JList和ListModel设计模式建议

Question

I am building an application which is basically just a GUI for displaying and editing one single object. Since the class for this object was created with JAXB , it is basically a tree with many Strings and integers as children, but there are also some List<E> s. For each simple child JAXB provides a getter and a setter, but for all lists only a getter is provided, since it gives a reference to the internal list, which can now be modified.

Since I need to display every child (and branch for that matter) in a separate swing GUI component, I need these views to handle some data. According to my current knowledge about the model view controller design pattern, I should strictly separate the model from the view. Following this, it would be a bad idea to let a JList operate directly on an internal list of my base object. (Actually doing so would be a pretty easy solution to my specific use case, but since additional functionality might be added later on, I think I should refrain from this idea.)

Then I started thinking: If I do not let the components work on the list directly, I have to make them use a copy of the original. But since I cannot set the original list to a new one returned by my GUI component, I have to copy the items another time when saving the view data to my model. Also, it would not be wise to hand out references to internal lists of a custom ListModel , which would mean, that depending on the depth of the GUI structure, the list may be copied additional times.

Since I also want my application to be efficient, this does also not seem like the correct approach. How do I build this "correctly"?

Summary:

• The List<E> from the original object is a reference to an internal list of the object.

• The JList displaying the list should not get this reference, hence it must copy the list.

• Getting the list from the JList should not yield in a reference to the internal list either, hence it must be copied again.

• Saving the list to the original object must copy the list a third time, because the original object does not have a setter method for the list. (see above for details)

Is my grasp on this correct? How do I build this properly and make it efficient?

PS: Adding setter methods to the original class structure is not an option!

Answer 1

was created with JAXB , it is basically a tree with many Strings and integers as children, but there are also some List<E> s. For each simple child JAXB provides a getter and a setter, but for all lists only a getter is provided, since it gives a reference to the internal list, which can now be modified.

see

• JTreeTable

• JList (unmodifiable), better could be JTable (with / without JTableHeader) in JTree

Answer 2

All of the components suggested by @mKorbel provide some kind of selection listener that will allow you to loosely couple a selection in one panel to the selected item's display in another. FileBrowser illustrates a TreeSelectionListener ; Outline can have a ListSelectionListener , shown here ; etc.

Addendum: In this related example , DisplayPanel listens to an adjacent TableModel , which it can query to update a model in one of it's own components. Note that each model is loosely coupled to its respective view. Common notification mechanisms are mentioned here .