/* ======================================================================
   Parts Copyright 2006 University of Leeds, Oxford University, University of the Highlands and Islands.

   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.bodington.servlet;

import javax.servlet.http.*;
import java.text.SimpleDateFormat;
import java.util.TimeZone;
import java.util.Locale;
import java.util.Date;


/**
 * @author  bmb6jrm
 */
public class Response extends javax.servlet.http.HttpServletResponseWrapper
{
    
    HttpServletResponse wrapped_response;
    
    String html_body_class=null;

    /**
     * The date format we will use for creating date headers.
     * see setDateHeader method.
     * Locale US is one of many locales that would work OK.
     * It's only relevance is the spelling of day and month names
     */
    protected final SimpleDateFormat format =
        new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss zzz",Locale.US);

    
    /** Creates new Response */
    public Response( HttpServletResponse response )
    {
	super( response );
	wrapped_response = response;
        format.setTimeZone(TimeZone.getTimeZone("GMT"));
    }

    
    public void setHtmlBodyClass( String s )
    {
	html_body_class = s;
    }
    
    public String getHtmlBodyClass()
    {
	return html_body_class;
    }
    
    /** Set appropriate headers in response to prevent caching of the page. */
    public void disableCaching()
    {
	// for HTTP 1.1
	setHeader( "Cache-Control", "no-cache" );
	
	// for HTTP 1.0
	setHeader( "Pragma", "no-cache" );
    }

    
    /**
     * Add the specified date header to the specified value.
     * See setDateHeader for explanation of why this method is here.
     *
     * @param name Name of the header to set
     * @param value Date value to be set
     */
    public void addDateHeader(String name, long value)
    {
        if (wrapped_response.isCommitted())
            return;

        wrapped_response.addHeader(name, format.format(new Date(value)));

    }

    /**
     * Set the specified date header to the specified value.
     * This has been added into wrapper because the iPlanet
     * implementation of HttpServletResponse gets it wrong
     * by putting local time into the header although HTTP
     * requires GMT time.
     *
     * @param name Name of the header to set
     * @param value Date value to be set
     */
    public void setDateHeader(String name, long value)
    {
        if ( wrapped_response.isCommitted() )
            return;

        wrapped_response.setHeader(name, format.format(new Date(value)));
    }


}