如何让实现IPageLoader的PaginationService在Eclipse Job中运行？

可以实现你的需求。原loadPage()方法是同步执行的，直接调用会阻塞UI线程。我们需要将其封装到Eclipse Job中实现异步加载，同时通过回调机制通知调用方加载结果，并利用进度监控展示加载状态。

具体实现步骤 #

1. 添加加载回调接口 #

定义回调接口，用于在后台加载完成/失败时通知调用方：

public interface PageLoadCallback {
    // 加载成功时触发
    void onPageLoaded(PageResult<NebulaWidget> result);
    // 加载失败时触发
    void onLoadFailed(Throwable exception);
}

2. 修改PaginationService类 #

在原有基础上添加异步加载方法、回调字段，将数据加载逻辑放入Job中：

import java.util.ArrayList;
import java.util.List;
import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.Status;
import org.eclipse.core.runtime.jobs.Job;
import org.eclipse.nebula.widgets.pagination.IPageLoader;
import org.eclipse.nebula.widgets.pagination.PageableController;
import org.eclipse.nebula.widgets.pagination.collections.PageResult;
import org.eclipse.nebula.widgets.pagination.example.model.NebulaWidget;
import org.eclipse.nebula.widgets.pagination.example.model.Person;
import org.eclipse.swt.widgets.Display;

public class PaginationService implements IPageLoader<PageResult<NebulaWidget>> {

    private List<NebulaWidget> widgets;
    private PageLoadCallback callback;

    public PaginationService() {
        this.widgets = new ArrayList<>();
    }

    // 设置加载回调
    public void setPageLoadCallback(PageLoadCallback callback) {
        this.callback = callback;
    }

    // 异步加载分页数据的入口方法
    public void loadPageAsync(final PageableController controller) {
        Job loadJob = new Job("加载分页数据") {
            @Override
            protected IStatus run(IProgressMonitor monitor) {
                // 初始化进度任务
                monitor.beginTask("正在加载第" + (controller.getCurrentPage() + 1) + "页", 100);
                try {
                    // 模拟服务器请求耗时（实际项目中替换为真实的API调用）
                    Thread.sleep(1000);
                    monitor.worked(50);

                    // 执行原有的数据加载逻辑
                    PageResult<NebulaWidget> result = loadPage(controller);
                    monitor.worked(50);

                    // 在UI线程中通知加载完成
                    Display.getDefault().asyncExec(() -> {
                        if (callback != null) {
                            callback.onPageLoaded(result);
                        }
                    });
                } catch (InterruptedException e) {
                    // 任务被取消
                    monitor.setCanceled(true);
                    Display.getDefault().asyncExec(() -> {
                        if (callback != null) {
                            callback.onLoadFailed(new RuntimeException("加载已取消"));
                        }
                    });
                    return Status.CANCEL_STATUS;
                } catch (Exception e) {
                    // 加载失败
                    Display.getDefault().asyncExec(() -> {
                        if (callback != null) {
                            callback.onLoadFailed(e);
                        }
                    });
                    return new Status(IStatus.ERROR, "your.plugin.id", "分页数据加载失败", e);
                } finally {
                    monitor.done();
                }
                return Status.OK_STATUS;
            }
        };
        // 标记为用户可见任务，允许在进度视图中显示和取消
        loadJob.setUser(true);
        // 启动后台任务
        loadJob.schedule();
    }

    @Override
    public PageResult<NebulaWidget> loadPage(PageableController controller) {
        int pageOffset = controller.getPageOffset();
        widgets.clear();
        switch (pageOffset) {
            case 10:
                loadpage2();
                break;
            case 20:
                loadpage3();
                break;
            default:
                loadpage1();
        }
        return new PageResult<>(widgets, 25);
    }

    // 以下为原有的数据填充方法，保持不变
    private void loadpage1() {
        Person tomSchindl = new Person("Tom", "Schindl");
        addWidget("Grid", "An custom table/tree widget which provides Excel like features and a JFaceViewer integration ", tomSchindl);
        addWidget("PShelf", "The PShelf widget is a composite widget that is similar to a tab folder. It contains items which can be selected to show their client areas.", tomSchindl);
        addWidget("PGroup", "The PGroup widget is a expandable/collapsible composite widget with attractive styling and an extensible design.", tomSchindl);

        Person nicolasRicheton = new Person("Nicolas", "Richeton");
        addWidget("Gallery", "This SWT widget displays images or items in a grid-like presentation. Gallery is very useful to display images in a photo viewer or files in an explorer-like view.", nicolasRicheton);

        Person eliasVolanakis = new Person("Elias", "Volanakis");
        addWidget("CompositeTable", "An custom table/tree widget which provides Excel like features and a JFaceViewer integration ", eliasVolanakis);

        Person donaldDunne = new Person("Donald", "Dunne");
        addWidget("XViewer", "The purpose of the XViewer is to give the application developer a more advanced and dynamic TreeViewer that has the filtering and sorting ", donaldDunne);
        addWidget("CalendarCombo", "The Calendar Combo Widget is a combo box widget that opens a calendar when dropped down. ", donaldDunne);

        Person wimJongman = new Person("Wim", "Jongman");
        addWidget("Oscilloscope", "A widget showing an Oscilloscope", wimJongman);

        Person martyJones = new Person("Marty", "Jones");
        addWidget("TableCombo", "A DropDown-Widget which uses a Table to display the items ", martyJones);

        Person ahmedMahran = new Person("Ahmed", "Mahran ");
        addWidget("STW", "A component which allows to implement transitions ", ahmedMahran);
    }

    private void loadpage2() {
        Person nicolasRicheton = new Person("Nicolas", "Richeton");
        Person emilCrumhorn = new Person("Emil", "Crumhorn");
        addWidget("Gantt", "A comprehensive implementation of a Gantt chart.", emilCrumhorn);

        Person jeremyDowdall = new Person("Jeremy", "Dowdall");
        addWidget("CDateTime", "A Date and Time selector widget.", jeremyDowdall);

        addWidget("CWT", "Nebula animation ", nicolasRicheton);

        Person tomSchindl = new Person("Tom", "Schindl");
        addWidget("BidiLayout", "The PGroup widget is a expandable/collapsible composite widget with attractive styling and an extensible design.", tomSchindl);

        Person mattHall = new Person("Matt", "Hall");
        addWidget("PaperClips", "Printing Library", mattHall);
        addWidget("Radio Group", "Group of Radio Buttons", emilCrumhorn);

        addWidget("Collapsible Buttons", "Widget modeled after the bottom left buttons widget in Microsoft Outlook ", emilCrumhorn);

        Person ericWuillai = new Person("Eric", "Wuillai");
        addWidget("Date Chooser", "Presents the monthly view of a calendar for date picking.", ericWuillai);
        addWidget("Formatted Text", "A decorator component adding input and display mask capabilities on a Text widget.", ericWuillai);

        Person lukaszMilewski = new Person("Lukasz", "Milewski");
        addWidget("Nebula Toolbar", "A comprehensive implementation of a Gantt chart. ", lukaszMilewski);
    }

    private void loadpage3() {
        Person jeremyDowdall = new Person("Jeremy", "Dowdall");
        Person mickaelIstria = new Person("Mickael", "Istria");
        addWidget("TreeMapper", "Mapping between Tree's", mickaelIstria);

        Person angeloZerr = new Person("Angelo", "Zerr");
        addWidget("Picture Control", "A control managing (download and display) a picture.", angeloZerr);
        addWidget("Pagination Control", "A control managing paginated list and display pagination navigation bar.", angeloZerr);

        addWidget("CTree", "", jeremyDowdall);

        Person edwinPark = new Person("Edwin", "Park");
        addWidget("NatTable", "NatTable is a powerful and flexible SWT table/grid widget that is built to handle very large data sets, real-time updates, dynamic styling, and more.", edwinPark);
    }

    private void addWidget(String name, String description, Person committer) {
        this.widgets.add(new NebulaWidget(name, description, committer));
    }
}

3. 使用异步加载服务 #

在UI代码中初始化服务、设置回调，并触发异步加载：

import org.eclipse.nebula.widgets.pagination.PageableController;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.MessageBox;
import org.eclipse.swt.widgets.Shell;

public class PaginationDemo {
    public static void main(String[] args) {
        Display display = new Display();
        Shell shell = new Shell(display);

        // 初始化分页控制器
        PageableController controller = new PageableController();
        // 初始化分页服务
        PaginationService service = new PaginationService();

        // 设置加载回调
        service.setPageLoadCallback(new PageLoadCallback() {
            @Override
            public void onPageLoaded(PageResult<NebulaWidget> result) {
                // 更新UI：将结果设置到分页控件，更新控制器总条数
                // 示例：pageableTable.setInput(result.getContent());
                controller.setTotalElements(result.getTotalElements());
                controller.updatePage();
                MessageBox msgBox = new MessageBox(shell);
                msgBox.setMessage("第" + (controller.getCurrentPage()+1) + "页加载完成，共" + result.getContent().size() + "条数据");
                msgBox.open();
            }

            @Override
            public void onLoadFailed(Throwable exception) {
                // 处理加载失败，弹出错误提示
                MessageBox msgBox = new MessageBox(shell);
                msgBox.setMessage("加载失败：" + exception.getMessage());
                msgBox.open();
            }
        });

        // 触发第一页的异步加载
        service.loadPageAsync(controller);

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

关键说明 #

• Eclipse Job：负责后台执行耗时操作，setUser(true)让任务在Eclipse进度视图中可见，用户可随时取消。
• 进度监控：通过IProgressMonitor实时更新加载进度，提升用户体验。
• 线程安全：后台线程不能直接操作SWT控件，必须通过Display.asyncExec()切换到UI线程更新界面。
• 回调机制：解决异步任务无法直接返回结果的问题，确保加载完成后能通知调用方处理结果。

内容的提问来源于stack exchange，提问作者jemrug