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Routing and parameters

Mateu lets you define routes declaratively and automatically bind URL parameters to your ViewModel.

This means:

  • no controllers
  • no manual parsing
  • no mapping layer

The URL becomes part of your UI state.

Path parameters

You can define parameters directly in the route using placeholders.

@Route("/example/:name")
public class ExampleParametersViewModel {

    String name;

}

When navigating to:

/example/Mateu

Mateu automatically sets:

name = "Mateu";

Query parameters

Mateu also maps query parameters automatically.

int version;

When navigating to:

/example/Mateu?version=1

Mateu sets:

version = 1;

Full example

@Route("/example/:name")
public class ExampleParametersViewModel {

    String name;

    int version;

    @ReadOnly
    String assessment;

    @Button
    void check() {
        assessment = "name= " + name + ", version=" + version;
    }

}

URL:

http://localhost:8080/example/Mateu?version=1

Result:

  • name = "Mateu"
  • version = 1

What this enables

This approach removes an entire layer from traditional architectures.

Instead of:

  • controller → parse params
  • map to DTO
  • pass to UI

You get:

  • URL → ViewModel (directly)

Mental model

  • route → defines the screen
  • path params → map to fields
  • query params → map to fields
  • ViewModel → receives everything

👉 The URL is just another input to your UI state.

When to use this

Use routing and parameters when:

  • you want shareable URLs
  • you need deep linking
  • you want to preload UI state
  • you want navigation without controllers

Notes

  • field names must match parameter names
  • Mateu handles type conversion automatically
  • missing parameters use default values

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