<button onClick="@command('handle', format='USD', price=9.99, id=3)"/>

@Command
public void handle(@BindingParam("format") String format, @BindingParam("price") double price, @BindingParam("id") int id) {
}

public class Product {
  private String format;
  private double price;
  private int id;
  // Getters and setters are omitted
}

@Command
public void handle(@BindingParams Product product) {
  // product.getFormat(), product.getPrice(), product.getId() ...
}