import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;

/**
 * Captures the actual type of {@code T}.
 *
 * @author Ben Yu
 */
@ElementTypesAreNonnullByDefault
abstract class TypeCapture<T> {

  /** Returns the captured type. */
  final Type capture() {
    Type superclass = getClass().getGenericSuperclass();
    checkArgument(superclass instanceof ParameterizedType, "%s isn't parameterized", superclass);

    assertAssignable(
        TypeToken.of(new TypeCapture<L>() {}.capture()),
        TypeToken.of(new TypeCapture<L>() {}.capture()));
    assertNotAssignable(
        TypeToken.of(new TypeCapture<R>() {}.capture()),
        TypeToken.of(new TypeCapture<L>() {}.capture()));
    assertAssignable(TypeToken.of(new TypeCapture<L>() {}.capture()), new TypeToken<List<R>>() {});
  }

        new TypeResolver()
            .where(
                new TypeCapture<Iterable<Map<?, V>>>() {}.capture(),
                new TypeCapture<Iterable<Map<String, Integer>>>() {}.capture());
    assertEquals(
        new TypeCapture<K>() {}.capture(), resolver.resolveType(new TypeCapture<K>() {}.capture()));
    assertEquals(Integer.class, resolver.resolveType(new TypeCapture<V>() {}.capture()));
  }

        new TypeResolver()
            .where(
                new TypeCapture<Iterable<Map<?, V>>>() {}.capture(),
                new TypeCapture<Iterable<Map<String, Integer>>>() {}.capture());
    assertEquals(
        new TypeCapture<K>() {}.capture(), resolver.resolveType(new TypeCapture<K>() {}.capture()));
    assertEquals(Integer.class, resolver.resolveType(new TypeCapture<V>() {}.capture()));
  }

    ParameterizedType jvmType =
        (ParameterizedType) new TypeCapture<Entry<String, int[][]>>() {}.capture();
    ParameterizedType ourType =
        Types.newParameterizedTypeWithOwner(Map.class, Entry.class, String.class, int[][].class);

    new EqualsTester()
        .addEqualityGroup(jvmType, ourType)
        .addEqualityGroup(new TypeCapture<Entry<String, String>>() {}.capture())

    assertAssignable(
        TypeToken.of(new TypeCapture<L>() {}.capture()),
        TypeToken.of(new TypeCapture<L>() {}.capture()));
    assertNotAssignable(
        TypeToken.of(new TypeCapture<R>() {}.capture()),
        TypeToken.of(new TypeCapture<L>() {}.capture()));
    assertAssignable(TypeToken.of(new TypeCapture<L>() {}.capture()), new TypeToken<List<R>>() {});
  }

    ParameterizedType jvmType =
        (ParameterizedType) new TypeCapture<Entry<String, int[][]>>() {}.capture();
    ParameterizedType ourType =
        Types.newParameterizedTypeWithOwner(Map.class, Entry.class, String.class, int[][].class);

    new EqualsTester()
        .addEqualityGroup(jvmType, ourType)
        .addEqualityGroup(new TypeCapture<Entry<String, String>>() {}.capture())

  }

  public <T> void testVisitGenericArrayType() {
    Type type = new TypeCapture<T[]>() {}.capture();
    assertVisited(type);
    new BaseTypeVisitor() {
      @Override
      void visitGenericArrayType(GenericArrayType t) {}
    }.visit(type);
  }

  public <T> void testVisitParameterizedType() {
    Type type = new TypeCapture<Iterable<T>>() {}.capture();
    assertVisited(type);
    new BaseTypeVisitor() {

  }

  public <T> void testVisitGenericArrayType() {
    Type type = new TypeCapture<T[]>() {}.capture();
    assertVisited(type);
    new BaseTypeVisitor() {
      @Override
      void visitGenericArrayType(GenericArrayType t) {}
    }.visit(type);
  }

  public <T> void testVisitParameterizedType() {
    Type type = new TypeCapture<Iterable<T>>() {}.capture();
    assertVisited(type);
    new BaseTypeVisitor() {

        public Type[] getActualTypeArguments() {
          return new Type[] {new TypeCapture<P>() {}.capture()};
        }

        @Override
        public Type getOwnerType() {
          return new TypeCapture<O>() {}.capture();
        }

        @Override
        public Type getRawType() {
          return new TypeCapture<T>() {}.capture();
        }
      };
    }
  }