Eclipse Tutorial

EMF DataBinding Tutorial

在了解EMF DataBinding之前，你首先应该对JFace DataBinding有所了解。

简介

首先，将org.eclipse.emf.databinding加到依赖项中，查看EMFProperties类中的相关选项。总体来说可以将EMF的DataBinding项分成两类，一类是基于EStructuredFeature的，另一类是基于FeaturePath的。

其次，搞清楚绑定的对象是Value还是List或Set的。

EMFProperties

// Name value of library;
EMFProperties.value(LibraryPackage.eINSTANCE.getLibrary_Name()).observe(library)

// Book list of library
EMFProperties.value(LibraryPackage.eINSTANCE.getLibrary_Books()).observe(library)

示例

    Display display = new Display();
    Shell shell = new Shell(display);
    shell.setText("EMF DataBinding Example");

    shell.setLayout(new GridLayout(2, true));

    Composite control = new Composite(shell, SWT.NONE);
    control.setLayout(new GridLayout(2, false));
    control.setLayoutData(new GridData(GridData.FILL_BOTH
            | GridData.GRAB_HORIZONTAL | GridData.GRAB_VERTICAL));

    // Model
    final Library library = LibraryFactory.eINSTANCE.createLibrary();
    LibraryFactory factory = LibraryFactory.eINSTANCE;

    library.setName("Ecsoya");

    Book book = factory.createBook();
    book.setTitle("King Lear");

    Writer writer = factory.createWriter();
    writer.setName("William Shakespeare");
    book.setWriter(writer);

    library.getBooks().add(book);

    final ResourceSet resourceSet = new ResourceSetImpl();
    resourceSet
            .getResourceFactoryRegistry()
            .getExtensionToFactoryMap()
            .put(Resource.Factory.Registry.DEFAULT_EXTENSION,
                    new XMLResourceFactoryImpl());
    resourceSet.getPackageRegistry().put(LibraryPackage.eNS_URI,
            LibraryPackage.eINSTANCE);
    final Resource resource = resourceSet.createResource(URI
            .createFileURI("demo.xml"));
    resource.getContents().add(library);

    Composite content = new Composite(shell, SWT.NONE);
    content.setLayoutData(new GridData(GridData.FILL_BOTH
            | GridData.GRAB_HORIZONTAL | GridData.GRAB_VERTICAL));
    content.setLayout(new GridLayout());
    Button button = new Button(content, SWT.NONE);
    button.setText("Update...");
    final Text contentText = new Text(content, SWT.BORDER | SWT.V_SCROLL
            | SWT.H_SCROLL);
    contentText.setLayoutData(new GridData(GridData.FILL_BOTH
            | GridData.GRAB_HORIZONTAL | GridData.GRAB_VERTICAL));
    button.addListener(SWT.Selection, new Listener() {

        @Override
        public void handleEvent(Event event) {

            try {
                ByteArrayOutputStream stream = new ByteArrayOutputStream(
                        100);
                resource.save(stream, Collections.EMPTY_MAP);
                contentText.setText(new String(stream.toByteArray()));
                stream.close();
            } catch (IOException e) {
                contentText.setText("");
            }
        }
    });

    // Widgets
    Label label = new Label(control, SWT.NONE);
    label.setText("Library:");

    // Library name
    final Text text = new Text(control, SWT.BORDER);

    // Books
    label = new Label(control, SWT.NONE);
    label.setText("Books:");
    final TableViewer tableViewer = new TableViewer(control);
    tableViewer.getTable().setHeaderVisible(true);
    tableViewer.getTable().setLayoutData(
            new GridData(SWT.FILL, SWT.FILL, true, true, 1, 1));
    tableViewer.setContentProvider(new ArrayContentProvider());

    TableViewerColumn nameCol = new TableViewerColumn(tableViewer, SWT.NONE);
    nameCol.getColumn().setText("Title");
    nameCol.getColumn().setWidth(150);
    nameCol.setLabelProvider(new ColumnLabelProvider() {
        public String getText(Object element) {
            if (element instanceof Book) {
                return ((Book) element).getTitle();
            }
            return super.getText(element);
        }
    });

    TableViewerColumn writerCol = new TableViewerColumn(tableViewer,
            SWT.NONE);
    writerCol.getColumn().setText("Writer");
    writerCol.getColumn().setWidth(150);
    writerCol.setLabelProvider(new ColumnLabelProvider() {
        public String getText(Object element) {
            if (element instanceof Book) {
                Writer writer = ((Book) element).getWriter();
                return writer == null ? "" : writer.getName();
            }
            return super.getText(element);
        }
    });

    final Realm realm = SWTObservables.getRealm(display);
    Realm.runWithDefault(realm, new Runnable() {

        @Override
        public void run() {

            DataBindingContext context = new DataBindingContext(realm);

            // Bind name of library to a text.
            context.bindValue(
                    WidgetProperties.text(SWT.Modify).observe(text),

                    // Name value of library;
                    EMFProperties.value(
                            LibraryPackage.eINSTANCE.getLibrary_Name())
                            .observe(library),

                    new UpdateValueStrategy(
                            UpdateValueStrategy.POLICY_UPDATE),
                    new UpdateValueStrategy(
                            UpdateValueStrategy.POLICY_UPDATE));

            //
            context.bindValue(
                    ViewerProperties.input().observe(tableViewer),

                    // Book list of library
                    EMFProperties.value(
                            LibraryPackage.eINSTANCE.getLibrary_Books())
                            .observe(library),

                    new UpdateValueStrategy(
                            UpdateValueStrategy.POLICY_UPDATE),
                    new UpdateValueStrategy(
                            UpdateValueStrategy.POLICY_UPDATE));
        }
    });

    shell.open();
    while (!shell.isDisposed()) {
        if (!display.readAndDispatch()) {
            display.sleep();
        }
    }
    display.dispose();

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