guice/core/test/com/google/inject/MethodInterceptionTest.java

/*
 * 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.matcher.Matchers.only;
import static java.lang.annotation.RetentionPolicy.RUNTIME;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertNotNull;
import static org.junit.Assert.assertNull;
import static org.junit.Assert.assertSame;
import static org.junit.Assert.assertTrue;
import static org.junit.Assert.fail;
import static org.junit.Assume.assumeTrue;

import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Iterables;
import com.google.common.collect.Lists;
import com.google.inject.internal.InternalFlags;
import com.google.inject.matcher.AbstractMatcher;
import com.google.inject.matcher.Matchers;
import com.google.inject.name.Names;
import com.google.inject.spi.ConstructorBinding;
import java.lang.annotation.Retention;
import java.lang.reflect.Method;
import java.util.Arrays;
import java.util.List;
import java.util.Queue;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicReference;
import javax.inject.Named;
import org.aopalliance.intercept.MethodInterceptor;
import org.aopalliance.intercept.MethodInvocation;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;

/** @author jessewilson@google.com (Jesse Wilson) */
@RunWith(JUnit4.class)
public class MethodInterceptionTest {

  private AtomicInteger count = new AtomicInteger();

  private final class CountingInterceptor implements MethodInterceptor {
    @Override
    public Object invoke(MethodInvocation methodInvocation) throws Throwable {
      count.incrementAndGet();
      return methodInvocation.proceed();
    }
  }

  private static final class ReturnNullInterceptor implements MethodInterceptor {
    @Override
    public Object invoke(MethodInvocation methodInvocation) throws Throwable {
      return null;
    }
  }

  private static final class NoOpInterceptor implements MethodInterceptor {
    @Override
    public Object invoke(MethodInvocation methodInvocation) throws Throwable {
      return methodInvocation.proceed();
    }
  }

  @Before
  public void checkBytecodeGenIsEnabled() {
    assumeTrue(InternalFlags.isBytecodeGenEnabled());
  }

  @Test
  public void testSharedProxyClasses() {
    Injector injector =
        Guice.createInjector(
            new AbstractModule() {
              @Override
              protected void configure() {
                bindInterceptor(
                    Matchers.any(), Matchers.returns(only(Foo.class)), new ReturnNullInterceptor());
              }
            });

    Injector childOne =
        injector.createChildInjector(
            new AbstractModule() {
              @Override
              protected void configure() {
                bind(Interceptable.class);
              }
            });

    Interceptable nullFoosOne = childOne.getInstance(Interceptable.class);
    assertNotNull(nullFoosOne.bar());
    assertNull(nullFoosOne.foo()); // confirm it's being intercepted

    Injector childTwo =
        injector.createChildInjector(
            new AbstractModule() {
              @Override
              protected void configure() {
                bind(Interceptable.class);
              }
            });

    Interceptable nullFoosTwo = childTwo.getInstance(Interceptable.class);
    assertNull(nullFoosTwo.foo()); // confirm it's being intercepted

    assertSame(
        "Child injectors should share proxy classes, otherwise memory leaks!",
        nullFoosOne.getClass(),
        nullFoosTwo.getClass());

    Injector injector2 =
        Guice.createInjector(
            new AbstractModule() {
              @Override
              protected void configure() {
                bindInterceptor(
                    Matchers.any(), Matchers.returns(only(Foo.class)), new ReturnNullInterceptor());
              }
            });
    Interceptable separateNullFoos = injector2.getInstance(Interceptable.class);
    assertNull(separateNullFoos.foo()); // confirm it's being intercepted
    assertSame(
        "different injectors should share proxy classes, otherwise memory leaks!",
        nullFoosOne.getClass(),
        separateNullFoos.getClass());
  }

  @Test
  public void testGetThis() {
    final AtomicReference<Object> lastTarget = new AtomicReference<>();

    Injector injector =
        Guice.createInjector(
            new AbstractModule() {
              @Override
              protected void configure() {
                bindInterceptor(
                    Matchers.any(),
                    Matchers.any(),
                    new MethodInterceptor() {
                      @Override
                      public Object invoke(MethodInvocation methodInvocation) throws Throwable {
                        lastTarget.set(methodInvocation.getThis());
                        return methodInvocation.proceed();
                      }
                    });
              }
            });

    Interceptable interceptable = injector.getInstance(Interceptable.class);
    interceptable.foo();
    assertSame(interceptable, lastTarget.get());
  }

  @Test
  public void testInterceptingFinalClass() {
    Injector injector =
        Guice.createInjector(
            new AbstractModule() {
              @Override
              protected void configure() {
                bindInterceptor(
                    Matchers.any(),
                    Matchers.any(),
                    new MethodInterceptor() {
                      @Override
                      public Object invoke(MethodInvocation methodInvocation) throws Throwable {
                        return methodInvocation.proceed();
                      }
                    });
              }
            });
    try {
      injector.getInstance(NotInterceptable.class);
      fail();
    } catch (ConfigurationException ce) {
      assertEquals(
          "Unable to method intercept: " + NotInterceptable.class.getName(),
          Iterables.getOnlyElement(ce.getErrorMessages()).getMessage().toString());
      assertEquals(
          "Cannot subclass final class " + NotInterceptable.class.getName(),
          ce.getCause().getMessage());
    }
  }

  @Test
  public void testSpiAccessToInterceptors() throws NoSuchMethodException {
    final MethodInterceptor countingInterceptor = new CountingInterceptor();
    final MethodInterceptor returnNullInterceptor = new ReturnNullInterceptor();
    Injector injector =
        Guice.createInjector(
            new AbstractModule() {
              @Override
              protected void configure() {
                bindInterceptor(
                    Matchers.any(), Matchers.returns(only(Foo.class)), countingInterceptor);
                bindInterceptor(
                    Matchers.any(),
                    Matchers.returns(only(Foo.class).or(only(Bar.class))),
                    returnNullInterceptor);
              }
            });

    ConstructorBinding<?> interceptedBinding =
        (ConstructorBinding<?>) injector.getBinding(Interceptable.class);
    Method barMethod = Interceptable.class.getMethod("bar");
    Method fooMethod = Interceptable.class.getMethod("foo");
    assertEquals(
        ImmutableMap.<Method, List<MethodInterceptor>>of(
            fooMethod, ImmutableList.of(countingInterceptor, returnNullInterceptor),
            barMethod, ImmutableList.of(returnNullInterceptor)),
        interceptedBinding.getMethodInterceptors());

    ConstructorBinding<?> nonInterceptedBinding =
        (ConstructorBinding<?>) injector.getBinding(Foo.class);
    assertEquals(
        ImmutableMap.<Method, List<MethodInterceptor>>of(),
        nonInterceptedBinding.getMethodInterceptors());

    injector.getInstance(Interceptable.class).foo();
    assertEquals("expected counting interceptor to be invoked first", 1, count.get());
  }

  @Test
  public void testInterceptedMethodThrows() throws Exception {
    Injector injector =
        Guice.createInjector(
            new AbstractModule() {
              @Override
              protected void configure() {
                bindInterceptor(Matchers.any(), Matchers.any(), new CountingInterceptor());
                bindInterceptor(Matchers.any(), Matchers.any(), new CountingInterceptor());
              }
            });

    Interceptable interceptable = injector.getInstance(Interceptable.class);
    try {
      interceptable.explode();
      fail();
    } catch (Exception e) {
      // validate all causes.
      for (Throwable t = e; t != null; t = t.getCause()) {
        StackTraceElement[] stackTraceElement = t.getStackTrace();
        assertEquals("explode", stackTraceElement[0].getMethodName());
        assertEquals("invoke", stackTraceElement[1].getMethodName());
        assertEquals("invoke", stackTraceElement[2].getMethodName());
        assertEquals("testInterceptedMethodThrows", stackTraceElement[3].getMethodName());
      }
    }
  }

  @Test
  public void testNotInterceptedMethodsInInterceptedClassDontAddFrames() {
    Injector injector =
        Guice.createInjector(
            new AbstractModule() {
              @Override
              protected void configure() {
                bindInterceptor(
                    Matchers.any(), Matchers.returns(only(Foo.class)), new NoOpInterceptor());
              }
            });

    Interceptable interceptable = injector.getInstance(Interceptable.class);
    assertNull(interceptable.lastElements);
    interceptable.foo();
    boolean proxyFrameFound = false;
    for (int i = 0; i < interceptable.lastElements.length; i++) {
      if (interceptable.lastElements[i].toString().contains("$EnhancerByGuice$")) {
        proxyFrameFound = true;
        break;
      }
    }
    assertTrue(Arrays.toString(interceptable.lastElements), proxyFrameFound);
    proxyFrameFound = false;

    interceptable.bar();
    for (int i = 0; i < interceptable.lastElements.length; i++) {
      if (interceptable.lastElements[i].toString().contains("$EnhancerByGuice$")) {
        proxyFrameFound = true;
        break;
      }
    }
    assertFalse(Arrays.toString(interceptable.lastElements), proxyFrameFound);
  }

  public static class Foo {}

  static class Bar {}

  public static class Interceptable {
    StackTraceElement[] lastElements;

    public Foo foo() {
      lastElements = Thread.currentThread().getStackTrace();
      return new Foo() {};
    }

    public Bar bar() {
      lastElements = Thread.currentThread().getStackTrace();
      return new Bar() {};
    }

    public String explode() throws Exception {
      lastElements = Thread.currentThread().getStackTrace();
      throw new Exception("kaboom!", new RuntimeException("boom!"));
    }
  }

  public static final class NotInterceptable {}

  @Test
  public void testInterceptingNonBridgeWorks() {
    Injector injector =
        Guice.createInjector(
            new AbstractModule() {
              @Override
              protected void configure() {
                bind(Interface.class).to(Impl.class);
                bindInterceptor(
                    Matchers.any(),
                    new AbstractMatcher<Method>() {
                      @Override
                      public boolean matches(Method t) {
                        return !t.isBridge() && t.getDeclaringClass() != Object.class;
                      }
                    },
                    new CountingInterceptor());
              }
            });
    Interface intf = injector.getInstance(Interface.class);
    assertEquals(0, count.get());
    intf.aMethod(null);
    assertEquals(1, count.get());
  }

  static class ErasedType {}

  static class RetType extends ErasedType {}

  abstract static class Superclass<T extends ErasedType> {
    public T aMethod(T t) {
      return null;
    }
  }

  public interface Interface {
    RetType aMethod(RetType obj);
  }

  public static class Impl extends Superclass<RetType> implements Interface {}

  @Test
  public void testInterceptionOrder() {
    final List<String> callList = Lists.newArrayList();
    Injector injector =
        Guice.createInjector(
            new AbstractModule() {
              @Override
              protected void configure() {
                bindInterceptor(
                    Matchers.any(),
                    Matchers.any(),
                    new NamedInterceptor("a", callList),
                    new NamedInterceptor("b", callList),
                    new NamedInterceptor("c", callList));
              }
            });

    Interceptable interceptable = injector.getInstance(Interceptable.class);
    assertEquals(0, callList.size());
    interceptable.foo();
    assertEquals(Arrays.asList("a", "b", "c"), callList);
  }

  private static final class NamedInterceptor implements MethodInterceptor {
    private final String name;
    final List<String> called;

    NamedInterceptor(String name, List<String> callList) {
      this.name = name;
      this.called = callList;
    }

    @Override
    public Object invoke(MethodInvocation methodInvocation) throws Throwable {
      called.add(name);
      return methodInvocation.proceed();
    }
  }

  @Test
  public void testDeDuplicateInterceptors() throws Exception {
    Injector injector =
        Guice.createInjector(
            new AbstractModule() {
              @Override
              protected void configure() {
                CountingInterceptor interceptor = new CountingInterceptor();
                bindInterceptor(Matchers.any(), Matchers.any(), interceptor);
                bindInterceptor(Matchers.any(), Matchers.any(), interceptor);
              }
            });

    Interceptable interceptable = injector.getInstance(Interceptable.class);
    interceptable.foo();
    assertEquals(1, count.get());
  }

  @Test
  public void testCallLater() {
    final Queue<Runnable> queue = Lists.newLinkedList();
    Injector injector =
        Guice.createInjector(
            new AbstractModule() {
              @Override
              protected void configure() {
                bindInterceptor(Matchers.any(), Matchers.any(), new CallLaterInterceptor(queue));
              }
            });

    Interceptable interceptable = injector.getInstance(Interceptable.class);
    interceptable.foo();
    assertNull(interceptable.lastElements);
    assertEquals(1, queue.size());

    queue.remove().run();
    assertNotNull(interceptable.lastElements);
  }

  private static final class CallLaterInterceptor implements MethodInterceptor {
    private final Queue<Runnable> queue;

    public CallLaterInterceptor(Queue<Runnable> queue) {
      this.queue = queue;
    }

    @Override
    public Object invoke(final MethodInvocation methodInvocation) throws Throwable {
      queue.add(
          () -> {
            try {
              methodInvocation.proceed();
            } catch (Throwable t) {
              throw new RuntimeException(t);
            }
          });
      return null;
    }
  }

  @Retention(RUNTIME)
  @interface Grounded {}

  interface Animal {
    default String identifyMyself() {
      return "I am an animal.";
    }
  }

  interface Horse extends Animal {
    @Override
    @Grounded
    default String identifyMyself() {
      return "I am a horse.";
    }
  }

  interface MythicalAnimal extends Animal {}

  interface FlyingHorse extends Horse, MythicalAnimal {
    @Override
    // not Grounded
    default String identifyMyself() {
      return "I am a flying horse.";
    }
  }

  static class HorseImpl implements Horse {}

  // MythicalAnimal shouldn't disturb earlier hierarchy
  public static class Unicorn extends HorseImpl implements MythicalAnimal {}

  // FlyingHorse should be merged into earlier hierarchy
  public static class Pegasus extends HorseImpl implements MythicalAnimal, FlyingHorse {}

  @Test
  public void testDefaultMethodInterception() {
    Injector injector =
        Guice.createInjector(
            new AbstractModule() {
              @Override
              protected void configure() {
                bindInterceptor(
                    Matchers.any(),
                    Matchers.annotatedWith(Grounded.class),
                    new CountingInterceptor());
              }
            });

    assertEquals(0, count.get());
    assertEquals("I am a horse.", injector.getInstance(Unicorn.class).identifyMyself());
    assertEquals(1, count.get()); // unicorn is grounded

    count.set(0); // reset

    assertEquals(0, count.get());
    assertEquals("I am a flying horse.", injector.getInstance(Pegasus.class).identifyMyself());
    assertEquals(0, count.get()); // pegasus is not grounded
  }

  static class BaseSetter {
    String text;

    @Inject
    protected void setText(@Named("text") String text) {
      this.text = text;
    }
  }

  public static class Setter extends BaseSetter {}

  @Test
  public void testSetterInterception() {
    Injector injector =
        Guice.createInjector(
            new AbstractModule() {
              @Override
              protected void configure() {
                bindConstant().annotatedWith(Names.named("text")).to("Hello, world");
                bindInterceptor(
                    Matchers.any(),
                    Matchers.annotatedWith(Inject.class),
                    mi -> {
                      mi.getArguments()[0] = ">>" + mi.getArguments()[0] + "<<";
                      return mi.proceed();
                    });
              }
            });

    Setter setter = injector.getInstance(Setter.class);
    assertEquals(">>Hello, world<<", setter.text);
  }
}