/**

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  * General Public License Version 2 only ("GPL") or the Common

  * Development and Distribution License("CDDL") (collectively, the

  * "License"). You may not use this file except in compliance with the

  * License. You can obtain a copy of the License at

  * http://www.netbeans.org/cddl-gplv2.html

  * or nbbuild/licenses/CDDL-GPL-2-CP. See the License for the

  * specific language governing permissions and limitations under the

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  * nbbuild/licenses/CDDL-GPL-2-CP.  Oracle designates this

  * particular file as subject to the "Classpath" exception as provided

  * by Oracle in the GPL Version 2 section of the License file that

  * accompanied this code. If applicable, add the following below the

  * License Header, with the fields enclosed by brackets [] replaced by

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  * Contributor(s):

  *

  * The Original Software is NetBeans. The Initial Developer of the Original

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  * However, if you add GPL Version 2 code and therefore, elected the GPL

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 package net.java.html.boot.fx;

 import java.net.URL;

 import javafx.application.Platform;

 import javafx.beans.value.ChangeListener;

 import javafx.beans.value.ObservableValue;

 import javafx.concurrent.Worker;

 import javafx.scene.web.WebView;

 import net.java.html.BrwsrCtx;

 import net.java.html.boot.BrowserBuilder;

 import net.java.html.js.JavaScriptBody;

 import org.netbeans.html.boot.fx.AbstractFXPresenter;

 import org.netbeans.html.context.spi.Contexts;

 import org.netbeans.html.context.spi.Contexts.Id;

 /** Utility methods to use {@link WebView} and {@link JavaScriptBody} code

  * in existing <em>JavaFX</em> applications.

  * This class is for those who want to instantiate their own {@link WebView},

  * configure it manually, embed it into own <em>JavaFX</em>

  * application and based on other events in the application

  * {@link #runInBrowser(javafx.scene.web.WebView, java.lang.Runnable) re-execute code} 

  * inside of such {@link WebView}s.

  * In case such detailed control is not necessary,

  * consider using {@link BrowserBuilder}.

  * 

  * @author Jaroslav Tulach

  * @since 0.6

  */

 public final class FXBrowsers {

     private FXBrowsers() {

     }

     /** Enables the Java/JavaScript bridge (that supports {@link JavaScriptBody} and co.)

      * in the provided <code>webView</code>. This method returns 

      * immediately. Once the support is active, it calls back specified

      * method in <code>onPageLoad</code> class - the class can possibly be

      * loaded by a different classloader (to enable replacement of

      * methods with {@link JavaScriptBody} annotations with executable

      * versions). The method <code>methodName</code> needs to be <code>public</code>

      * (in a public class), <code>static</code> and take either no parameters

      * or an array of {@link String}s.

      * <p>

      * This method sets {@link WebView#getUserData()} and {@link #runInBrowser(javafx.scene.web.WebView, java.lang.Runnable)}

      * relies on the value. Please don't alter it.

      * <p>

      * Since introduction of {@link Id technology identifiers} the 

      * provided <code>args</code> strings are also passed to the 

      * {@link BrwsrCtx context} when it is being 

      * {@link Contexts#newBuilder(java.lang.Object...) created}

      * and can influence the selection

      * of available technologies 

      * (like {@link org.netbeans.html.json.spi.Technology},

      * {@link org.netbeans.html.json.spi.Transfer} or

      * {@link org.netbeans.html.json.spi.WSTransfer}).

      * 

      * @param webView the instance of Web View to tweak

      * @param url the URL of the HTML page to load into the view

      * @param onPageLoad callback class with method <code>methodName</code>

      * @param methodName the method to call when the page is loaded

      * @param args arguments to pass to the <code>methodName</code> method

      */

     public static void load(

         final WebView webView, final URL url, 

         Class<?> onPageLoad, String methodName,

         String... args

     ) {

         Object[] context = new Object[args.length + 1];

         System.arraycopy(args, 0, context, 1, args.length);

         context[0] = new Load(webView);

         BrowserBuilder.newBrowser(context).

             loadPage(url.toExternalForm()).

             loadClass(onPageLoad).

             invoke(methodName, args).

             showAndWait();

     }

     /** Enables the Java/JavaScript bridge (that supports {@link JavaScriptBody} and co.)

      * in the provided <code>webView</code>. This method returns 

      * immediately. Once the support is active, it calls back specified

      * method in <code>onPageLoad</code>'s run method. 

      * This is more convenient way to initialize the webview, 

      * but it requires one to make sure

      * all {@link JavaScriptBody} methods has been post-processed during

      * compilation and there will be no need to instantiate new classloader.

      * <p>

      * This method sets {@link WebView#getUserData()} and {@link #runInBrowser(javafx.scene.web.WebView, java.lang.Runnable)}

      * relies on the value. Please don't alter it.

      * 

      * @param webView the instance of Web View to tweak

      * @param url the URL of the HTML page to load into the view

      * @param onPageLoad callback to call when the page is ready

      * @since 0.8.1

      */

     public static void load(

         WebView webView, final URL url, Runnable onPageLoad

     ) {

         load(webView, url, onPageLoad, null);

     }

     /** Enables the Java/JavaScript bridge (that supports {@link JavaScriptBody} and co.)

      * in the provided <code>webView</code>. This method returns 

      * immediately. Once the support is active, it calls back specified

      * method in <code>onPageLoad</code>'s run method. 

      * This is more convenient way to initialize the webview, 

      * but it requires one to make sure

      * all {@link JavaScriptBody} methods has been post-processed during

      * compilation and there will be no need to instantiate new classloader.

      * <p>

      * This method sets {@link WebView#getUserData()} and {@link #runInBrowser(javafx.scene.web.WebView, java.lang.Runnable)}

      * relies on the value. Please don't alter it.

      * 

      * @param webView the instance of Web View to tweak

      * @param url the URL of the HTML page to load into the view

      * @param onPageLoad callback to call when the page is ready

      * @param loader the loader to use when constructing initial {@link BrwsrCtx} or <code>null</code>

      * @since 0.9

      */

     public static void load(

         WebView webView, final URL url, Runnable onPageLoad, ClassLoader loader

     ) {

         BrowserBuilder.newBrowser(new Load(webView)).

                 loadPage(url.toExternalForm()).

                 loadFinished(onPageLoad).

                 classloader(loader).

                 showAndWait();

     }

     /** Executes a code inside of provided {@link WebView}. This method

      * associates the {@link BrwsrCtx execution context} with provided browser,

      * so the {@link JavaScriptBody} annotations know where to execute

      * their JavaScript bodies.

      * The code is going to be executed synchronously

      * in case {@link Platform#isFxApplicationThread()} returns <code>true</code>.

      * Otherwise this method returns immediately and the code is executed

      * later via {@link Platform#runLater(java.lang.Runnable)}.

      * <p>

      * This method relies on {@link WebView#getUserData()} being properly

      * provided by the <code>load</code> methods in this class.

      * 

      * @param webView the web view previously prepared by one of the <code>load</code>

      *   methods in this class

      * @param code the code to execute

      * @throws IllegalArgumentException if the web view was not properly

      *   initialized

      * @see BrwsrCtx#execute(java.lang.Runnable) 

      * @since 0.8.1

      */

     public static void runInBrowser(WebView webView, Runnable code) {

         Object ud = webView.getUserData();

         if (!(ud instanceof Load)) {

             throw new IllegalArgumentException();

         }

         ((Load)ud).execute(code);

     }

     private static class Load extends AbstractFXPresenter {

         private final WebView webView;

         public Load(WebView webView) {

             webView.setUserData(this);

             this.webView = webView;

         }

         @Override

         protected void waitFinished() {

             // don't wait

         }

         @Override

         protected WebView findView(final URL resource) {

             final Worker<Void> w = webView.getEngine().getLoadWorker();

             w.stateProperty().addListener(new ChangeListener<Worker.State>() {

                 private String previous;

                 @Override

                 public void changed(ObservableValue<? extends Worker.State> ov, Worker.State t, Worker.State newState) {

                     if (newState.equals(Worker.State.SUCCEEDED)) {

                         if (checkValid()) {

                             onPageLoad();

                         }

                     }

                     if (newState.equals(Worker.State.FAILED)) {

                         checkValid();

                         throw new IllegalStateException("Failed to load " + resource);

                     }

                 }

                 private boolean checkValid() {

                     final String crnt = webView.getEngine().getLocation();

                     if (previous != null && !previous.equals(crnt)) {

                         w.stateProperty().removeListener(this);

                         return false;

                     }

                     previous = crnt;

                     return true;

                 }

             });

             return webView;

         }

     }

 }