[platform-ui-dev] arrays and generics in JFace

[Hendrik Still <hendrik.still@xxxxxxxxx>]

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Hi,
I'm currently adding generics support to the JFace Viewer. But run
into problems with the generic typisation of mostly object typed
arrays. I know arrays and generics do not mix very well. But I'm not
able to replace arrays by lists, because this would break the
compatibility top older versions.

But how should I type/cast the arrays correctly?

Here is an example from the
org.eclipse.jface.viewers.LabelProviderChangedEvent Classe:
- ------------------------------------------------------------

private Object[] elements;
//...
    public LabelProviderChangedEvent(IBaseLabelProvider source, Object
element) {
        super(source);
        this.elements = new Object[1];
        this.elements[0] = element;
    }

- ------------------------------------------------------------

First solution would be this:
- ------------------------------------------------------------
private E[] elements;
//...
    public LabelProviderChangedEvent(IBaseLabelProvider<E> source, E
element) {
        super(source);
	@SuppressWarnings("unchecked")
        this.elements = (E[]) new Object[1]; //Warning
        this.elements[0] = element;
    }
- ------------------------------------------------------------

Second would be this:
- ------------------------------------------------------------
public LabelProviderChangedEvent(IBaseLabelProvider<E> source, E
element) {
        super(source);
        ArrayList<E> arrayList = new ArrayList<E>();
        arrayList.add(element);
        this.elements = (E[]) arrayList.toArray();
    }
- ------------------------------------------------------------

What do you think is the better solution in the case of the JFace
Toolkit? Or do you have a better idea to solve this problem?

Regars,
Hendrik


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