Add RootProvider for Root selection without custom Application (#8159)

5 files changed, 141 insertions, 46 deletions

diff --git a/server/src/com/vaadin/Application.java b/server/src/com/vaadin/Application.java
index b120c8455a..d2924eb716 100644
--- a/server/src/com/vaadin/Application.java
+++ b/server/src/com/vaadin/Application.java
@@ -32,6 +32,7 @@ import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Hashtable;
 import java.util.LinkedList;
+import java.util.List;
 import java.util.Locale;
 import java.util.Map;
 import java.util.Map.Entry;
@@ -56,6 +57,7 @@ import com.vaadin.terminal.ApplicationResource;
 import com.vaadin.terminal.CombinedRequest;
 import com.vaadin.terminal.DeploymentConfiguration;
 import com.vaadin.terminal.RequestHandler;
+import com.vaadin.terminal.RootProvider;
 import com.vaadin.terminal.Terminal;
 import com.vaadin.terminal.VariableOwner;
 import com.vaadin.terminal.WrappedRequest;
@@ -503,6 +505,8 @@ public class Application implements Terminal.ErrorListener, Serializable {
      */
     private Set<Integer> initedRoots = new HashSet<Integer>();
 
+    private List<RootProvider> rootProviders = new LinkedList<RootProvider>();
+
     /**
      * Gets the user of the application.
      * 
@@ -1873,55 +1877,21 @@ public class Application implements Terminal.ErrorListener, Serializable {
      */
     protected Root getRoot(WrappedRequest request)
             throws RootRequiresMoreInformationException {
-        String rootClassName = getRootClassName(request);
-        try {
-            ClassLoader classLoader = request.getDeploymentConfiguration()
-                    .getClassLoader();
-            if (classLoader == null) {
-                classLoader = getClass().getClassLoader();
-            }
-            Class<? extends Root> rootClass = Class.forName(rootClassName,
-                    true, classLoader).asSubclass(Root.class);
-            try {
-                Root root = rootClass.newInstance();
-                return root;
-            } catch (Exception e) {
-                throw new RuntimeException("Could not instantiate root class "
-                        + rootClassName, e);
+
+        // Iterate in reverse order - test check newest provider first
+        for (int i = rootProviders.size() - 1; i >= 0; i--) {
+            RootProvider provider = rootProviders.get(i);
+
+            Class<? extends Root> rootClass = provider.getRootClass(this,
+                    request);
+
+            if (rootClass != null) {
+                return provider.instantiateRoot(this, rootClass, request);
             }
-        } catch (ClassNotFoundException e) {
-            throw new RuntimeException("Could not load root class "
-                    + rootClassName, e);
         }
-    }
 
-    /**
-     * Provides the name of the <code>Root</code> class that should be used for
-     * a request. The class must have an accessible no-args constructor.
-     * <p>
-     * The default implementation uses the {@value #ROOT_PARAMETER} parameter
-     * from web.xml.
-     * </p>
-     * <p>
-     * This method is mainly used by the default implementation of
-     * {@link #getRoot(WrappedRequest)}. If you override that method with your
-     * own functionality, the results of this method might not be used.
-     * </p>
-     * 
-     * @param request
-     *            the request for which a new root is required
-     * @return the name of the root class to use
-     * 
-     * @since 7.0
-     */
-    protected String getRootClassName(WrappedRequest request) {
-        Object rootClassNameObj = getProperties().get(ROOT_PARAMETER);
-        if (rootClassNameObj instanceof String) {
-            return (String) rootClassNameObj;
-        } else {
-            throw new RuntimeException("No " + ROOT_PARAMETER
-                    + " defined in web.xml");
-        }
+        throw new RuntimeException(
+                "No root providers available or providers are not able to find root instance");
     }
 
     /**
@@ -2169,6 +2139,14 @@ public class Application implements Terminal.ErrorListener, Serializable {
         return configuration.isProductionMode();
     }
 
+    public void addRootProvider(RootProvider rootProvider) {
+        rootProviders.add(rootProvider);
+    }
+
+    public void removeRootProvider(RootProvider rootProvider) {
+        rootProviders.remove(rootProvider);
+    }
+
     /**
      * Finds the {@link Root} to which a particular request belongs. If the
      * request originates from an existing Root, that root is returned. In other
diff --git a/server/src/com/vaadin/terminal/AbstractRootProvider.java b/server/src/com/vaadin/terminal/AbstractRootProvider.java
new file mode 100644
index 0000000000..0b63003440
--- /dev/null
+++ b/server/src/com/vaadin/terminal/AbstractRootProvider.java
@@ -0,0 +1,35 @@
+/*

+ * 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.terminal;

+

+import com.vaadin.Application;

+import com.vaadin.ui.Root;

+

+public abstract class AbstractRootProvider implements RootProvider {

+

+    @Override

+    public Root instantiateRoot(Application application,

+            Class<? extends Root> type, WrappedRequest request) {

+        try {

+            return type.newInstance();

+        } catch (InstantiationException e) {

+            throw new RuntimeException("Could not instantiate root class", e);

+        } catch (IllegalAccessException e) {

+            throw new RuntimeException("Could not access root class", e);

+        }

+    }

+}

diff --git a/server/src/com/vaadin/terminal/DefaultRootProvider.java b/server/src/com/vaadin/terminal/DefaultRootProvider.java
new file mode 100644
index 0000000000..cbf8c98828
--- /dev/null
+++ b/server/src/com/vaadin/terminal/DefaultRootProvider.java
@@ -0,0 +1,51 @@
+/*

+ * 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.terminal;

+

+import com.vaadin.Application;

+import com.vaadin.RootRequiresMoreInformationException;

+import com.vaadin.ui.Root;

+

+public class DefaultRootProvider extends AbstractRootProvider {

+

+    @Override

+    public Class<? extends Root> getRootClass(Application application,

+            WrappedRequest request) throws RootRequiresMoreInformationException {

+        Object rootClassNameObj = application

+                .getProperty(Application.ROOT_PARAMETER);

+

+        if (rootClassNameObj instanceof String) {

+            String rootClassName = rootClassNameObj.toString();

+

+            ClassLoader classLoader = request.getDeploymentConfiguration()

+                    .getClassLoader();

+            if (classLoader == null) {

+                classLoader = getClass().getClassLoader();

+            }

+            try {

+                Class<? extends Root> rootClass = Class.forName(rootClassName,

+                        true, classLoader).asSubclass(Root.class);

+

+                return rootClass;

+            } catch (ClassNotFoundException e) {

+                throw new RuntimeException("Could not find root class", e);

+            }

+        }

+

+        return null;

+    }

+}

diff --git a/server/src/com/vaadin/terminal/RootProvider.java b/server/src/com/vaadin/terminal/RootProvider.java
new file mode 100644
index 0000000000..476cf1bd78
--- /dev/null
+++ b/server/src/com/vaadin/terminal/RootProvider.java
@@ -0,0 +1,29 @@
+/*

+ * 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.terminal;

+

+import com.vaadin.Application;

+import com.vaadin.RootRequiresMoreInformationException;

+import com.vaadin.ui.Root;

+

+public interface RootProvider {

+    public Class<? extends Root> getRootClass(Application application,

+            WrappedRequest request) throws RootRequiresMoreInformationException;

+

+    public Root instantiateRoot(Application application,

+            Class<? extends Root> type, WrappedRequest request);

+}

diff --git a/server/src/com/vaadin/terminal/gwt/server/ApplicationServlet.java b/server/src/com/vaadin/terminal/gwt/server/ApplicationServlet.java
index 06bc70872d..52885f3fbb 100644
--- a/server/src/com/vaadin/terminal/gwt/server/ApplicationServlet.java
+++ b/server/src/com/vaadin/terminal/gwt/server/ApplicationServlet.java
@@ -20,6 +20,7 @@ import javax.servlet.ServletException;
 import javax.servlet.http.HttpServletRequest;
 
 import com.vaadin.Application;
+import com.vaadin.terminal.DefaultRootProvider;
 import com.vaadin.terminal.gwt.server.ServletPortletHelper.ApplicationClassException;
 
 /**
@@ -69,6 +70,7 @@ public class ApplicationServlet extends AbstractApplicationServlet {
         // Creates a new application instance
         try {
             final Application application = getApplicationClass().newInstance();
+            application.addRootProvider(new DefaultRootProvider());
 
             return application;
         } catch (final IllegalAccessException e) {