Generated TypeAdapterFactory and null safety

[muddin1]

As of 0.2.5, My custom AutoValueTypeAdapterFactory would call nullSafe() on every type adapter I return in the create() method. Refer #28 (comment).

Class<? super T> rawType = type.getRawType();
if (rawType.equals(User.class)) {
    return (TypeAdapter<T>) User.typeAdapter(gson).nullSafe();
}

Beginning from 0.3.0, the generated AutoValueGsonTypeAdapterFactory does not call nullSafe() by default, which is the appropriate way for sure.

So, how'd I go about ensuring null-safety when using the generated TypeAdapterFactory.

[rharter]

You could submit a PR if you've got the code. Otherwise I'll have to add that.

[muddin1]

Are you saying that we should attach nullSafe() to every AutoValue typeAdapter mentioned in the generated Factory i.e. in the annotation processor?

Also, there's this PR #23 that presumably eliminates the need to use nullSafe() completely.

[jachenry]

Below is a quick solution for anyone else that hits this before #23 is completed.

@GsonTypeAdapterFactory
public abstract class AutoValueAdapterFactory implements TypeAdapterFactory {

  public static TypeAdapterFactory create() {
    final TypeAdapterFactory factory = new AutoValueGson_AutoValueAdapterFactory();

    return new TypeAdapterFactory() {
      @Override
      public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> type) {
        TypeAdapter<T> typeAdapter = factory.create(gson, type);
        return typeAdapter != null ? typeAdapter.nullSafe() : null;
      }
    };
  }
}

[muddin1]

@jachenry Thanks, I've been doing the same.

[jjimenez0611]

Hi @jachenry

Please can you explain to me with more details..

I have my factory like this:

public class AutoValueGsonTyeAdapterFactory implements TypeAdapterFactory {

public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> type) {
    Class<? super T> rawType = type.getRawType();

    if (rawType.equals(MGuest.class)) {
        return (TypeAdapter<T>) MGuest.typeAdapter(gson);
    }

    if(rawType.equals(MTicket.class)){
        return (TypeAdapter<T>) MTicket.typeAdapter(gson);
    }

    return null;
}

}

Then I have your abstract class that contains my class

@GsonTypeAdapterFactory
public abstract class AutoValueAdapterFactory implements TypeAdapterFactory {

public static TypeAdapterFactory create() {
    final TypeAdapterFactory factory = new **AutoValueGsonTyeAdapterFactory();**

    return new TypeAdapterFactory() {
        @Override
        public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> type) {
            TypeAdapter<T> typeAdapter = factory.create(gson, type);
            return typeAdapter != null ? typeAdapter.nullSafe() : null;
        }
    };
}

}

And finally I need to call this classes in my GsonConverterFactory, but in this point I really don't now how to call the abstract class...

public static GsonConverterFactory gsonConverterFactory = GsonConverterFactory.create(
new GsonBuilder()
.registerTypeAdapterFactory(MyTypeAdapterFactory)
.create());

Can you help me in this last step?

[jachenry]

@jjimenez0611 You'll want to call the static create() method on AutoValueAdapterFactory.

@GsonTypeAdapterFactory
public abstract class AutoValueAdapterFactory implements TypeAdapterFactory {

public static TypeAdapterFactory create() {
    final TypeAdapterFactory factory = new AutoValueGson_AutoValueAdapterFactory();

    return new TypeAdapterFactory() {
        @Override
        public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> type) {
            TypeAdapter<T> typeAdapter = factory.create(gson, type);
            return typeAdapter != null ? typeAdapter.nullSafe() : null;
        }
    };
}

new GsonBuilder()
    .registerTypeAdapterFactory(AutoValueAdapterFactory.create())
    .create()

[jjimenez0611]

@jachenry, thanks I really appreciate your help, now I understand.

[ZacSweers]

Closed by #78