swt/org.argeo.app.swt/src/org/argeo/app/swt/js/SwtBrowserJsPart.java

   1 package org.argeo.app.swt.js;
   2
   3 import java.util.ArrayList;
   4 import java.util.List;
   5 import java.util.Locale;
   6 import java.util.concurrent.CompletableFuture;
   7 import java.util.concurrent.CompletionStage;
   8 import java.util.function.Function;
   9
  10 import org.argeo.api.cms.CmsLog;
  11 import org.argeo.app.ux.js.JsClient;
  12 import org.eclipse.swt.SWT;
  13 import org.eclipse.swt.browser.Browser;
  14 import org.eclipse.swt.browser.BrowserFunction;
  15 import org.eclipse.swt.browser.ProgressEvent;
  16 import org.eclipse.swt.browser.ProgressListener;
  17 import org.eclipse.swt.layout.GridData;
  18 import org.eclipse.swt.layout.GridLayout;
  19 import org.eclipse.swt.widgets.Composite;
  20 import org.eclipse.swt.widgets.Control;
  21 import org.eclipse.swt.widgets.Display;
  22
  23 /**
  24  * A part using a {@link Browser} and remote JavaScript components on the client
  25  * side.
  26  */
  27 public class SwtBrowserJsPart implements JsClient {
  28         private final static CmsLog log = CmsLog.getLog(SwtBrowserJsPart.class);
  29
  30         private final static String GLOBAL_THIS_ = "globalThis.";
  31
  32         private final Browser browser;
  33         private final CompletableFuture<Boolean> readyStage = new CompletableFuture<>();
  34
  35         /**
  36          * Tasks that were requested before the context was ready. Typically
  37          * configuration methods on the part while the user interfaces is being build.
  38          */
  39         private List<PreReadyToDo> preReadyToDos = new ArrayList<>();
  40
  41         public SwtBrowserJsPart(Composite parent, int style, String url) {
  42                 this.browser = new Browser(parent, 0);
  43                 if (parent.getLayout() instanceof GridLayout)
  44                         browser.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));
  45                 // TODO other layouts
  46
  47                 browser.setUrl(url);
  48                 browser.addProgressListener(new ProgressListener() {
  49                         static final long serialVersionUID = 1L;
  50
  51                         @Override
  52                         public void completed(ProgressEvent event) {
  53                                 try {
  54                                         init();
  55                                         loadExtensions();
  56                                         // execute todos in order
  57                                         for (PreReadyToDo toDo : preReadyToDos) {
  58                                                 toDo.run();
  59                                         }
  60                                         preReadyToDos.clear();
  61                                         readyStage.complete(true);
  62                                 } catch (Exception e) {
  63                                         log.error("Cannot initialise " + url + " in browser", e);
  64                                         readyStage.complete(false);
  65                                 }
  66                         }
  67
  68                         @Override
  69                         public void changed(ProgressEvent event) {
  70                         }
  71                 });
  72         }
  73
  74         /*
  75          * LIFECYCLE
  76          */
  77
  78         /**
  79          * Called when the page has been loaded, typically in order to initialise
  80          * JavaScript objects. One MUST use {@link #doExecute(String, Object...)} in
  81          * order to do so, since the context is not yet considered ready and calls to
  82          * {@link #evaluate(String, Object...)} will block.
  83          */
  84         protected void init() {
  85         }
  86
  87         /**
  88          * To be overridden with calls to {@link #loadExtension( Supplier<Boolean> toDo
  89          * = () -> { boolean success = browser.execute(); return success; }; String)}.
  90          */
  91         protected void loadExtensions() {
  92
  93         }
  94
  95         protected void loadExtension(String url) {
  96 //                      String js = """
  97 //                                      var script = document.createElement("script");
  98 //                                      script.src = '%s';
  99 //                                      document.head.appendChild(script);
 100 //                                      """;
 101 //                      browser.evaluate(String.format(Locale.ROOT, js, url));
 102                 browser.evaluate(String.format(Locale.ROOT, "import('%s')", url));
 103         }
 104
 105         public CompletionStage<Boolean> getReadyStage() {
 106                 return readyStage.minimalCompletionStage();
 107         }
 108
 109         /*
 110          * JAVASCRIPT ACCESS
 111          */
 112
 113         @Override
 114         public Object evaluate(String js, Object... args) {
 115                 assert browser.getDisplay().equals(Display.findDisplay(Thread.currentThread())) : "Not the proper UI thread.";
 116                 if (!readyStage.isDone())
 117                         throw new IllegalStateException("Methods returning a result can only be called after UI initialisation.");
 118                 // wait for the context to be ready
 119 //              boolean ready = readyStage.join();
 120 //              if (!ready)
 121 //                      throw new IllegalStateException("Component is not initialised.");
 122                 Object result = browser.evaluate(String.format(Locale.ROOT, js, args));
 123                 return result;
 124         }
 125
 126         @Override
 127         public void execute(String js, Object... args) {
 128                 String jsToExecute = String.format(Locale.ROOT, js, args);
 129                 if (readyStage.isDone()) {
 130                         boolean success = browser.execute(jsToExecute);
 131                         if (!success)
 132                                 throw new RuntimeException("JavaScript execution failed.");
 133                 } else {
 134                         PreReadyToDo toDo = new PreReadyToDo(jsToExecute);
 135                         preReadyToDos.add(toDo);
 136                 }
 137         }
 138
 139         @Override
 140         public String createJsFunction(String name, Function<Object[], Object> toDo) {
 141                 // browser functions must be directly on window (RAP specific)
 142                 new BrowserFunction(browser, name) {
 143
 144                         @Override
 145                         public Object function(Object[] arguments) {
 146                                 Object result = toDo.apply(arguments);
 147                                 return result;
 148                         }
 149
 150                 };
 151                 return "window." + name;
 152         }
 153
 154         /**
 155          * Directly executes, even if {@link #getReadyStage()} is not completed. Except
 156          * in initialisation, {@link #evaluate(String, Object...)} should be used
 157          * instead.
 158          */
 159         protected void doExecute(String js, Object... args) {
 160                 browser.execute(String.format(Locale.ROOT, js, args));
 161         }
 162
 163         @Override
 164         public String getJsVarName(String name) {
 165                 return GLOBAL_THIS_ + name;
 166         }
 167
 168         class PreReadyToDo implements Runnable {
 169                 private String js;
 170
 171                 public PreReadyToDo(String js) {
 172                         this.js = js;
 173                 }
 174
 175                 @Override
 176                 public void run() {
 177                         boolean success = browser.execute(js);
 178                         if (!success)
 179                                 throw new IllegalStateException("Pre-ready JavaScript failed: " + js);
 180                 }
 181         }
 182
 183         /*
 184          * ACCESSORS
 185          */
 186
 187         public Control getControl() {
 188                 return browser;
 189         }
 190
 191 }