Java tutorial
/******************************************************************************* * Copyright (c) 2000, 2018 IBM Corporation and others. * * This program and the accompanying materials * are made available under the terms of the Eclipse Public License 2.0 * which accompanies this distribution, and is available at * https://www.eclipse.org/legal/epl-2.0/ * * SPDX-License-Identifier: EPL-2.0 * * Contributors: * IBM Corporation - initial API and implementation *******************************************************************************/ package org.eclipse.swt.snippets; /* * Browser example snippet: call Java from JavaScript. * * For a list of all SWT example snippets see * http://www.eclipse.org/swt/snippets/ * * @since 3.5 */ import org.eclipse.swt.*; import org.eclipse.swt.browser.*; import org.eclipse.swt.layout.*; import org.eclipse.swt.widgets.*; public class Snippet307 { public static void main(String[] args) { Display display = new Display(); Shell shell = new Shell(display); shell.setText("Snippet 307"); shell.setLayout(new FillLayout()); shell.setBounds(10, 10, 300, 200); final Browser browser; try { browser = new Browser(shell, SWT.NONE); } catch (SWTError e) { System.out.println("Could not instantiate Browser: " + e.getMessage()); display.dispose(); return; } browser.setText(createHTML()); final BrowserFunction function = new CustomFunction(browser, "theJavaFunction"); browser.addProgressListener(ProgressListener.completedAdapter(event -> { browser.addLocationListener(new LocationAdapter() { @Override public void changed(LocationEvent event) { browser.removeLocationListener(this); System.out.println("left java function-aware page, so disposed CustomFunction"); function.dispose(); } }); })); shell.open(); while (!shell.isDisposed()) { if (!display.readAndDispatch()) display.sleep(); } display.dispose(); } static class CustomFunction extends BrowserFunction { CustomFunction(Browser browser, String name) { super(browser, name); } @Override public Object function(Object[] arguments) { System.out.println("theJavaFunction() called from javascript with args:"); for (int i = 0; i < arguments.length; i++) { Object arg = arguments[i]; if (arg == null) { System.out.println("\t-->null"); } else { System.out.println("\t-->" + arg.getClass().getName() + ": " + arg.toString()); } } Object returnValue = new Object[] { Short.valueOf((short) 3), true, null, new Object[] { "a string", false }, "hi", Float.valueOf(2.0f / 3.0f), }; //int z = 3 / 0; // uncomment to cause a java error instead return returnValue; } } static String createHTML() { StringBuilder buffer = new StringBuilder(); buffer.append("<html>\n"); buffer.append("<head>\n"); buffer.append("<script language=\"JavaScript\">\n"); buffer.append("function function1() {\n"); buffer.append(" var result;\n"); buffer.append(" try {\n"); buffer.append(" result = theJavaFunction(12, false, null, [3.6, ['swt', true]], 'eclipse');\n"); buffer.append(" } catch (e) {\n"); buffer.append(" alert('a java error occurred: ' + e.message);\n"); buffer.append(" return;\n"); buffer.append(" }\n"); buffer.append(" for (var i = 0; i < result.length; i++) {\n"); buffer.append(" alert('returned ' + i + ': ' + result[i]);\n"); buffer.append(" }\n"); buffer.append("}\n"); buffer.append("</script>\n"); buffer.append("</head>\n"); buffer.append("<body>\n"); buffer.append("<input id=button type=\"button\" value=\"Push to Invoke Java\" onclick=\"function1();\">\n"); buffer.append("<p><a href=\"http://www.eclipse.org\">go to eclipse.org</a>\n"); buffer.append("</body>\n"); buffer.append("</html>\n"); return buffer.toString(); } }