Index: src/main/java/org/displaytag/util/PortletRequestHelper.java
===================================================================
RCS file: src/main/java/org/displaytag/util/PortletRequestHelper.java
diff -N src/main/java/org/displaytag/util/PortletRequestHelper.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/main/java/org/displaytag/util/PortletRequestHelper.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,160 @@
+/**
+ * Licensed under the Artistic License; you may not use this file
+ * except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://displaytag.sourceforge.net/license.html
+ *
+ * THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+ * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ */
+package org.displaytag.util;
+
+import java.util.Map;
+
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import javax.servlet.jsp.PageContext;
+
+import javax.portlet.RenderResponse;
+import javax.portlet.PortletURL;
+
+/**
+ * RequestHelper which will work in Websphere Portal Server 4.2 (tested on 4.2.1, should work also in versions 4.x).
+ * Simply overrides the standard getHref() method to return an URL generated from calling
+ * portletRequest.getPortletURI(). Note you need to add the portletAPI:init tag before any displaytag tag to make this
+ * working.
+ * @author Fabrizio Giustina
+ * @version $Revision: 1.8 $ ($Author: fgiust $)
+ */
+public class PortletRequestHelper extends DefaultRequestHelper
+{
+
+    /**
+     * Action name added to the portlet URI.
+     */
+    private static final String REFRESH_ACTION = "refresh"; //$NON-NLS-1$
+
+    /**
+     * Page context attribute containing the portlet response object.
+     */
+    private static final String PORTLET_RESPONSE = "renderResponse"; //$NON-NLS-1$
+    private static final String PORTLET_REQUEST = "renderRequest"; //$NON-NLS-1$
+
+    /**
+     * jsp page context.
+     */
+    private PageContext pageContext;
+
+    /**
+     * Initialize a new WpsRequestHelper.
+     * @param context jsp page context
+     */
+    public PortletRequestHelper(PageContext context)
+    {
+        super((HttpServletRequest) context.getRequest(), (HttpServletResponse) context.getResponse());
+        this.pageContext = context;
+    }
+
+    /**
+     * @see org.displaytag.util.RequestHelper#getHref()
+     */
+    public Href getHref()
+    {
+        Href standardHref = super.getHref();
+
+        Map parameterMap = standardHref.getParameterMap();
+
+        Href portalHref = new Href(getRefreshUri());
+        portalHref.setParameterMap(parameterMap);
+
+        return portalHref;
+    }
+
+    /**
+     * Returns the url of a refresh uri (a simple action which forces the portlet to reload).
+     * @return String portletURI.toString()
+     */
+    private String getRefreshUri()
+    {
+        // get a base portlet URI from the portal without parameters
+        PortletURL portletURI = getPortletURL();
+
+        // must be unique to force refresh
+        // portletURL.addAction(REFRESH_ACTION + Math.random());
+
+        // it seems you need to add at least one parameter to the uri, if you want standard parameters to be catched...
+        portletURI.setParameter("init", "init"); //$NON-NLS-1$ //$NON-NLS-2$
+
+        return portletURI.toString();
+    }
+
+    /**
+     * Returns the PortletURI.
+     * @return PortletURI
+     */
+    public PortletURL getPortletURL()
+    {
+        RenderResponse renderResponse = getPortletResponse();
+
+        // initialize a new PortletURI
+        PortletURL portletURI = renderResponse.createRenderURL();
+
+        return portletURI;
+    }
+
+    /**
+     * Find the portlet response.
+     * @return a PortletResponse instance
+     */
+    protected RenderResponse getPortletResponse()
+    {
+
+        // esiste gi� nel pageContext la PortletResponse?
+        RenderResponse portletResponse = (RenderResponse) pageContext.getAttribute(PORTLET_RESPONSE);
+
+        // this will allow to obtain directly the portlet request using jetspeed internal APIs
+        // it's more "fail safe" than expecting the portlet response directly in the page context, but it's not
+        // officially supported. To compile these lines you also need jetspeed PORTAL classes in the classpath
+
+        // if (portletResponse == null)
+        // {
+        // portletResponse = (PortletResponse) ThreadAttributesManager
+        // .getAttribute("org.apache.jetspeed.portletcontainer.portlet.response");
+        // // sped up next calls
+        // pageContext.setAttribute(PORTLET_RESPONSE, portletResponse);
+        // }
+
+        if (portletResponse == null)
+        {
+            throw new RuntimePortalSupportException();
+        }
+
+        return portletResponse;
+    }
+
+    /**
+     * Simple runtime exception to inform the user about the missing <portletAPI:init> tag.
+     * @author Fabrizio Giustina
+     * @version $Revision: 1.8 $ ($Author: fgiust $)
+     */
+    public static class RuntimePortalSupportException extends RuntimeException
+    {
+
+        /**
+         * D1597A17A6.
+         */
+        private static final long serialVersionUID = 899149338534L;
+
+        /**
+         * Portlet response couldn't be found.
+         */
+        public RuntimePortalSupportException()
+        {
+            super("Portlet response couldn't be found. "
+                + "Be sure to have the portletAPI:init tag at the beginning of the page");
+        }
+
+    }
+}
Index: src/main/java/org/displaytag/util/PortletRequestHelperFactory.java
===================================================================
RCS file: src/main/java/org/displaytag/util/PortletRequestHelperFactory.java
diff -N src/main/java/org/displaytag/util/PortletRequestHelperFactory.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/main/java/org/displaytag/util/PortletRequestHelperFactory.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,40 @@
+/**
+ * Licensed under the Artistic License; you may not use this file
+ * except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://displaytag.sourceforge.net/license.html
+ *
+ * THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+ * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ */
+package org.displaytag.util;
+
+import javax.servlet.jsp.PageContext;
+
+
+/**
+ * RequestHelperFactory implementation that will work in Websphere Portal Server. (Tested on version 4.2).
+ * <p>
+ * In WPS links with "standard" parameters are handled, but if you turn on Portlet caching links which don't contain a
+ * PortletAction don't cause the cache to be refreshed (= the click is ignored).
+ * </p>
+ * <p>
+ * This factory implementation returns a standard {@link WpsRequestHelper}instance.
+ * </p>
+ * @author Fabrizio Giustina
+ * @version $Revision: 1.3 $ ($Author: fgiust $)
+ */
+public class PortletRequestHelperFactory implements RequestHelperFactory
+{
+
+    /**
+     * @see org.displaytag.util.RequestHelperFactory#getRequestHelperInstance(javax.servlet.jsp.PageContext)
+     */
+    public RequestHelper getRequestHelperInstance(PageContext pageContext)
+    {
+        return new PortletRequestHelper(pageContext);
+    }
+
+}