数据模型与BeanNode表示对象的双向同步

Question

I am interested in porting an app to the netbeans platform, but I am having difficulty understanding how to keep the connection between Nodes and the objects that they wrap up to date.

A main component of the existing app is a data model that is a hierarchical group of pojo/javabean objects. Some of the objects are containers used for grouping, and others are leaf node types. The model would typically have several hundred objects, with the deepest nesting being about 5 - 6 objects deep.

I understand how to take my data model and instantiate a tree of BeanNode objects: create ChildFactory classes that will walk through the data model and create a comparable tree of BeanNodes. So far so good. Once I have the Node structure then I can add an explorer to visualize the data, and then add actions to modify the Nodes (Add/Delete/Move).

Changes to the Nodes have to propagate back to the data model. The model can also be changed by events within the app that are not related to the netbeans platform, and these changes have to be propagated to the Node hierarchy.

Is there a standard idiom or Netbean features that can be used to manage the synchronization between a tree of Nodes and the data model?

Here are my thoughts so far: To keep the Nodes up to date with the data model I will have to let the Nodes listen to changes on the data model, and the data model will fire change events. Each Node object will listen for changes to the bean that is is wrapping, and react accordingly.

To have the data model keep up with changes to the Node presentation I can call methods on the data model during the actionPerformed methods that implement the Add/Delete/Move/etc actions.

How do I prevent echoing, where the change notifications keep bouncing back and forth between the two data structures?

Netbeans seems to be all about conventions on how to put the app together. Is there a convention for this data modeling problem?

Answer 1

"Changes to the Nodes have to propagate back to the data model. The model can also be changed by events within the app that are not related to the netbeans platform, and these changes have to be propagated to the Node hierarchy."

For the changes propagate back to your data model you just pass the data model to the node when creating it, and make all the changes to this same instance.

Changes made directly to the data model that need to be propagated to the note will require that you recreate the nodes passing the ChildrenFactory with your list of elements or that you work with a LookupListener.