QueryStringBindable for a custom enum

Question

I've defined an enum type Format that implements QueryStringBindable. I think I've implemented it correctly, but in my routes file, I can't specify my type as a route parameter, because the compiler can't find it, and I have no idea how to import it into the routes file.

Here's the enum:

package web;

import java.util.Map;

import play.libs.F;
import play.mvc.QueryStringBindable;

public enum Format implements QueryStringBindable<Format> {
    Html,
    Pdf,
    Csv;

    private Format value;

    @Override
    public F.Option<Format> bind(String key, Map<String, String[]> data) {
        String[] vs = data.get(key);
        if (vs != null && vs.length > 0) {
            String v = vs[0];
            value = Enum.valueOf(Format.class, v);
            return F.Option.Some(value);
        }
        return F.Option.None();
    }

    @Override
    public String unbind(String key) {
        return key + "=" + value;
    }

    @Override
    public String javascriptUnbind() {
         return value.toString();
    }
}

And here's my route:

GET     /deposits                                    controllers.Deposits.index(selectedAccountKey: Long ?= 0, format: Format ?= Format.Html)

How can I tell the compiler about my enum? Thanks!

Edit

I've also tried adding the path to the type in Build.scala as has been recommended in other posts:

val main = PlayProject(appName, appVersion, appDependencies, mainLang = JAVA).settings(
  routesImport += "web.Format",
  resolvers += Resolver.url("My GitHub Play Repository", url("http://www.joergviola.de/releases/"))(Resolver.ivyStylePatterns)
)

I changed that and restarted my server, but it appears to make no difference whatsoever.

Answer 1

I had the same problem and I finally found out that it is not solvable as is.

By reading the documentation for PathBindable and QueryStringBindable I found that play framework requires the Bindable to provide a No Argument public constructor. Which by definition is no possible with enum in Java.

I'd like to offer you the same solution I gave another (more recent) question. I just wrapped the enum into a small Wrapper class that implements QueryStringBindable or PathBindable.

play framework - bind enum in routes