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/*
 * Copyright 2011 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.google.gwt.user.client.ui;

import com.google.gwt.core.client.Scheduler.ScheduledCommand;
import com.google.gwt.dom.builder.shared.HtmlElementBuilder;
import com.google.gwt.dom.client.Document;
import com.google.gwt.dom.client.Element;
import com.google.gwt.safehtml.shared.SafeHtml;
import com.google.gwt.safehtml.shared.SafeHtmlBuilder;

/**
 * EXPERIMENTAL and subject to change. Do not use this in production code.
 * 

* An {@link IsRenderable} version of {@link HTMLPanel}. This class is a stepping * in our transition to the Renderable strategy. Eventually this functionality * should be merged into {@link HTMLPanel}. * The only reason this class doesn't extend {@link HTMLPanel} is because it * doesn't provide any way to build the panel lazily (which is needed here). */ public class RenderablePanel extends ComplexPanel implements IsRenderable { private static Element hiddenDiv; private static String TAG_NAME = "div"; private static void ensureHiddenDiv() { // If it's already been created, don't do anything. if (hiddenDiv != null) { return; } hiddenDiv = Document.get().createDivElement(); UIObject.setVisible(hiddenDiv, false); RootPanel.getBodyElement().appendChild(hiddenDiv); } // TODO(rdcastro): Add setters for these, or maybe have a list instead of a // single callback. public ScheduledCommand wrapInitializationCallback = null; public ScheduledCommand detachedInitializationCallback = null; protected SafeHtml html = null; /** * Creates an HTML panel with the specified HTML contents inside a DIV * element. Any element within this HTML that has a specified id can contain a * child widget. * The actual element that will hold this HTML isn't initialized until it is * needed. * * @param html the panel's HTML */ public RenderablePanel(String html) { this(new SafeHtmlBuilder().appendHtmlConstant(html).toSafeHtml()); } /** * Initializes the panel's HTML from a given {@link SafeHtml} object. * * Similar to {@link #HTMLPanel(String)} * * @param safeHtml the html to set. */ public RenderablePanel(SafeHtml safeHtml) { this.html = safeHtml; setElement(PotentialElement.build(this, TAG_NAME)); } /** * Adds a child widget to the panel. * * @param widget the widget to be added */ @Override public void add(Widget widget) { add(widget, getElement()); } /** * Adds a child widget to the panel, replacing the HTML element. * * @param widget the widget to be added * @param toReplace the element to be replaced by the widget */ public final void addAndReplaceElement(Widget widget, Element toReplace) { com.google.gwt.user.client.Element clientElem = toReplace.cast(); addAndReplaceElement(widget, clientElem); } /** * Adds a child widget to the panel, replacing the HTML element. * * @param widget the widget to be added * @param toReplace the element to be replaced by the widget * @deprecated use {@link #addAndReplaceElement(Widget, Element)} */ @Deprecated public void addAndReplaceElement(Widget widget, com.google.gwt.user.client.Element toReplace) { // Logic pulled from super.add(), replacing the element rather than adding. widget.removeFromParent(); getChildren().add(widget); toReplace.getParentNode().replaceChild(widget.getElement(), toReplace); adopt(widget); } /** * Overloaded version for IsWidget. * * @see #addAndReplaceElement(Widget,Element) * * @deprecated use {@link #addAndReplaceElement(IsWidget, Element)} */ @Deprecated public void addAndReplaceElement(IsWidget widget, com.google.gwt.user.client.Element toReplace) { this.addAndReplaceElement(widget.asWidget(), toReplace); } /** * Overloaded version for IsWidget. * * @see #addAndReplaceElement(Widget,Element) */ public void addAndReplaceElement(IsWidget widget, Element toReplace) { this.addAndReplaceElement(widget.asWidget(), toReplace); } @Override public void claimElement(Element element) { if (isFullyInitialized()) { /* * If claimElement is being called after the widget is fully initialized, * that's probably a programming error, as it's much more efficient to * build the whole tree at once. */ throw new IllegalStateException( "claimElement() cannot be called twice, or after forcing the widget to" + " render itself (e.g. after adding it to a panel)"); } setElement(element); html = null; if (wrapInitializationCallback != null) { wrapInitializationCallback.execute(); wrapInitializationCallback = null; } } @Override public void initializeClaimedElement() { if (detachedInitializationCallback != null) { detachedInitializationCallback.execute(); detachedInitializationCallback = null; } } /** * Adopts the given, but doesn't change anything about its DOM element. * Should only be used for widgets with elements that are children of this * panel's element. * No-op if called with an {@link IsRenderable} that isn't also IsWidget, * but safe to call with such as a convenience. */ public void logicalAdd(IsRenderable renderable) { if (!(renderable instanceof IsWidget)) { // Nothing to do if not a Widget. return; } Widget widget = ((IsWidget) renderable).asWidget(); getChildren().add(widget); adopt(widget); } @Override public SafeHtml render(RenderableStamper stamper) { HtmlElementBuilder builder = PotentialElement.createBuilderFor(getElement()); stamper.stamp(builder); builder.html(getInnerHtml()).end(); SafeHtml returnValue = builder.asSafeHtml(); return returnValue; } @Override public void render(RenderableStamper stamper, SafeHtmlBuilder builder) { builder.append(render(stamper)); } @Override public Element resolvePotentialElement() { buildAndInitDivContainer(); html = null; return getElement(); } /** * Returns the HTML to be set as the innerHTML of the container. */ protected SafeHtml getInnerHtml() { return html; } /** * Whether the initilization of the panel is finished (i.e., the corresponding * DOM element has been built). */ protected boolean isFullyInitialized() { return html == null; } /** * Method that finishes the initialization of HTMLPanel instances built from * HTML. This will create a div to wrap the given HTML and call any callbacks * that may have been added to the panel. */ private void buildAndInitDivContainer() { // TODO(rdcastro): Use the same technique as in render() above. // Build the div that'll container the panel's HTML. Element element = Document.get().createDivElement(); element.setInnerSafeHtml(getInnerHtml()); // TODO(rdcastro): Implement something like // element.mergeFrom(getElement()); String styleName = getStyleName(); if (styleName != null) { element.setClassName(styleName); } setElement(element); // If there's any wrap callback to call, we have to attach the div before // calling it, and then detach again. if (wrapInitializationCallback != null) { ensureHiddenDiv(); hiddenDiv.appendChild(element); wrapInitializationCallback.execute(); element.getParentNode().removeChild(element); } // Call any detached init callbacks we might have. if (detachedInitializationCallback != null) { detachedInitializationCallback.execute(); } } }





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