuice.inject(L.class, new Object() {
      @Provides @Singleton @Named("one") F provideF(Provider<A> aProvider) {
        a1.set(aProvider.get());
        a2.set(aProvider.get());
        return new F();
      }
    });

    assertNotNull(a1.get());
    assertNotNull(a2.get());
    assertNotSame(a1.get(), a2.get());
    assertSame(l, l.lProvider.get());
  }

  @Singleton
  public static class L {
    @Inject @Named("one") F f;
    @Inject Provider<L> lProvider;
  }

  public void testSingletonInGraph() {
    M m = MiniGuice.inject(M.class, new Object() {
      @Provides @Singleton F provideF() {
        return new F();
      }
    });

    assertSame(m.f1, m.f2);
    assertSame(m.f1, m.n1.f1);
    assertSame(m.f1, m.n1.f2);
    assertSame(m.f1, m.n2.f1);
    assertSame(m.f1, m.n2.f2);
    assertSame(m.f1, m.n1.fProvider.get());
    assertSame(m.f1, m.n2.fProvider.get());
  }

  public static class M {
    @Inject N n1;
    @Inject N n2;
    @Inject F f1;
    @Inject F f2;
  }

  public static class N {
    @Inject F f1;
    @Inject F f2;
    @Inject Provider<F> fProvider;
  }

  public void testNoJitBindingsForAnnotations() {
    try {
      MiniGuice.inject(O.class);
      fail();
    } catch (IllegalArgumentException expected) {
    }
  }

  public static class O {
    @Inject @Named("a") A a;
  }

  public void testSubclasses() {
    Q q = MiniGuice.inject(Q.class, new Object() {
      @Provides F provideF() {
        return new F();
      }
    });

    assertNotNull(q.f);
  }
  
  public static class P {
    @Inject F f;
  }

  public static class Q extends P {
    @Inject Q() {}
  }
  
  public void testSingletonsAreEager() {
    final AtomicBoolean sInjected = new AtomicBoolean();

    R.injected = false;
    MiniGuice.inject(A.class, new Object() {
      @Provides F provideF(R r) {
        return new F();
      }

      @Provides @Singleton S provideS() {
        sInjected.set(true);
        return new S();
      }
    });

    assertTrue(R.injected);
    assertTrue(sInjected.get());
  }

  @Singleton
  static class R {
    static boolean injected = false;
    @Inject R() {
      injected = true;
    }
  }

  static class S {}
}


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