JerseyUtil.java

package com.hubspot.dropwizard.guice;

import com.google.inject.Injector;
import com.google.inject.Key;
import com.google.inject.servlet.GuiceFilter;
import io.dropwizard.jersey.setup.JerseyEnvironment;
import io.dropwizard.setup.Environment;
import org.glassfish.jersey.server.model.Resource;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.ws.rs.Path;
import java.lang.reflect.Type;

/**
 * Functionality used to help link Guice with Jersey
 */
public class JerseyUtil {

  private static final Logger logger = LoggerFactory.getLogger(JerseyUtil.class);

  /**
   * Registers any Guice-bound providers or root resources.
   */
  public static void registerGuiceBound(Injector injector, final JerseyEnvironment environment) {
    while (injector != null) {
      for (Key<?> key : injector.getBindings().keySet()) {
        Type type = key.getTypeLiteral().getType();
        if (type instanceof Class) {
          Class<?> c = (Class) type;
          if (isProviderClass(c)) {
            logger.info("Registering {} as a provider class", c.getName());
            environment.register(c);
          } else if (isRootResourceClass(c)) {
            // Jersey rejects resources that it doesn't think are acceptable
            // Including abstract classes and interfaces, even if there is a valid Guice binding.
            if(Resource.isAcceptable(c)) {
              logger.info("Registering {} as a root resource class", c.getName());
              environment.register(c);
            } else {
              logger.warn("Class {} was not registered as a resource. Bind a concrete implementation instead.", c.getName());
            }
          }

        }
      }
      injector = injector.getParent();
    }
  }

  private static boolean isProviderClass(Class<?> c) {
    return c != null && c.isAnnotationPresent(javax.ws.rs.ext.Provider.class);
  }

  private static boolean isRootResourceClass(Class<?> c) {
    if (c == null) {
      return false;
    }

    if (c.isAnnotationPresent(Path.class)) {
      return true;
    }

    for (Class i : c.getInterfaces()) {
      if (i.isAnnotationPresent(Path.class)) {
        return true;
      }
    }

    return false;
  }

  public static void registerGuiceFilter(Environment environment) {
    environment.servlets().addFilter("Guice Filter", GuiceFilter.class)
           .addMappingForUrlPatterns(null, false, "/*");
  }
}