// Copyright (c) 2000 Just Objects B.V. <just@justobjects.nl>// Distributable under LGPL license. See terms of license at gnu.org.package nl.justobjects.pushlet.util;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;/** * Servlet utilities. * * @author Just van den Broecke - Just Objects &copy; * @version $Id: Servlets.java,v 1.2 2007/11/23 21:10:17 justb Exp $ */public class Servlets {	/**	 * Get parameter; if not set or empty return null.	 */	public static String getParameter(HttpServletRequest aRequest, String aName) {		return getParameter(aRequest, aName, null);	}	/**	 * Get parameter; if not set or empty return specified default value.	 */	public static String getParameter(HttpServletRequest aRequest, String aName, String aDefault) {		String value = aRequest.getParameter(aName);		if (value == null || value.length() == 0) {			value = aDefault;		}		return value;	}	/**	 * Set HTTP headers to prevent caching.	 */	public static void setNoCacheHeaders(HttpServletResponse aResponse) {		// Set to expire far in the past.		aResponse.setHeader("Expires", "Sat, 6 May 1995 12:00:00 GMT");		// Set standard HTTP/1.1 no-cache headers.		aResponse.setHeader("Cache-Control", "no-store, no-cache, must-revalidate");		// Set IE extended HTTP/1.1 no-cache headers (use addHeader).		aResponse.addHeader("Cache-Control", "post-check=0, pre-check=0");		// Set standard HTTP/1.0 no-cache header.		aResponse.setHeader("Pragma", "no-cache");	}}/* * $Log: Servlets.java,v $ * Revision 1.2  2007/11/23 21:10:17  justb * add hooks for custom logging (you can override DefaultLogger in pushlet.properties) * * Revision 1.1  2004/09/20 22:01:40  justb * more changes for new protocol * * */