src/com/google/inject/servlet/ServletModule.java

/**
 * Copyright (C) 2006 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.inject.servlet;

import com.google.inject.AbstractModule;
import com.google.inject.TypeLiteral;
import com.google.inject.Factory;
import com.google.inject.Context;
import static com.google.inject.servlet.ServletScopes.REQUEST;
import static com.google.inject.servlet.ServletScopes.SESSION;

import java.util.Map;

import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

/**
 * Configures the servlet scopes and creates bindings for the servlet API
 * objects so you can inject the request, response, session, etc.
 *
 * @author crazybob@google.com (Bob Lee)
 */
public class ServletModule extends AbstractModule {

  protected void configure() {
    // Scopes.
    scope(RequestScoped.class, REQUEST);
    scope(SessionScoped.class, SESSION);

    // Bind request.
    Factory<HttpServletRequest> requestFactory =
        new Factory<HttpServletRequest>() {
          public HttpServletRequest generate(Context context) {
            return GuiceFilter.getRequest();
          }

          public String toString() {
            return "RequestFactory";
          }
        };
    bind(HttpServletRequest.class).to(requestFactory);
    bind(ServletRequest.class).to(requestFactory);

    // Bind response.
    Factory<HttpServletResponse> responseFactory =
        new Factory<HttpServletResponse>() {
          public HttpServletResponse generate(Context context) {
            return GuiceFilter.getResponse();
          }

          public String toString() {
            return "ResponseFactory";
          }
        };
    bind(HttpServletResponse.class).to(responseFactory);
    bind(ServletResponse.class).to(responseFactory);

    // Bind session.
    bind(HttpSession.class).to(new Factory<HttpSession>() {
      public HttpSession generate(Context context) {
        return GuiceFilter.getRequest().getSession();
      }

      public String toString() {
        return "SessionFactory";
      }
    });

    // Bind request parameters.
    bind(new TypeLiteral<Map<String, String[]>>() {})
        .annotatedWith(RequestParameters.class)
        .to(new Factory<Map<String, String[]>>() {
              @SuppressWarnings({"unchecked"})
              public Map<String, String[]> generate(Context context) {
                return GuiceFilter.getRequest().getParameterMap();
              }

              public String toString() {
                return "RequestParametersFactory";
              }
            });
  }
}