Allow specifying UIProvider using a servlet parameter (#9628)

WebContent/WEB-INF/web.xml

@@ -30,6 +30,18 @@
 			<param-value>com.vaadin.tests.components.label.MarginsInLabels</param-value>
 		</init-param>
 	</servlet>
+	<servlet>
+		<servlet-name>UI provider app</servlet-name>
+		<servlet-class>com.vaadin.server.VaadinServlet</servlet-class>
+		<init-param>
+			<param-name>UIProvider</param-name>
+			<param-value>com.vaadin.tests.applicationservlet.InitParamUIProvider</param-value>
+		</init-param>
+		<init-param>
+			<param-name>UI</param-name>
+			<param-value>com.vaadin.tests.VerifyAssertionsEnabled</param-value>
+		</init-param>
+	</servlet>
 
 	<context-param>
 		<param-name>resourceCacheTime</param-name>
@@ -60,6 +72,11 @@
 		<url-pattern>/embed2/*</url-pattern>
 	</servlet-mapping>
 	
+	<servlet-mapping>
+		<servlet-name>UI provider app</servlet-name>
+		<url-pattern>/uiprovider/*</url-pattern>
+	</servlet-mapping>
+	
 	<servlet-mapping>
 		<servlet-name>VaadinApplicationRunner</servlet-name>
 		<url-pattern>/run/*</url-pattern>

server/src/com/vaadin/server/Constants.java

@@ -63,6 +63,7 @@ public interface Constants {
     static final String SERVLET_PARAMETER_RESOURCE_CACHE_TIME = "resourceCacheTime";
     static final String SERVLET_PARAMETER_HEARTBEAT_RATE = "heartbeatRate";
     static final String SERVLET_PARAMETER_CLOSE_IDLE_UIS = "closeIdleUIs";
+    static final String SERVLET_PARAMETER_UI_PROVIDER = "UIProvider";
 
     // Configurable parameter names
     static final String PARAMETER_VAADIN_RESOURCES = "Resources";

server/src/com/vaadin/server/ServletPortletHelper.java

@@ -119,18 +119,48 @@ class ServletPortletHelper implements Serializable {
 
     public static void initDefaultUIProvider(VaadinSession session,
             VaadinService vaadinService) throws ServiceException {
-        Properties initParameters = vaadinService.getDeploymentConfiguration()
-                .getInitParameters();
-        String uiProperty = initParameters
-                .getProperty(VaadinSession.UI_PARAMETER);
-        if (uiProperty == null) {
-            uiProperty = initParameters.getProperty(VaadinSession.UI_PARAMETER
-                    .toLowerCase());
-        }
+        String uiProperty = vaadinService.getDeploymentConfiguration()
+                .getApplicationOrSystemProperty(VaadinSession.UI_PARAMETER,
+                        null);
+
+        // Add provider for UI parameter first to give it lower priority
+        // (providers are FILO)
         if (uiProperty != null) {
             verifyUIClass(uiProperty, vaadinService.getClassLoader());
             vaadinService.addUIProvider(session, new DefaultUIProvider());
         }
+
+        String uiProviderProperty = vaadinService.getDeploymentConfiguration()
+                .getApplicationOrSystemProperty(
+                        Constants.SERVLET_PARAMETER_UI_PROVIDER, null);
+        // Then add custom UI provider if defined
+        if (uiProviderProperty != null) {
+            UIProvider uiProvider = getUIProvider(uiProviderProperty,
+                    vaadinService.getClassLoader());
+            vaadinService.addUIProvider(session, uiProvider);
+        }
+    }
+
+    private static UIProvider getUIProvider(String uiProviderProperty,
+            ClassLoader classLoader) throws ServiceException {
+        try {
+            Class<?> providerClass = classLoader.loadClass(uiProviderProperty);
+            Class<? extends UIProvider> subclass = providerClass
+                    .asSubclass(UIProvider.class);
+            return subclass.newInstance();
+        } catch (ClassNotFoundException e) {
+            throw new ServiceException("Could not load UIProvider class "
+                    + uiProviderProperty, e);
+        } catch (ClassCastException e) {
+            throw new ServiceException("UIProvider class " + uiProviderProperty
+                    + " does not extend UIProvider", e);
+        } catch (InstantiationException e) {
+            throw new ServiceException("Could not instantiate UIProvider "
+                    + uiProviderProperty, e);
+        } catch (IllegalAccessException e) {
+            throw new ServiceException("Could not instantiate UIProvider "
+                    + uiProviderProperty, e);
+        }
     }
 
     public static void checkUiProviders(VaadinSession session,

uitest/src/com/vaadin/tests/applicationservlet/InitParamUIProvider.java

@@ -0,0 +1,36 @@
+/*
+ * Copyright 2011 Vaadin Ltd.
+ * 
+ * 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 com.vaadin.tests.applicationservlet;
+
+import com.vaadin.server.UIProvider;
+import com.vaadin.server.VaadinRequest;
+import com.vaadin.tests.components.javascriptcomponent.BasicJavaScriptComponent;
+import com.vaadin.ui.UI;
+
+public class InitParamUIProvider extends UIProvider {
+
+    @Override
+    public Class<? extends UI> getUIClass(VaadinRequest request) {
+        String pathInfo = request.getRequestPathInfo();
+        if ("/test".equals(pathInfo)) {
+            return BasicJavaScriptComponent.class;
+        } else {
+            return null;
+        }
+    }
+
+}

uitest/src/com/vaadin/tests/applicationservlet/UIProviderInitParameter.html

@@ -0,0 +1,39 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
+<head profile="http://selenium-ide.openqa.org/profiles/test-case">
+<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
+<link rel="selenium.base" href="" />
+<title>New Test</title>
+</head>
+<body>
+<table cellpadding="1" cellspacing="1" border="1">
+<thead>
+<tr><td rowspan="1" colspan="3">New Test</td></tr>
+</thead><tbody>
+<tr>
+	<td>open</td>
+	<td>/uiprovider</td>
+	<td></td>
+</tr>
+<!--Test that UI parameter is used by default-->
+<tr>
+	<td>assertText</td>
+	<td>vaadin=uiprovider::/VVerticalLayout[0]/VOrderedLayout$Slot[0]/VLabel[0]</td>
+	<td>Tests whether the testing server is run with assertions enabled.</td>
+</tr>
+<!--Test that UIProvider parameter is more important than UI parameter-->
+<tr>
+	<td>open</td>
+	<td>/uiprovider/test</td>
+	<td></td>
+</tr>
+<tr>
+	<td>assertText</td>
+	<td>vaadin=uiprovider::/VVerticalLayout[0]/VOrderedLayout$Slot[0]/VLabel[0]</td>
+	<td>Test for basic JavaScript component functionality.</td>
+</tr>
+
+</tbody></table>
+</body>
+</html>