Dynamic Filter Binding

What is Dynamic Filter Binding?

Bind filters to resource methods programmatically during the app initialization time.

Components

  1. Filter
  2. DynamicFeature
  3. Resource

Filter

  • implements ContainerRequestFilter, ContainerResponseFilter
  • override filter method
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public class LogFilter implements ContainerRequestFilter, ContainerResponseFilter {

  @Override
  public void filter(ContainerRequestContext reqContext) throws IOException {
      log(reqContext.getUriInfo(), reqContext.getHeaders());

  }

  @Override
  public void filter(ContainerRequestContext reqContext,
                     ContainerResponseContext resContext) throws IOException {
      log(reqContext.getUriInfo(), resContext.getHeaders());


  }

  private void log(UriInfo uriInfo, MultivaluedMap<String, ?> headers) {
      System.out.println("Path: " + uriInfo.getPath());
      headers.entrySet().forEach(h -> System.out.println(h.getKey() + ": " + h.getValue()));
  }
}

DynamicFeature

  • @Provider
  • implements DynamicFeature
  • override configure to register filter (only works for path ‘/order’)
  • bind filter with resource
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@Provider
public class FilterRegistrationFeature implements DynamicFeature {
  @Override
  public void configure(ResourceInfo resourceInfo, FeatureContext context) {
      if (MyResource.class.isAssignableFrom(resourceInfo.getResourceClass())) {
          Method method = resourceInfo.getResourceMethod();
          if (method.getName().toLowerCase().contains("order")) {
              context.register(new LogFilter());
          }
      }
  }
}

Resource

Define path and verb.

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@Path("")
public class MyResource {

  @GET
  @Path("customers")
  public String getAllCustomers() {
      System.out.println("in getAllCustomers()");
      return "dummy-response for all customers";
  }

  @GET
  @Path("customers/{id}")
  public String getCustomerById(@PathParam("id") String id) {
      System.out.println("in getCustomerById()");
      return "dummy-response for customer " + id;
  }

  @GET
  @Path("orders")
  public String getOrders() {
      System.out.println("in getOrders()");
      return "dummy-response for orders";
  }
}

References

https://www.logicbig.com/tutorials/java-ee-tutorial/jax-rs/filters-dynamic-binding.html