fix: Load the portlet methods file from a jar resources

Uses portlet context and loads the portlet methods file from jar dependency resources instead of static bundle for Pluto 3.0 implementations except Liferay.

Fixes #191

vaadin-portlet/src/main/java/com/vaadin/flow/portal/VaadinLiferayPortlet.java

@@ -12,7 +12,7 @@
 
 /**
  * VaadinPortlet workarounds for Liferay versions 7.2.x and 7.3.x
- * 
+ *
  * Requires the implementing portlet to signal PortletHub dependency due to a Liferay bug.
  * Addresses inconsistent behaviour in injecting required Vaadin specific javascript.
  */
@@ -48,7 +48,7 @@ protected void doHeaders(RenderRequest request, RenderResponse response)
          * 1. The script tag will appear once per portlet
          * 2. Liferay partial page update breaks the page and causes Vaadin components to render blank
          *    *if* the browser has stale Vaadin related things from the previous page.
-         * 
+         *
          * In other words we probably need a surgical way to scrub stale Vaadin things from users browser
          * that only runs once, even if the script can be on the page multiple times. Alternatively we can
          * just detect the problem and force a hard reload.
@@ -61,6 +61,13 @@ protected void doHeaders(RenderRequest request, RenderResponse response)
         isPortlet3.set(true);
     }
 
+    @Override
+    protected String getStaticResourcesPath() {
+        return getService().getDeploymentConfiguration().getStringProperty(
+        PortletConstants.PORTLET_PARAMETER_STATIC_RESOURCES_MAPPING,
+        "/vaadin-portlet-static/");
+    }
+
     private boolean checkStaticResourcesConfiguration() {
         return getStaticResourcesPath().startsWith("/o/");
     }

vaadin-portlet/src/main/java/com/vaadin/flow/portal/VaadinPortlet.java

@@ -31,6 +31,7 @@
 import javax.portlet.HeaderResponse;
 import javax.portlet.PortalContext;
 import javax.portlet.PortletConfig;
+import javax.portlet.PortletContext;
 import javax.portlet.PortletException;
 import javax.portlet.PortletMode;
 import javax.portlet.PortletRequest;
@@ -245,18 +246,25 @@ public void renderHeaders(HeaderRequest request, HeaderResponse response)
 
     protected String getPortletScriptTag(RenderRequest request,
             String filePath) {
-        // static bundle or context path? 
+        // static bundle or context path?
         // latter is more lenient for old projects, former is less friendly to caching
+        // current implementation uses portlet context to load the portlet
+        // methods JS file and Liferay implementation uses static bundle
         String scriptSrc = getServerUrl(request) + getStaticResourcesPath()
                 + filePath;
         return "<script src=\"" + scriptSrc
                 + "\" type=\"text/javascript\"></script>";
     }
 
     protected String getStaticResourcesPath() {
-        return getService().getDeploymentConfiguration().getStringProperty(
-                PortletConstants.PORTLET_PARAMETER_STATIC_RESOURCES_MAPPING,
-                "/vaadin-portlet-static/");
+        PortletContext portletContext = getPortletContext();
+        if (portletContext != null) {
+            String contextPath = portletContext.getContextPath();
+            if (contextPath != null && !contextPath.isEmpty()) {
+                return contextPath + "/";
+            }
+        }
+        return "/";
     }
 
     private static String getServerUrl(RenderRequest req) {
@@ -597,7 +605,7 @@ private Logger getLogger() {
      * wants to be rendered in minimized state as well as other states, it
      * should override this method and return true.
      * </p>
-     * 
+     *
      * @return true is the portlet should be rendered in minimized state.
      *         Otherwise false.
      */