Re: I am a user of @FreeBuilder

[Chris Purcell]

Hi Colin!

Sorry about the default package issue. FreeBuilder cannot work in the default package as it needs to make cross-class references, but the error message definitely needs fixing. This exact issue was raised a few days ago: https://github.com/google/FreeBuilder/issues/85

Unfortunately, Builder inheritance is not currently supported in FreeBuilder. It's on the long-term agenda, but that won't be much use to you right now! One option you have is to use composition rather than inheritance: that is, add a getter method returning a BaseModelParameters instance rather than inheriting from BaseModelParameters. Some argue that this is always the correct approach, though I personally disagree.

If you still prefer inheritance, then consider making an interface with a default setB implementation that all your ModelParameters builders can implement:

//@FreeBuilder <-- not used any more
public interface BaseModelParameters {
   ...
    interface BaseBuilder<B extends BaseBuilder<B>> {
        B setA(String a);
        default B setB(String b) {
            return setA("transform from " + b);
        }
    }
}

@FreeBuilder
public interface ConcreteModelParameters {
    String getD();
    class Builder extends ConcreteModelParameters_Builder
            implements BaseBuilder<Builder> {}
}

If you want to know what FreeBuilder is generating, you should be able to read the generated source code. Try looking in the "target" directory if you're using a command-line build tool like maven. If you're using Eclipse, you'll need to configure the generated source directory (Project > Properties > Java Compiler > Annotation Processing) to not start with a period, as otherwise Eclipse hides it by default.

Hope that helps!

Chris

On Fri, 30 Oct 2015 03:50 ZhongQi <jales...@gmail.com> wrote:

Hi Chris,

Thanks for your tool. I tried it out in my project, here is some feedback.

1. There is a bug, the builder interface can not live under default package, compile error.

2. In my use case, there is a list of builders.

I have a BaseBuilder containing some fields, one field A is getting from another field B.

In the code without using FreeBuilder, in the setting method of B, I do some transform of B, and set the value of A.

Then there are a list of Builders which are subclasses of BaseBuilder, they have their own fields.

Because the override method on BaseBuilder can not be inherited to SubBuilders, I am using the feature of default method in JAVA 8 to achieve it.

Here is the code.

I don't think move the code in getB() to an override method in Builder is good, since interface extends it can not use it.

Maybe you have better thoughts to do it.

@FreeBuilder
public interface BaseModelParameters {
    String getA();

    default String getB() {
        return "transform from " + getA();
    }

    Optional<Boolean> getC();

    class Builder extends BaseModelParameters_Builder {}
}

@FreeBuilder
public interface ConcreteModelParameters extends BaseModelParameters {
    String getD();

    class Builder extends ConcreteModelParameters_Builder {}
}

Would you be able to let me know how to debug the source code? This project is different, there is not main() method.

Thanks,

Colin