/*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you 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 javax.servlet.http;
  
  import java.io.IOException;
  import java.io.PrintWriter;
  import java.io.OutputStreamWriter;
  import java.io.UnsupportedEncodingException;
  import java.lang.reflect.Method;
  import java.text.MessageFormat;
  import java.util.Enumeration;
  import java.util.Locale;
  import java.util.ResourceBundle;
  
  import javax.servlet.GenericServlet;
  import javax.servlet.ServletException;
  import javax.servlet.ServletOutputStream;
  import javax.servlet.ServletRequest;
  import javax.servlet.ServletResponse;
  
  
  /**
   *
   * Provides an abstract class to be subclassed to create
   * an HTTP servlet suitable for a Web site. A subclass of
   * <code>HttpServlet</code> must override at least 
   * one method, usually one of these:
   *
   * <ul>
   * <li> <code>doGet</code>, if the servlet supports HTTP GET requests
   * <li> <code>doPost</code>, for HTTP POST requests
   * <li> <code>doPut</code>, for HTTP PUT requests
   * <li> <code>doDelete</code>, for HTTP DELETE requests
   * <li> <code>init</code> and <code>destroy</code>, 
   * to manage resources that are held for the life of the servlet
   * <li> <code>getServletInfo</code>, which the servlet uses to
   * provide information about itself 
   * </ul>
   *
   * <p>There's almost no reason to override the <code>service</code>
   * method. <code>service</code> handles standard HTTP
   * requests by dispatching them to the handler methods
   * for each HTTP request type (the <code>do</code><i>XXX</i>
   * methods listed above).
   *
   * <p>Likewise, there's almost no reason to override the 
   * <code>doOptions</code> and <code>doTrace</code> methods.
   * 
   * <p>Servlets typically run on multithreaded servers,
   * so be aware that a servlet must handle concurrent
   * requests and be careful to synchronize access to shared resources.
   * Shared resources include in-memory data such as
   * instance or class variables and external objects
   * such as files, database connections, and network 
   * connections.
   * See the
   * <a href="http://java.sun.com/Series/Tutorial/java/threads/multithreaded.html">
   * Java Tutorial on Multithreaded Programming</a> for more
   * information on handling multiple threads in a Java program.
   *
   * @author	Various
   * @version	$Version$
   *
   */
  
  
  
  public abstract class HttpServlet extends GenericServlet
      implements java.io.Serializable
  {
      private static final String METHOD_DELETE = "DELETE";
      private static final String METHOD_HEAD = "HEAD";
      private static final String METHOD_GET = "GET";
      private static final String METHOD_OPTIONS = "OPTIONS";
      private static final String METHOD_POST = "POST";
      private static final String METHOD_PUT = "PUT";
      private static final String METHOD_TRACE = "TRACE";
  
      private static final String HEADER_IFMODSINCE = "If-Modified-Since";
      private static final String HEADER_LASTMOD = "Last-Modified";
      
      private static final String LSTRING_FILE =
 	"javax.servlet.http.LocalStrings";
     private static ResourceBundle lStrings =
 	ResourceBundle.getBundle(LSTRING_FILE);
    
    
    
     
     /**
      * Does nothing, because this is an abstract class.
      * 
      */
 
     public HttpServlet() { }
     
     
 
     /**
      *
      * Called by the server (via the <code>service</code> method) to
      * allow a servlet to handle a GET request. 
      *
      * <p>Overriding this method to support a GET request also
      * automatically supports an HTTP HEAD request. A HEAD
      * request is a GET request that returns no body in the
      * response, only the request header fields.
      *
      * <p>When overriding this method, read the request data,
      * write the response headers, get the response's writer or 
      * output stream object, and finally, write the response data.
      * It's best to include content type and encoding. When using
      * a <code>PrintWriter</code> object to return the response,
      * set the content type before accessing the
      * <code>PrintWriter</code> object.
      *
      * <p>The servlet container must write the headers before
      * committing the response, because in HTTP the headers must be sent
      * before the response body.
      *
      * <p>Where possible, set the Content-Length header (with the
      * {@link javax.servlet.ServletResponse#setContentLength} method),
      * to allow the servlet container to use a persistent connection 
      * to return its response to the client, improving performance.
      * The content length is automatically set if the entire response fits
      * inside the response buffer.
      *
      * <p>When using HTTP 1.1 chunked encoding (which means that the response
      * has a Transfer-Encoding header), do not set the Content-Length header.
      *
      * <p>The GET method should be safe, that is, without
      * any side effects for which users are held responsible.
      * For example, most form queries have no side effects.
      * If a client request is intended to change stored data,
      * the request should use some other HTTP method.
      *
      * <p>The GET method should also be idempotent, meaning
      * that it can be safely repeated. Sometimes making a
      * method safe also makes it idempotent. For example, 
      * repeating queries is both safe and idempotent, but
      * buying a product online or modifying data is neither
      * safe nor idempotent. 
      *
      * <p>If the request is incorrectly formatted, <code>doGet</code>
      * returns an HTTP "Bad Request" message.
      * 
      *
      * @param req	an {@link HttpServletRequest} object that
      *			contains the request the client has made
      *			of the servlet
      *
      * @param resp	an {@link HttpServletResponse} object that
      *			contains the response the servlet sends
      *			to the client
      * 
      * @exception IOException	if an input or output error is 
      *				detected when the servlet handles
      *				the GET request
      *
      * @exception ServletException	if the request for the GET
      *					could not be handled
      *
      * 
      * @see javax.servlet.ServletResponse#setContentType
      *
      */
 
     protected void doGet(HttpServletRequest req, HttpServletResponse resp)
 	throws ServletException, IOException
     {
 	String protocol = req.getProtocol();
 	String msg = lStrings.getString("http.method_get_not_supported");
 	if (protocol.endsWith("1.1")) {
 	    resp.sendError(HttpServletResponse.SC_METHOD_NOT_ALLOWED, msg);
 	} else {
 	    resp.sendError(HttpServletResponse.SC_BAD_REQUEST, msg);
 	}
     }
 
 
 
 
 
     /**
      *
      * Returns the time the <code>HttpServletRequest</code>
      * object was last modified,
      * in milliseconds since midnight January 1, 1970 GMT.
      * If the time is unknown, this method returns a negative
      * number (the default).
      *
      * <p>Servlets that support HTTP GET requests and can quickly determine
      * their last modification time should override this method.
      * This makes browser and proxy caches work more effectively,
      * reducing the load on server and network resources.
      *
      *
      * @param req	the <code>HttpServletRequest</code> 
      *			object that is sent to the servlet
      *
      * @return		a <code>long</code> integer specifying
      *			the time the <code>HttpServletRequest</code>
      *			object was last modified, in milliseconds
      *			since midnight, January 1, 1970 GMT, or
      *			-1 if the time is not known
      *
      */
 
     protected long getLastModified(HttpServletRequest req) {
 	return -1;
     }
 
 
 
 
     /**
      * 
      *
      * <p>Receives an HTTP HEAD request from the protected
      * <code>service</code> method and handles the
      * request.
      * The client sends a HEAD request when it wants
      * to see only the headers of a response, such as
      * Content-Type or Content-Length. The HTTP HEAD
      * method counts the output bytes in the response
      * to set the Content-Length header accurately.
      *
      * <p>If you override this method, you can avoid computing
      * the response body and just set the response headers
      * directly to improve performance. Make sure that the
      * <code>doHead</code> method you write is both safe
      * and idempotent (that is, protects itself from being
      * called multiple times for one HTTP HEAD request).
      *
      * <p>If the HTTP HEAD request is incorrectly formatted,
      * <code>doHead</code> returns an HTTP "Bad Request"
      * message.
      *
      *
      * @param req	the request object that is passed
      *			to the servlet
      *			
      * @param resp	the response object that the servlet
      *			uses to return the headers to the clien
      *
      * @exception IOException		if an input or output error occurs
      *
      * @exception ServletException	if the request for the HEAD
      *					could not be handled
      */
 
     protected void doHead(HttpServletRequest req, HttpServletResponse resp)
 	throws ServletException, IOException
     {
 	NoBodyResponse response = new NoBodyResponse(resp);
 	
 	doGet(req, response);
 	response.setContentLength();
     }
     
 
 
 
 
     /**
      *
      * Called by the server (via the <code>service</code> method)
      * to allow a servlet to handle a POST request.
      *
      * The HTTP POST method allows the client to send
      * data of unlimited length to the Web server a single time
      * and is useful when posting information such as
      * credit card numbers.
      *
      * <p>When overriding this method, read the request data,
      * write the response headers, get the response's writer or output
      * stream object, and finally, write the response data. It's best 
      * to include content type and encoding. When using a
      * <code>PrintWriter</code> object to return the response, set the 
      * content type before accessing the <code>PrintWriter</code> object. 
      *
      * <p>The servlet container must write the headers before committing the
      * response, because in HTTP the headers must be sent before the 
      * response body.
      *
      * <p>Where possible, set the Content-Length header (with the
      * {@link javax.servlet.ServletResponse#setContentLength} method),
      * to allow the servlet container to use a persistent connection 
      * to return its response to the client, improving performance.
      * The content length is automatically set if the entire response fits
      * inside the response buffer.  
      *
      * <p>When using HTTP 1.1 chunked encoding (which means that the response
      * has a Transfer-Encoding header), do not set the Content-Length header. 
      *
      * <p>This method does not need to be either safe or idempotent.
      * Operations requested through POST can have side effects for
      * which the user can be held accountable, for example, 
      * updating stored data or buying items online.
      *
      * <p>If the HTTP POST request is incorrectly formatted,
      * <code>doPost</code> returns an HTTP "Bad Request" message.
      *
      *
      * @param req	an {@link HttpServletRequest} object that
      *			contains the request the client has made
      *			of the servlet
      *
      * @param resp	an {@link HttpServletResponse} object that
      *			contains the response the servlet sends
      *			to the client
      * 
      * @exception IOException	if an input or output error is 
      *				detected when the servlet handles
      *				the request
      *
      * @exception ServletException	if the request for the POST
      *					could not be handled
      *
      *
      * @see javax.servlet.ServletOutputStream
      * @see javax.servlet.ServletResponse#setContentType
      *
      *
      */
 
     protected void doPost(HttpServletRequest req, HttpServletResponse resp)
 	throws ServletException, IOException
     {
 	String protocol = req.getProtocol();
 	String msg = lStrings.getString("http.method_post_not_supported");
 	if (protocol.endsWith("1.1")) {
 	    resp.sendError(HttpServletResponse.SC_METHOD_NOT_ALLOWED, msg);
 	} else {
 	    resp.sendError(HttpServletResponse.SC_BAD_REQUEST, msg);
 	}
     }
 
 
 
 
     /**
      * Called by the server (via the <code>service</code> method)
      * to allow a servlet to handle a PUT request.
      *
      * The PUT operation allows a client to 
      * place a file on the server and is similar to 
      * sending a file by FTP.
      *
      * <p>When overriding this method, leave intact
      * any content headers sent with the request (including
      * Content-Length, Content-Type, Content-Transfer-Encoding,
      * Content-Encoding, Content-Base, Content-Language, Content-Location,
      * Content-MD5, and Content-Range). If your method cannot
      * handle a content header, it must issue an error message
      * (HTTP 501 - Not Implemented) and discard the request.
      * For more information on HTTP 1.1, see RFC 2616
      * <a href="http://www.ietf.org/rfc/rfc2616.txt"></a>.
      *
      * <p>This method does not need to be either safe or idempotent.
      * Operations that <code>doPut</code> performs can have side
      * effects for which the user can be held accountable. When using
      * this method, it may be useful to save a copy of the
      * affected URL in temporary storage.
      *
      * <p>If the HTTP PUT request is incorrectly formatted,
      * <code>doPut</code> returns an HTTP "Bad Request" message.
      *
      *
      * @param req	the {@link HttpServletRequest} object that
      *			contains the request the client made of
      *			the servlet
      *
      * @param resp	the {@link HttpServletResponse} object that
      *			contains the response the servlet returns
      *			to the client
      *
      * @exception IOException	if an input or output error occurs
      *				while the servlet is handling the
      *				PUT request
      *
      * @exception ServletException	if the request for the PUT
      *					cannot be handled
      *
      */
   
     protected void doPut(HttpServletRequest req, HttpServletResponse resp)
 	throws ServletException, IOException
     {
 	String protocol = req.getProtocol();
 	String msg = lStrings.getString("http.method_put_not_supported");
 	if (protocol.endsWith("1.1")) {
 	    resp.sendError(HttpServletResponse.SC_METHOD_NOT_ALLOWED, msg);
 	} else {
 	    resp.sendError(HttpServletResponse.SC_BAD_REQUEST, msg);
 	}
     }
 
 
 
 
     /**
      * 
      * Called by the server (via the <code>service</code> method)
      * to allow a servlet to handle a DELETE request.
      *
      * The DELETE operation allows a client to remove a document
      * or Web page from the server.
      * 
      * <p>This method does not need to be either safe
      * or idempotent. Operations requested through
      * DELETE can have side effects for which users
      * can be held accountable. When using
      * this method, it may be useful to save a copy of the
      * affected URL in temporary storage.
      *
      * <p>If the HTTP DELETE request is incorrectly formatted,
      * <code>doDelete</code> returns an HTTP "Bad Request"
      * message.
      *
      *
      * @param req	the {@link HttpServletRequest} object that
      *			contains the request the client made of
      *			the servlet
      *
      *
      * @param resp	the {@link HttpServletResponse} object that
      *			contains the response the servlet returns
      *			to the client				
      *
      *
      * @exception IOException	if an input or output error occurs
      *				while the servlet is handling the
      *				DELETE request
      *
      * @exception ServletException	if the request for the
      *					DELETE cannot be handled
      *
      */
      
     protected void doDelete(HttpServletRequest req,
 			    HttpServletResponse resp)
 	throws ServletException, IOException
     {
 	String protocol = req.getProtocol();
 	String msg = lStrings.getString("http.method_delete_not_supported");
 	if (protocol.endsWith("1.1")) {
 	    resp.sendError(HttpServletResponse.SC_METHOD_NOT_ALLOWED, msg);
 	} else {
 	    resp.sendError(HttpServletResponse.SC_BAD_REQUEST, msg);
 	}
     }
     
 
     private static Method[] getAllDeclaredMethods(Class c) {
 
         if (c.equals(javax.servlet.http.HttpServlet.class)) {
             return null;
         }
 
         Method[] parentMethods = getAllDeclaredMethods(c.getSuperclass());
         Method[] thisMethods = c.getDeclaredMethods();
 	
         if ((parentMethods != null) && (parentMethods.length > 0)) {
             Method[] allMethods =
                 new Method[parentMethods.length + thisMethods.length];
 	    System.arraycopy(parentMethods, 0, allMethods, 0,
                              parentMethods.length);
 	    System.arraycopy(thisMethods, 0, allMethods, parentMethods.length,
                              thisMethods.length);
 
 	    thisMethods = allMethods;
 	}
 
 	return thisMethods;
     }
 
 
     /**
      * Called by the server (via the <code>service</code> method)
      * to allow a servlet to handle a OPTIONS request.
      *
      * The OPTIONS request determines which HTTP methods 
      * the server supports and
      * returns an appropriate header. For example, if a servlet
      * overrides <code>doGet</code>, this method returns the
      * following header:
      *
      * <p><code>Allow: GET, HEAD, TRACE, OPTIONS</code>
      *
      * <p>There's no need to override this method unless the
      * servlet implements new HTTP methods, beyond those 
      * implemented by HTTP 1.1.
      *
      * @param req	the {@link HttpServletRequest} object that
      *			contains the request the client made of
      *			the servlet
      *
      *
      * @param resp	the {@link HttpServletResponse} object that
      *			contains the response the servlet returns
      *			to the client				
      *
      *
      * @exception IOException	if an input or output error occurs
      *				while the servlet is handling the
      *				OPTIONS request
      *
      * @exception ServletException	if the request for the
      *					OPTIONS cannot be handled
      *
      */
          
     protected void doOptions(HttpServletRequest req, HttpServletResponse resp)
 	throws ServletException, IOException
     {
 	Method[] methods = getAllDeclaredMethods(this.getClass());
 	
 	boolean ALLOW_GET = false;
 	boolean ALLOW_HEAD = false;
 	boolean ALLOW_POST = false;
 	boolean ALLOW_PUT = false;
 	boolean ALLOW_DELETE = false;
 	boolean ALLOW_TRACE = true;
 	boolean ALLOW_OPTIONS = true;
 	
 	for (int i=0; i<methods.length; i++) {
 	    Method m = methods[i];
 	    
 	    if (m.getName().equals("doGet")) {
 		ALLOW_GET = true;
 		ALLOW_HEAD = true;
 	    }
 	    if (m.getName().equals("doPost")) 
 		ALLOW_POST = true;
 	    if (m.getName().equals("doPut"))
 		ALLOW_PUT = true;
 	    if (m.getName().equals("doDelete"))
 		ALLOW_DELETE = true;
 	    
 	}
 	
 	String allow = null;
 	if (ALLOW_GET)
 	    if (allow==null) allow=METHOD_GET;
 	if (ALLOW_HEAD)
 	    if (allow==null) allow=METHOD_HEAD;
 	    else allow += ", " + METHOD_HEAD;
 	if (ALLOW_POST)
 	    if (allow==null) allow=METHOD_POST;
 	    else allow += ", " + METHOD_POST;
 	if (ALLOW_PUT)
 	    if (allow==null) allow=METHOD_PUT;
 	    else allow += ", " + METHOD_PUT;
 	if (ALLOW_DELETE)
 	    if (allow==null) allow=METHOD_DELETE;
 	    else allow += ", " + METHOD_DELETE;
 	if (ALLOW_TRACE)
 	    if (allow==null) allow=METHOD_TRACE;
 	    else allow += ", " + METHOD_TRACE;
 	if (ALLOW_OPTIONS)
 	    if (allow==null) allow=METHOD_OPTIONS;
 	    else allow += ", " + METHOD_OPTIONS;
 	
 	resp.setHeader("Allow", allow);
     }
     
     
     
     
     /**
      * Called by the server (via the <code>service</code> method)
      * to allow a servlet to handle a TRACE request.
      *
      * A TRACE returns the headers sent with the TRACE
      * request to the client, so that they can be used in
      * debugging. There's no need to override this method. 
      *
      *
      *
      * @param req	the {@link HttpServletRequest} object that
      *			contains the request the client made of
      *			the servlet
      *
      *
      * @param resp	the {@link HttpServletResponse} object that
      *			contains the response the servlet returns
      *			to the client				
      *
      *
      * @exception IOException	if an input or output error occurs
      *				while the servlet is handling the
      *				TRACE request
      *
      * @exception ServletException	if the request for the
      *					TRACE cannot be handled
      *
      */
 
     protected void doTrace(HttpServletRequest req, HttpServletResponse resp) 
 	throws ServletException, IOException
     {
 	
 	int responseLength;
 	
 	String CRLF = "\r\n";
 	String responseString = "TRACE "+ req.getRequestURI()+
 	    " " + req.getProtocol();
 	
 	Enumeration reqHeaderEnum = req.getHeaderNames();
 	
 	while( reqHeaderEnum.hasMoreElements() ) {
 	    String headerName = (String)reqHeaderEnum.nextElement();
 	    responseString += CRLF + headerName + ": " +
 		req.getHeader(headerName); 
 	}
 	
 	responseString += CRLF;
 	
 	responseLength = responseString.length();
 	
 	resp.setContentType("message/http");
 	resp.setContentLength(responseLength);
 	ServletOutputStream out = resp.getOutputStream();
 	out.print(responseString);	
 	out.close();
 	return;
     }		
 
 
 
 
 
     /**
      *
      * Receives standard HTTP requests from the public
      * <code>service</code> method and dispatches
      * them to the <code>do</code><i>XXX</i> methods defined in 
      * this class. This method is an HTTP-specific version of the 
      * {@link javax.servlet.Servlet#service} method. There's no
      * need to override this method.
      *
      *
      *
      * @param req	the {@link HttpServletRequest} object that
      *			contains the request the client made of
      *			the servlet
      *
      *
      * @param resp	the {@link HttpServletResponse} object that
      *			contains the response the servlet returns
      *			to the client				
      *
      *
      * @exception IOException	if an input or output error occurs
      *				while the servlet is handling the
      *				HTTP request
      *
      * @exception ServletException	if the HTTP request
      *					cannot be handled
      * 
      * @see 				javax.servlet.Servlet#service
      *
      */
 
     protected void service(HttpServletRequest req, HttpServletResponse resp)
 	throws ServletException, IOException
     {
 	String method = req.getMethod();
 
 	if (method.equals(METHOD_GET)) {
 	    long lastModified = getLastModified(req);
 	    if (lastModified == -1) {
 		// servlet doesn't support if-modified-since, no reason
 		// to go through further expensive logic
 		doGet(req, resp);
 	    } else {
 		long ifModifiedSince = req.getDateHeader(HEADER_IFMODSINCE);
 		if (ifModifiedSince < (lastModified / 1000 * 1000)) {
 		    // If the servlet mod time is later, call doGet()
                     // Round down to the nearest second for a proper compare
                     // A ifModifiedSince of -1 will always be less
 		    maybeSetLastModified(resp, lastModified);
 		    doGet(req, resp);
 		} else {
 		    resp.setStatus(HttpServletResponse.SC_NOT_MODIFIED);
 		}
 	    }
 
 	} else if (method.equals(METHOD_HEAD)) {
 	    long lastModified = getLastModified(req);
 	    maybeSetLastModified(resp, lastModified);
 	    doHead(req, resp);
 
 	} else if (method.equals(METHOD_POST)) {
 	    doPost(req, resp);
 	    
 	} else if (method.equals(METHOD_PUT)) {
 	    doPut(req, resp);	
 	    
 	} else if (method.equals(METHOD_DELETE)) {
 	    doDelete(req, resp);
 	    
 	} else if (method.equals(METHOD_OPTIONS)) {
 	    doOptions(req,resp);
 	    
 	} else if (method.equals(METHOD_TRACE)) {
 	    doTrace(req,resp);
 	    
 	} else {
 	    //
 	    // Note that this means NO servlet supports whatever
 	    // method was requested, anywhere on this server.
 	    //
 
 	    String errMsg = lStrings.getString("http.method_not_implemented");
 	    Object[] errArgs = new Object[1];
 	    errArgs[0] = method;
 	    errMsg = MessageFormat.format(errMsg, errArgs);
 	    
 	    resp.sendError(HttpServletResponse.SC_NOT_IMPLEMENTED, errMsg);
 	}
     }
     
 
 
 
 
     /*
      * Sets the Last-Modified entity header field, if it has not
      * already been set and if the value is meaningful.  Called before
      * doGet, to ensure that headers are set before response data is
      * written.  A subclass might have set this header already, so we
      * check.
      */
 
     private void maybeSetLastModified(HttpServletResponse resp,
 				      long lastModified) {
 	if (resp.containsHeader(HEADER_LASTMOD))
 	    return;
 	if (lastModified >= 0)
 	    resp.setDateHeader(HEADER_LASTMOD, lastModified);
     }
    
    
    
     
     /**
      *
      * Dispatches client requests to the protected
      * <code>service</code> method. There's no need to
      * override this method.
      *
      * 
      * @param req	the {@link HttpServletRequest} object that
      *			contains the request the client made of
      *			the servlet
      *
      *
      * @param res	the {@link HttpServletResponse} object that
      *			contains the response the servlet returns
      *			to the client				
      *
      *
      * @exception IOException	if an input or output error occurs
      *				while the servlet is handling the
      *				HTTP request
      *
      * @exception ServletException	if the HTTP request cannot
      *					be handled
      *
      * 
      * @see javax.servlet.Servlet#service
      *
      */
 
     public void service(ServletRequest req, ServletResponse res)
 	throws ServletException, IOException
     {
 	HttpServletRequest	request;
 	HttpServletResponse	response;
 	
 	try {
 	    request = (HttpServletRequest) req;
 	    response = (HttpServletResponse) res;
 	} catch (ClassCastException e) {
 	    throw new ServletException("non-HTTP request or response");
 	}
 	service(request, response);
     }
 }
 
 
 
 
 /*
  * A response that includes no body, for use in (dumb) "HEAD" support.
  * This just swallows that body, counting the bytes in order to set
  * the content length appropriately.  All other methods delegate directly
  * to the HTTP Servlet Response object used to construct this one.
  */
 // file private
 class NoBodyResponse extends HttpServletResponseWrapper {
     private NoBodyOutputStream		noBody;
     private PrintWriter			writer;
     private boolean			didSetContentLength;
 
     // file private
     NoBodyResponse(HttpServletResponse r) {
         super(r);
 	noBody = new NoBodyOutputStream();
     }
 
     // file private
     void setContentLength() {
 	if (!didSetContentLength)
 	  super.setContentLength(noBody.getContentLength());
     }
 
 
     // SERVLET RESPONSE interface methods
 
     public void setContentLength(int len) {
 	super.setContentLength(len);
 	didSetContentLength = true;
     }
 
     public ServletOutputStream getOutputStream() throws IOException
       { return noBody; }
 
     public PrintWriter getWriter() throws UnsupportedEncodingException
     {
 	if (writer == null) {
 	    OutputStreamWriter	w;
 
 	    w = new OutputStreamWriter(noBody, getCharacterEncoding());
 	    writer = new PrintWriter(w);
 	}
 	return writer;
     }
 
 }
 
 
 
 
 
 
 
 /*
  * Servlet output stream that gobbles up all its data.
  */
  
 // file private
 class NoBodyOutputStream extends ServletOutputStream {
 
     private static final String LSTRING_FILE =
 	"javax.servlet.http.LocalStrings";
     private static ResourceBundle lStrings =
 	ResourceBundle.getBundle(LSTRING_FILE);
 
     private int		contentLength = 0;
 
     // file private
     NoBodyOutputStream() {}
 
     // file private
     int getContentLength() {
 	return contentLength;
     }
 
     public void write(int b) {
 	contentLength++;
     }
 
     public void write(byte buf[], int offset, int len)
 	throws IOException
     {
 	if (len >= 0) {
 	    contentLength += len;
 	} else {
 	    // XXX
 	    // isn't this really an IllegalArgumentException?
 	    
 	    String msg = lStrings.getString("err.io.negativelength");
 	    throw new IOException("negative length");
 	}
     }
 }