package com.atlassian.plugin.servlet;
   
   import com.atlassian.plugin.servlet.descriptors.ServletModuleDescriptor;
   import com.atlassian.plugin.util.ClassLoaderStack;
   
   import javax.servlet.ServletConfig;
   import javax.servlet.ServletContext;
   import javax.servlet.ServletException;
   import javax.servlet.http.HttpServlet;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  import java.io.IOException;
  import java.util.Enumeration;
  
  /**
   * We are wrapping the plugins servlet in another servlet so that we can set some things up before
   * the plugins servlet is called. Currently we do the following:
   * <ul>
   * <li>the Threads classloader to the plugins classloader)</li>
   * <li>wrap the request so that path info is right for the servlets</li>
   * </ul>
   */
  public class DelegatingPluginServlet extends HttpServlet {
      private final ServletModuleDescriptor descriptor;
  
      private final HttpServlet servlet;
  
      public DelegatingPluginServlet(final ServletModuleDescriptor descriptor) {
          this.descriptor = descriptor;
          servlet = descriptor.getModule();
      }
  
      @Override
      public void service(final HttpServletRequest req, final HttpServletResponse res) throws ServletException, IOException {
          ClassLoaderStack.push(descriptor.getPlugin().getClassLoader());
          try {
              servlet.service(new PluginHttpRequestWrapper(req, descriptor), res);
          } finally {
              ClassLoaderStack.pop();
          }
      }
  
      @Override
      public void init(final ServletConfig config) throws ServletException {
          ClassLoaderStack.push(descriptor.getPlugin().getClassLoader());
          try {
              servlet.init(config);
          } finally {
              ClassLoaderStack.pop();
          }
      }
  
      @Override
      public void destroy() {
          ClassLoaderStack.push(descriptor.getPlugin().getClassLoader());
          try {
              servlet.destroy();
          } finally {
              ClassLoaderStack.pop();
          }
      }
  
      @Override
      public boolean equals(final Object obj) {
          return servlet.equals(obj);
      }
  
      @Override
      public String getInitParameter(final String name) {
          return servlet.getInitParameter(name);
      }
  
      @Override
      public Enumeration<String> getInitParameterNames() {
          @SuppressWarnings("unchecked")
          final Enumeration<String> initParameterNames = servlet.getInitParameterNames();
          return initParameterNames;
      }
  
      @Override
      public ServletConfig getServletConfig() {
          return servlet.getServletConfig();
      }
  
      @Override
      public ServletContext getServletContext() {
          return servlet.getServletContext();
      }
  
      @Override
      public String getServletInfo() {
          return servlet.getServletInfo();
      }
  
      @Override
      public String getServletName() {
          return servlet.getServletName();
      }
  
     @Override
     public int hashCode() {
         return servlet.hashCode();
     }
 
     @Override
     public void init() throws ServletException {
         servlet.init();
     }
 
     @Override
     public void log(final String message, final Throwable t) {
         servlet.log(message, t);
     }
 
     @Override
     public void log(final String msg) {
         servlet.log(msg);
     }
 
     @Override
     public String toString() {
         return servlet.toString();
     }
 
     public ServletModuleDescriptor getModuleDescriptor() {
         return descriptor;
     }
 
     HttpServlet getDelegatingServlet() {
         return servlet;
     }
 }