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Routing

In modern web applications, routing refers to the process of managing navigation between different views or components based on the current URL or path. In webforJ, routing establishes a sophisticated framework for client-side navigation, where UI updates happen dynamically without requiring full page reloads, enhancing the performance of your app.

Traditional vs client-side routing​

In traditional server-side routing, when a user clicks a link, the browser sends a request to the server for a new document. The server responds by sending a fresh HTML page, which forces the browser to re-evaluate CSS and JavaScript, re-render the entire document, and reset the app state. This cycle introduces delays and inefficiencies, as the browser must reload resources and the page state. The process typically involves:

  1. Request: The user navigates to a new URL, triggering a request to the server.
  2. Response: The server sends back a new HTML document along with related assets (CSS, JS).
  3. Rendering: The browser re-renders the entire page, often losing the state of previously loaded pages.

This approach can lead to performance bottlenecks and suboptimal user experiences due to repeated full-page reloads.

Client-Side Routing in webforJ solves this by enabling navigation directly in the browser, dynamically updating the UI without sending a new request to the server. Here's how it works:

  1. Single Initial Request: The browser loads the app once, including all required assets (HTML, CSS, JavaScript).
  2. URL Management: The router listens for URL changes and updates the view based on the current route.
  3. Dynamic Component Rendering: The router maps the URL to a component and renders it dynamically, without refreshing the page.
  4. State Preservation: The state of the app is maintained between navigations, ensuring smooth transition between views.

This design enables deep linking and URL-driven state management, allowing users to bookmark and share specific pages within the app while enjoying a smooth, single-page experience.

Core principles​

  • URL-Based Component Mapping: In webforJ, routes are directly tied to UI components. A URL pattern is mapped to a specific component, dictating what content is displayed based on the current path.
  • Declarative Routing: Routes are defined declaratively, typically using annotations. Each route corresponds to a component that is rendered when the route is matched.
  • Dynamic Navigation: The router dynamically switches between views without reloading the page, keeping the app responsive and fast.

Example of client-side routing in webforJ​

Here’s an example of defining a route for a UserProfileView component to display user details based on the id parameter in the URL:

@Route(value = "user/:id")
public class UserProfileView extends Composite<Div> implements DidEnterObserver {

  @Override
  public void onDidEnter(DidEnterEvent event, ParametersBag parameters) {
    String id = parameters.getAlpha("id").orElse("");
    refreshProfile(id);
  }
}

In this setup:

  • Navigating to /user/john would render the UserProfileView component.
  • The id parameter would capture john from the URL and allow you to use it within the component to fetch and display user data.

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