有没有办法通过编程定义MToolberElements在MToolBar中的位置？

Question

我正在开发一个Eclipse rcp应用程序，其中提供了各种插件。每个插件都有自己的处理器，可以通过编程将更多元素插入到可能存在的MToolbares中（使用现有的MToolBarElements）。插入元素的顺序取决于插件的初始化顺序，除了插件之间的依赖关系外，初始化顺序是不确定的。但是，在插件之间创建一个人工依赖项来强制插件的初始化顺序并不是一种选择。

是否有一种开箱即用的方法来相对于彼此排列元素？例如，元素X必须始终以id“foo.bar”插入元素Y之后的工具栏。或者我必须自己管理元素添加到工具栏的顺序？

每个插件都定义了自己的处理器

public class ApplicationModelProcessor {
  @Execute 
  public void execute(
    final MApplication application, 
    final ToolBarBuilder toolbarBuilder) {
  // ToolBarBuilder is a class providing methods to configure toolbar
  // elements and appending them to existing toolbars. So after the
  // configuration of the builder "build" is called and toolbar elements
  // are added to (existing) toolbars according to the configuration of
  // the builder
  toolbarBuilder.doSomeConfiguration();
  toolbarBuilder.build();
}

在ToolBarBuilder类中，存在一个方法updateToolItem，该方法有效地将MToolberElement添加到MToolBar中

public class TooBarBuilder {
  public MToolBarElement build() {
    // The code happening here basically searches for existing MToolBar or 
    // creates a new MToolBar according to a given configuration of the 
    // builder
    MToolBar toolbar = findOrCreateToolBar();

    // and adds a new MToolBarElement to the given MToolBar
    return updateToolItem(toolbar);
  }


  // This method is invoked at some point during the execution of the provided processor. The toolBar is looked up before and provided to the method-
  private MToolBarElement updateToolItem(final MToolBar toolBar) {
    final MToolBarElement result = createHandleToolItem();

    // At this point I could manage the order by myself but is there a better way to do this?
    toolBar.getChildren().add(result);

    return result;
  }
}

一些插件将MToolBarElements提供给相同的MToolBar，尽管它们自己的Application ationModelProcess在“org.eclipse.e4.workbench.model”扩展点注册。

提供工具栏项目1和2的插件

另一个插件提供工具栏项3

启动应用程序时

然后，工具栏项目的顺序必须恒定（项目的绝对顺序并不重要，但顺序应始终保持不变）

目前有时为1,2,3或3,2,1

Answer 1

最终的解决方案是将实现从直接将MToolBarElements添加到MToolBar更改为添加MToolBar贡献，并让Eclipse负责将MToolBarElements由MToolBarContripution重新增强到MToolBar中的正确位置：

@Creatable
public class TooBarBuilder {

  @Inject
  private MApplication application;

  private String positionInParent;

  // The positionInParent is an expression that represents a position
  // relative to another element in the MToolBar, for example:
  // "after=another.toolbar.item.id"
  public ToolBarBuilder positionInParent(final String positionInParent) {
    this.positionInParent = positionInParent;
    return this;
  }

  public MToolBarElement build() {
    // The code happening here basically searches for existing MToolBar or 
    // creates a new MToolBar according to a given configuration of the 
    // builder
    MToolBar toolbar = findOrCreateToolBar();

    // and adds a new MToolBarElement to the given MToolBar
    return updateToolItem(toolbar);
  }


  // This method is invoked at some point during the execution of the provided processor. 
  // The toolBar is looked up before and provided to the method.
  private MToolBarElement updateToolItem(final MToolBar toolBar) {
    final MToolBarElement result = createHandleToolItem();
    MToolBarContribution contribution = MMenuFactory.INSTANCE.createToolBarContribution();
    contribution.setElementId(getContributionId()); // any elementId is ok, details how the id is created are not of interest for the solution
    contribution.setParentId(toolbar.getElementId());
    contribution.setPositionInParent(positionInParent);

    // after all model processors have been executed the MToolBarContribtions 
    // are evaluated. MToolBarElements in the created MToolBarContributions 
    // are added to the MToolBars referenced by the parentId. During this process 
    // the MToolBarElements are positioned relatively to each other according to
    // "positionInParent"
    application.getToolBarContributions().add(contribution);
  }
}