对轮廓节点进行分组

发布于 2024-11-27 18:05:17 字数 686 浏览 3 评论 0原文

我正在开发 XTEXT 2.0 插件。我想将轮廓内的一些节点分组到“虚拟”节点中。达到这个结果的正确方法是什么？

目前，如果我想对“A”类型的节点进行分组，在我的 OutlineTreeProvider 中，我定义以下方法

protected void _createNode(IOutlineNode parentNode, A node) {
 if(this.myContainerNode == null){
  A container = S3DFactoryImpl.eINSTANCE.createA();
  super._createNode(parentNode, container);
  List<IOutlineNode> children = parentNode.getChildren();
  this.myContainerNode = children.get(children.size()-1);
 }
 super._createNode(this.myContainerNode, node);
}

阅读 Xtext 2.0 文档，我还看到有一个 EStructuralFeatureNode。我不太明白这种类型的节点是什么以及如何使用它。您能解释一下 EStructuralFeatureNode 的用途吗？

非常感谢

原文

I'm developing an XTEXT 2.0 plugin. I'd like to group some nodes inside my outline in a "virtual" node. Which is the right way to achieve this result?

Currently if i want to group nodes of type "A", in my OutlineTreeProvider I define the following method

protected void _createNode(IOutlineNode parentNode, A node) {
 if(this.myContainerNode == null){
  A container = S3DFactoryImpl.eINSTANCE.createA();
  super._createNode(parentNode, container);
  List<IOutlineNode> children = parentNode.getChildren();
  this.myContainerNode = children.get(children.size()-1);
 }
 super._createNode(this.myContainerNode, node);
}

Reading the Xtext 2.0 documentation i saw also that there is a EStructuralFeatureNode. I didn't understand exactly what this type of node is and how to use it. Can you explain what EStructuralFeatureNode is used for?

Many thanks

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只为守护你 2024-12-04 18:05:17

您的代码存在一些问题：

this.myContainerNode：无法保证您的提供程序是原型；有人可以将实例配置为单例。因此，请避免实例字段。

此问题有两种解决方案：

每当需要时在父节点中搜索容器节点（缓慢但简单）
将缓存添加到实例（请参阅如何将一些缓存信息附加到 Eclipse 编辑器或资源？）

super._createNode()：不要调用带有 _ 的方法，始终调用普通版本 (super.createNode())。该方法将确定要为您调用哪个重载的 _create* 方法。但在你的情况下，你不能调用任何这些方法，因为你会得到一个循环。请改为调用 createEObjectNode()。

最后，您不需要创建 A 的实例 (S3DFactoryImpl.eINSTANCE.createA())。节点可以由模型元素支持，但这是可选的。

对于分组，我使用此类：

public class VirtualOutlineNode extends AbstractOutlineNode {
    protected VirtualOutlineNode( IOutlineNode parent, Image image, Object text, boolean isLeaf ) {
        super( parent, image, text, isLeaf );
    }
}

在您的情况下，代码如下所示：

protected void _createNode(IOutlineNode parentNode, A node) {
    VirtualOutlineNode group = findExistingNode();
    if( null == group ) {
        group = new VirtualOutlineNode( parentNode, null, "Group A", false );
    }
    // calling super._createNode() or super.createNode() would create a loop
    createEObjectNode( group, node );
}

There are a couple of problems with your code:

this.myContainerNode: There is no guarantee that your provider is a prototype; someone could configure the instance as singleton. Therefore, avoid instance fields.

There are two solutions to this problem:

Search the parent node for your container node whenever you need it (slow but simple)
Add a cache to your instance (see How do I attach some cached information to an Eclipse editor or resource?)

super._createNode(): Don't call the methods with _, always call the plain version (super.createNode()). That method will figure out which overloaded _create* method to call for you. But in your case, you can't call any of these methods because you'd get a loop. Call createEObjectNode() instead.

Lastely, you don't need to create an instance of A (S3DFactoryImpl.eINSTANCE.createA()). Nodes can be backed by model elements but that's optional.

For grouping, I use this class:

public class VirtualOutlineNode extends AbstractOutlineNode {
    protected VirtualOutlineNode( IOutlineNode parent, Image image, Object text, boolean isLeaf ) {
        super( parent, image, text, isLeaf );
    }
}

In your case, the code would look like so:

protected void _createNode(IOutlineNode parentNode, A node) {
    VirtualOutlineNode group = findExistingNode();
    if( null == group ) {
        group = new VirtualOutlineNode( parentNode, null, "Group A", false );
    }
    // calling super._createNode() or super.createNode() would create a loop
    createEObjectNode( group, node );
}

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