16. 404 page

When Utterlyidle can't find a binding that matches your HTTP request, it generates a default match failure page with a 404 response code and a list of suggestions. It's a very useful feature e.g when you misspelled a query param name. If you want to exclude some bindings from showing up in the suggestions list, you can use a @Hidden annotation or a hidden() method on a DSL binding. When you put your application on a public web you may want to disable the default match failure page.

Here's the code for the custom MatchFailure renderer:

import com.googlecode.utterlyidle.MatchFailure;
import com.googlecode.utterlyidle.Renderer;
import com.googlecode.utterlyidle.handlers.RenderingResponseHandler;
import com.googlecode.utterlyidle.handlers.ResponseHandlers;
import com.googlecode.utterlyidle.modules.ResponseHandlersModule;

import static com.googlecode.totallylazy.Predicates.*;
import static com.googlecode.utterlyidle.handlers.HandlerRule.entity;
import static com.googlecode.utterlyidle.handlers.RenderingResponseHandler.renderer;

public class MatchFailureModule implements ResponseHandlersModule {

    @Override
    public ResponseHandlers addResponseHandlers(ResponseHandlers handlers) throws Exception {
        handlers.add(where(entity(), is(instanceOf(MatchFailure.class))), customFailureRenderer());
        return handlers;
    }

    private RenderingResponseHandler<Object> customFailureRenderer() {
        return renderer(new Renderer<Object>() {
            @Override
            public String render(Object value) throws Exception {
                return "404 - Not Found";
            }
        });
    }
}