vaadin-framework/client/src/main/java/com/vaadin/client/WidgetSet.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.client;

import java.util.logging.Level;
import java.util.logging.Logger;

import com.google.gwt.core.client.GWT;
import com.vaadin.client.metadata.BundleLoadCallback;
import com.vaadin.client.metadata.ConnectorBundleLoader;
import com.vaadin.client.metadata.NoDataException;
import com.vaadin.client.metadata.TypeData;
import com.vaadin.client.ui.UnknownComponentConnector;
import com.vaadin.client.ui.UnknownExtensionConnector;

public class WidgetSet {
    /**
     * Create an uninitialized connector that best matches given UIDL. The
     * connector must implement {@link ServerConnector}.
     *
     * @param tag
     *            connector type tag for the connector to create
     * @param conf
     *            the application configuration to use when creating the
     *            connector
     *
     * @return New uninitialized and unregistered connector that can paint given
     *         UIDL.
     */
    public ServerConnector createConnector(int tag,
            ApplicationConfiguration conf) {
        /*
         * Yes, this (including the generated code in WidgetMap) may look very
         * odd code, but due the nature of GWT, we cannot do this any cleaner.
         * Luckily this is mostly written by WidgetSetGenerator, here are just
         * some hacks. Extra instantiation code is needed if client side
         * connector has no "native" counterpart on client side.
         */
        Profiler.enter("WidgetSet.createConnector");

        Class<? extends ServerConnector> classType = resolveInheritedConnectorType(
                conf, tag);

        try {
            if (classType == null
                    || classType == UnknownComponentConnector.class
                    || classType == UnknownExtensionConnector.class) {
                String serverSideName = conf
                        .getUnknownServerClassNameByTag(tag);
                if (classType == UnknownExtensionConnector.class) {
                    // Display message in the console for non-visual connectors
                    getLogger().severe(UnknownComponentConnector
                            .createMessage(serverSideName));
                    return GWT.create(UnknownExtensionConnector.class);
                } else {
                    UnknownComponentConnector c = GWT
                            .create(UnknownComponentConnector.class);
                    // Set message to be shown in a widget for visual connectors
                    c.setServerSideClassName(serverSideName);
                    return c;
                }
            } else {
                /*
                 * let the auto generated code instantiate this type
                 */
                ServerConnector connector = (ServerConnector) TypeData
                        .getType(classType).createInstance();
                connector.setTag(tag);
                return connector;
            }
        } catch (NoDataException e) {
            throw new IllegalStateException(
                    "There is no information about " + classType
                            + ". Did you remember to compile the right widgetset?",
                    e);
        } finally {
            Profiler.leave("WidgetSet.createConnector");
        }
    }

    private Class<? extends ServerConnector> resolveInheritedConnectorType(
            ApplicationConfiguration conf, int tag) {
        Class<? extends ServerConnector> classType = null;
        Integer t = tag;
        do {
            classType = resolveConnectorType(t, conf);
            t = conf.getParentTag(t);
        } while (classType == null && t != null);
        return classType;
    }

    protected Class<? extends ServerConnector> resolveConnectorType(int tag,
            ApplicationConfiguration conf) {
        Class<? extends ServerConnector> connectorClass = conf
                .getConnectorClassByEncodedTag(tag);

        return connectorClass;
    }

    /**
     * Due its nature, GWT does not support dynamic classloading. To bypass this
     * limitation, widgetset must have function that returns Class by its fully
     * qualified name.
     *
     * @param tag
     * @param applicationConfiguration
     * @return
     */
    public void ensureConnectorLoaded(int tag, ApplicationConfiguration conf) {
        ConnectorBundleLoader loader = ConnectorBundleLoader.get();
        String bundleName = null;
        Integer t = tag;
        String serverSideClassName = "";
        do {
            serverSideClassName = conf.getServerSideClassNameForTag(t);
            bundleName = loader.getBundleForIdentifier(serverSideClassName);

            t = conf.getParentTag(t);
        } while (bundleName == null && t != null);

        if (bundleName != null && !loader.isBundleLoaded(bundleName)) {
            getLogger().info("Loading bundle " + bundleName
                    + " to be able to render server side class "
                    + serverSideClassName);
            ApplicationConfiguration.startDependencyLoading();
            loader.loadBundle(bundleName, new BundleLoadCallback() {
                @Override
                public void loaded() {
                    ApplicationConfiguration.endDependencyLoading();
                }

                @Override
                public void failed(Throwable reason) {
                    getLogger().log(Level.SEVERE, "Error loading bundle",
                            reason);
                    ApplicationConfiguration.endDependencyLoading();
                }
            });
        }
    }

    private static Logger getLogger() {
        return Logger.getLogger(WidgetSet.class.getName());
    }
}