如何在usingaWizardNewFileCreationPage的同时结合使用BasicNewFileResourceWizard和初始文件上下文的文件扩展名？

public class CustomNewFileResourceWizard extends BasicNewFileResourceWizard {
    public void init(IWorkbench workbench, IStructuredSelection selection) {
        super.init(workbench, selection);
        setWindowTitle("Custom New File Wizard");
        setNeedsProgressMonitor(true);
        setDefaultPageImageDescriptor(ImageDescriptor.createFromURL(new URL("file:/path/to/image.png")));
        setFileExtension("txt"); // 设置默认的文件扩展名
    }
}

public class CustomNewFileCreationPage extends WizardNewFileCreationPage {
    private Text fileExtensionText;

    public CustomNewFileCreationPage(IStructuredSelection selection) {
        super("CustomNewFileCreationPage", selection);
        setTitle("Custom New File");
        setDescription("Create a new file with custom extension");
    }

    @Override
    public void createControl(Composite parent) {
        super.createControl(parent);
        Composite composite = (Composite) getControl();

        // 添加文件扩展名输入框
        Label fileExtensionLabel = new Label(composite, SWT.NONE);
        fileExtensionLabel.setText("File Extension:");
        fileExtensionText = new Text(composite, SWT.BORDER);
        fileExtensionText.setLayoutData(new GridData(GridData.FILL_HORIZONTAL));
    }

    public String getFileExtension() {
        return fileExtensionText.getText();
    }
}

public class CustomNewFileResourceWizard extends BasicNewFileResourceWizard {
    private CustomNewFileCreationPage creationPage;

    public void addPages() {
        super.addPages();
        creationPage = new CustomNewFileCreationPage(getSelection());
        addPage(creationPage);
    }

    public boolean performFinish() {
        String fileExtension = creationPage.getFileExtension();
        // 在这里可以根据文件扩展名进行相应的处理

        return super.performFinish();
    }
}