Refactor SWT JavaScript support

[gpl/argeo-suite.git] / swt / org.argeo.app.swt / src / org / argeo / app / swt / js / SwtBrowserJsPart.java

diff --git a/swt/org.argeo.app.swt/src/org/argeo/app/swt/js/SwtBrowserJsPart.java b/swt/org.argeo.app.swt/src/org/argeo/app/swt/js/SwtBrowserJsPart.java
new file mode 100644 (file)
index 0000000..8ae34d5
--- /dev/null
+++ b/swt/org.argeo.app.swt/src/org/argeo/app/swt/js/SwtBrowserJsPart.java
@@ -0,0 +1,146 @@
+package org.argeo.app.swt.js;
+
+import java.util.Locale;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.CompletionStage;
+import java.util.function.Function;
+
+import org.argeo.api.cms.CmsLog;
+import org.eclipse.swt.SWT;
+import org.eclipse.swt.browser.Browser;
+import org.eclipse.swt.browser.BrowserFunction;
+import org.eclipse.swt.browser.ProgressEvent;
+import org.eclipse.swt.browser.ProgressListener;
+import org.eclipse.swt.layout.GridData;
+import org.eclipse.swt.layout.GridLayout;
+import org.eclipse.swt.widgets.Composite;
+import org.eclipse.swt.widgets.Control;
+
+/**
+ * A part using a {@link Browser} and remote JavaScript components on the client
+ * side.
+ */
+public class SwtBrowserJsPart {
+       private final static CmsLog log = CmsLog.getLog(SwtBrowserJsPart.class);
+
+       private final static String GLOBAL_THIS_ = "globalThis.";
+
+       private final Browser browser;
+       private final CompletableFuture<Boolean> pageLoaded = new CompletableFuture<>();
+
+       public SwtBrowserJsPart(Composite parent, int style, String url) {
+               this.browser = new Browser(parent, 0);
+               if (parent.getLayout() instanceof GridLayout)
+                       browser.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));
+               // TODO other layouts
+
+               browser.setUrl(url);
+               browser.addProgressListener(new ProgressListener() {
+                       static final long serialVersionUID = 1L;
+
+                       @Override
+                       public void completed(ProgressEvent event) {
+                               try {
+                                       init();
+                                       loadExtensions();
+                                       pageLoaded.complete(true);
+                               } catch (Exception e) {
+                                       log.error("Cannot initialise " + url + " in browser", e);
+                                       pageLoaded.complete(false);
+                               }
+                       }
+
+                       @Override
+                       public void changed(ProgressEvent event) {
+                       }
+               });
+       }
+
+       /*
+        * LIFECYCLE
+        */
+
+       /** Called when the page has been loaded. */
+       protected void init() {
+       }
+
+       /** To be overridden with calls to {@link #loadExtension(String)}. */
+       protected void loadExtensions() {
+
+       }
+
+       protected void loadExtension(String url) {
+//                     String js = """
+//                                     var script = document.createElement("script");
+//                                     script.src = '%s';
+//                                     document.head.appendChild(script);
+//                                     """;
+//                     browser.evaluate(String.format(Locale.ROOT, js, url));
+               browser.evaluate(String.format(Locale.ROOT, "import('%s')", url));
+       }
+
+       protected CompletionStage<Boolean> getReadyStage() {
+               return pageLoaded.minimalCompletionStage();
+       }
+
+       /*
+        * JAVASCRIPT ACCESS
+        */
+
+       /**
+        * Execute this JavaScript on the client side after making sure that the page
+        * has been loaded and the map object has been created.
+        * 
+        * @param js   the JavaScript code, possibly formatted according to
+        *             {@link String#format}, with {@link Locale#ROOT} as locale (for
+        *             stability of decimal separator, as expected by JavaScript.
+        * @param args the optional arguments of
+        *             {@link String#format(String, Object...)}
+        */
+       protected CompletionStage<Object> evaluate(String js, Object... args) {
+               CompletableFuture<Object> res = pageLoaded.thenApply((ready) -> {
+                       if (!ready)
+                               throw new IllegalStateException("Component is not initialised.");
+                       Object result = browser.evaluate(String.format(Locale.ROOT, js, args));
+                       return result;
+               });
+               return res.minimalCompletionStage();
+       }
+
+       /** @return the globally usable function name. */
+       protected String createJsFunction(String name, Function<Object[], Object> toDo) {
+               // browser functions must be directly on window (RAP specific)
+               new BrowserFunction(browser, name) {
+
+                       @Override
+                       public Object function(Object[] arguments) {
+                               Object result = toDo.apply(arguments);
+                               return result;
+                       }
+
+               };
+               return "window." + name;
+       }
+
+       /** Directly executes */
+       protected void doExecute(String js, Object... args) {
+               browser.execute(String.format(Locale.ROOT, js, args));
+       }
+
+       protected CompletionStage<Object> callMethod(String jsObject, String methodCall, Object... args) {
+               return evaluate(jsObject + '.' + methodCall, args);
+       }
+
+       protected String getJsVarName(String name) {
+               return GLOBAL_THIS_ + name;
+       }
+
+       /*
+        * ACCESSORS
+        */
+       
+       public Control getControl() {
+               return browser;
+       }
+
+}