/*
 * Copyright (C) 2008 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.ImplementedBy;
import java.io.IOException;
import javax.servlet.FilterChain;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;

/**
 * A dispatcher abstraction for guice-servlet registered servlets and filters. By default, we assume a
 * Guice 1.0 style servlet module is in play. In other words, we dispatch directly to the web.xml
 * pipeline after setting up scopes.
 *
 * <p>If on the other hand, {@link ServletModule} is used to register managed servlets and/or
 * filters, then a different pipeline is bound instead. Which, after dispatching to Guice-injected
 * filters and servlets continues to the web.xml pipeline (if necessary).
 *
 * @author dhanji@gmail.com (Dhanji R. Prasanna)
 */
@ImplementedBy(DefaultFilterPipeline.class)
public interface FilterPipeline {

  /**
   * Initializes the pipeline, putting it into service.
   * 
   * @param context of the web application
   */
  void initPipeline(ServletContext context) throws ServletException;

  /**
   * Destroys the pipeline, taking it out of service.
   */
  void destroyPipeline();

  /**
   * Dispatches a request against the pipeline.
   * 
   * @param request to dispatch
   * @param response to populate
   * @param defaultFilterChain for last resort filtering
   */
  void dispatch(ServletRequest request, ServletResponse response, FilterChain defaultFilterChain)
      throws IOException, ServletException;
}