I created a new viewer that I think may be really useful. I’m writing this post to provide a high-level description. You can use it as follows:

final TokenViewer tokenViewer = new TokenViewer(root);

tokenViewer.getControl().setLayoutData(

new GridData(GridData.FILL_HORIZONTAL));

tokenViewer.setContentProvider(new BaseWorkbenchContentProvider());

tokenViewer.setLabelProvider(new WorkbenchLabelProvider());

tokenViewer.setInput(workspaceRoot);

The result is a simple text field with following services:

1. Content assist.
2. Object-oriented IStructuredSelection support – if the user enters proper string the selection event is thrown. If user sets selection – string will appear in the text entry.
3. Easy and familiar programming model – I guess any JFace/Eclipse plugin developer wrote dozens of those label/content providers.

TokenViewer working with workspace

This simple API works for the case when text in the text field is the same as a label in the content assist pop-up. But once you want to have different text (i.e. SSN entry may show employee name in the pop-up) you will need something more specific for this task and that is why I defined special content provider (I still hope it is easier to use then regular JFace content assist API):

public interface ITokenContentProvider extends IStructuredContentProvider {

Object fromString(Object parent, String value);

String toString(Object object);

Object[] getChildren(Object object, String prefix);

}

• fromString method will return a child of the given parent node that corresponds to a specific string. It may return null.
• toString will convert given object to its string representation.
• getChildren tries to find all the elements that correspond to given string.

If the viewer is provided with IStructuredContentProvider (or ITreeContentProvider) it will wrap it with a custom adapter so you can use your existing code.

The label provider is used to decorate the content assist pop-up. I also have a slightly extended label provider interface:

public interface IDescriptionProvider extends ILabelProvider {

public String getDescription(Object element);

}

This optional extension provides the way to provide extended object descriptions that are shown along the content assist pop-up:

This is also a tokenviewer

Note – red squiggles are automatically shown when there is no object that corresponds to a text.

What I’m going to implement next is:

1. Multiple selection support when token list is separated with some delimeter.
2. Rich text (HTML?) support both for content assist pop-up and description pop-up.