Java tutorial
/* * Copyright 2008 Google Inc. * * 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.dingziran.effective.client; import com.dingziran.effective.client.MainMenuTreeViewModel.Category; import com.dingziran.effective.client.resources.ShowcaseResources; import com.dingziran.effective.shared.Factory; import com.google.gwt.core.client.EntryPoint; import com.google.gwt.core.client.GWT; import com.google.gwt.core.client.prefetch.Prefetcher; import com.google.gwt.dom.client.Document; import com.google.gwt.dom.client.HeadElement; import com.google.gwt.dom.client.LinkElement; import com.google.gwt.event.logical.shared.OpenEvent; import com.google.gwt.event.logical.shared.OpenHandler; import com.google.gwt.event.logical.shared.ValueChangeEvent; import com.google.gwt.event.logical.shared.ValueChangeHandler; import com.google.gwt.event.shared.SimpleEventBus; import com.google.gwt.i18n.client.LocaleInfo; import com.google.gwt.safehtml.shared.SafeHtmlBuilder; import com.google.gwt.safehtml.shared.SafeHtmlUtils; import com.google.gwt.user.cellview.client.CellTree; import com.google.gwt.user.cellview.client.TreeNode; import com.google.gwt.user.client.History; import com.google.gwt.user.client.Window; import com.google.gwt.user.client.ui.HTML; import com.google.gwt.user.client.ui.RootLayoutPanel; import com.google.gwt.user.client.ui.RootPanel; import com.google.gwt.view.client.SelectionChangeEvent; import com.google.gwt.view.client.SingleSelectionModel; import com.google.web.bindery.requestfactory.shared.Receiver; import java.util.ArrayList; import java.util.List; import java.util.Set; /** * Entry point classes define <code>onModuleLoad()</code>. */ public class Showcase implements EntryPoint { /** * The static images used throughout the Showcase. */ public static final ShowcaseResources images = GWT.create(ShowcaseResources.class); /** * The name of the style theme used in showcase. */ public static final String THEME = "clean"; /** * Get the token for a given content widget. * * @return the content widget token. */ public static String getContentWidgetToken(ContentWidget content) { return getContentWidgetToken(content.getClass()); } /** * Get the token for a given content widget. * * @return the content widget token. */ public static <C extends ContentWidget> String getContentWidgetToken(Class<C> cwClass) { String className = cwClass.getName(); className = className.substring(className.lastIndexOf('.') + 1); return "!" + className; } /** * The main application shell. */ private ShowcaseShell shell; static Factory factory; public static Factory getFactory() { return factory; } static SimpleEventBus eventBus; public static SimpleEventBus getEventBus() { return eventBus; } /** * This is the entry point method. */ public void onModuleLoad() { factory = GWT.create(Factory.class); eventBus = new SimpleEventBus(); factory.initialize(eventBus); // Inject global styles. injectThemeStyleSheet(); images.css().ensureInjected(); // Initialize the constants. ShowcaseConstants constants = GWT.create(ShowcaseConstants.class); // Create the application shell. final SingleSelectionModel<ContentWidget> selectionModel = new SingleSelectionModel<ContentWidget>(); final MainMenuTreeViewModel treeModel = new MainMenuTreeViewModel(constants, selectionModel); Set<ContentWidget> contentWidgets = treeModel.getAllContentWidgets(); shell = new ShowcaseShell(treeModel); RootLayoutPanel.get().add(shell); final CellTree mainMenu = shell.getMainMenu(); /* // Prefetch examples when opening the Category tree nodes. final List<Category> prefetched = new ArrayList<Category>(); mainMenu.addOpenHandler(new OpenHandler<TreeNode>() { public void onOpen(OpenEvent<TreeNode> event) { Object value = event.getTarget().getValue(); if (!(value instanceof Category)) { return; } Category category = (Category) value; if (!prefetched.contains(category)) { prefetched.add(category); Prefetcher.prefetch(category.getSplitPoints()); } } }); // Always prefetch. Prefetcher.start(); */ // Change the history token when a main menu item is selected. selectionModel.addSelectionChangeHandler(new SelectionChangeEvent.Handler() { public void onSelectionChange(SelectionChangeEvent event) { ContentWidget selected = selectionModel.getSelectedObject(); if (selected != null) { History.newItem(getContentWidgetToken(selected), true); } } }); // Setup a history handler to reselect the associate menu item. final ValueChangeHandler<String> historyHandler = new ValueChangeHandler<String>() { public void onValueChange(ValueChangeEvent<String> event) { // Get the content widget associated with the history token. ContentWidget contentWidget = treeModel.getContentWidgetForToken(event.getValue()); if (contentWidget == null) { return; } // Expand the tree node associated with the content. Category category = treeModel.getCategoryForContentWidget(contentWidget); TreeNode node = mainMenu.getRootTreeNode(); int childCount = node.getChildCount(); for (int i = 0; i < childCount; i++) { if (node.getChildValue(i) == category) { node.setChildOpen(i, true, true); break; } } // Select the node in the tree. selectionModel.setSelected(contentWidget, true); // Display the content widget. displayContentWidget(contentWidget); } }; History.addValueChangeHandler(historyHandler); // Show the initial example. if (History.getToken().length() > 0) { History.fireCurrentHistoryState(); } else { // Use the first token available. TreeNode root = mainMenu.getRootTreeNode(); TreeNode category = root.setChildOpen(0, true); ContentWidget content = (ContentWidget) category.getChildValue(0); selectionModel.setSelected(content, true); } // Generate a site map. createSiteMap(contentWidgets); } /** * Create a hidden site map for crawlability. * * @param contentWidgets the {@link ContentWidget}s used in Showcase */ private void createSiteMap(Set<ContentWidget> contentWidgets) { SafeHtmlBuilder sb = new SafeHtmlBuilder(); for (ContentWidget cw : contentWidgets) { String token = getContentWidgetToken(cw); sb.append(SafeHtmlUtils.fromTrustedString("<a href=\"#" + token + "\">" + token + "</a>")); } // Add the site map to the page. HTML siteMap = new HTML(sb.toSafeHtml()); siteMap.setVisible(false); RootPanel.get().add(siteMap, 0, 0); } /** * Set the content to the {@link ContentWidget}. * * @param content the {@link ContentWidget} to display */ private void displayContentWidget(ContentWidget content) { if (content == null) { return; } shell.setContent(content); Window.setTitle("Showcase of Features: " + content.getName()); } /** * Convenience method for getting the document's head element. * * @return the document's head element */ private native HeadElement getHeadElement() /*-{ return $doc.getElementsByTagName("head")[0]; }-*/; /** * Inject the GWT theme style sheet based on the RTL direction of the current * locale. */ private void injectThemeStyleSheet() { // Choose the name style sheet based on the locale. String styleSheet = "gwt/" + THEME + "/" + THEME; styleSheet += LocaleInfo.getCurrentLocale().isRTL() ? "_rtl.css" : ".css"; // Load the GWT theme style sheet String modulePath = GWT.getModuleBaseURL(); LinkElement linkElem = Document.get().createLinkElement(); linkElem.setRel("stylesheet"); linkElem.setType("text/css"); linkElem.setHref(modulePath + styleSheet); getHeadElement().appendChild(linkElem); } }