vaadin-framework/server/src/main/java/com/vaadin/server/DefaultUIProvider.java

/*
 * Copyright 2000-2018 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.server;

import com.vaadin.ui.UI;

public class DefaultUIProvider extends UIProvider {

    @Override
    public Class<? extends UI> getUIClass(UIClassSelectionEvent event) {
        VaadinRequest request = event.getRequest();

        String uiClassName = request.getService().getDeploymentConfiguration()
                .getUIClassName();
        if (uiClassName != null) {
            ClassLoader classLoader = request.getService().getClassLoader();
            try {
                Class<? extends UI> uiClass = Class
                        .forName(uiClassName, true, classLoader)
                        .asSubclass(UI.class);

                return uiClass;
            } catch (ClassNotFoundException e) {
                throw new RuntimeException("Could not find UI class", e);
            }
        }

        return null;
    }
}