content: /**
   * 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 org.apache.aurora.scheduler.http;
  
  import java.io.IOException;
  
  import javax.servlet.Filter;
  import javax.servlet.FilterChain;
  import javax.servlet.FilterConfig;
  import javax.servlet.ServletException;
  import javax.servlet.ServletRequest;
  import javax.servlet.ServletResponse;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  
  /**
   * A base class for a filter that expects HTTP requests. This allows filter implementations to
   * avoid no-op implementations and casting to HTTP request and response types.
   */
  public abstract class AbstractFilter implements Filter {
  
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
      // No-op.
    }
  
    @Override
    public void doFilter(
        ServletRequest request,
        ServletResponse response,
        FilterChain chain) throws IOException, ServletException {
  
      doFilter((HttpServletRequest) request, (HttpServletResponse) response, chain);
    }
  
    protected abstract void doFilter(
        HttpServletRequest request,
        HttpServletResponse response,
        FilterChain chain) throws IOException, ServletException;
  
    @Override
    public void destroy() {
      // No-op.
    }
  }
  