TypeToken.java 文件源码

/**
 * Returns the generic form of {@code superclass}. For example, if this is
 * {@code ArrayList<String>}, {@code Iterable<String>} is returned given the input
 * {@code Iterable.class}.
 */
public final TypeToken<? super T> getSupertype(Class<? super T> superclass) {
  checkArgument(
      this.someRawTypeIsSubclassOf(superclass),
      "%s is not a super class of %s",
      superclass,
      this);
  if (runtimeType instanceof TypeVariable) {
    return getSupertypeFromUpperBounds(superclass, ((TypeVariable<?>) runtimeType).getBounds());
  }
  if (runtimeType instanceof WildcardType) {
    return getSupertypeFromUpperBounds(superclass, ((WildcardType) runtimeType).getUpperBounds());
  }
  if (superclass.isArray()) {
    return getArraySupertype(superclass);
  }
  @SuppressWarnings("unchecked") // resolved supertype
  TypeToken<? super T> supertype =
      (TypeToken<? super T>) resolveSupertype(toGenericType(superclass).runtimeType);
  return supertype;
}