Bug 112586 [api] add support for toggling folding for IJavaElement's
For tools that want to use the IJavaFoldingStructureProviderExtension, but want finer-grained control of what to collapse, it would be useful to have the following methods: - collapseElements(List<IJavaElement> elements) - expandElements(List<IJavaElement> elements) My use case is Mylar, which currently needs to set it's own folding structure provider, but with this could simply use the default one and drive the folding based on selections. Note that for selections this would only be getting called with a single element, but when a file is opened it would need to be called with a list, hance the suggest to take lists (or arrays if JDT is not moving to Java 5).
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/text/folding/DefaultJavaFoldingStructureProvider.java
/**
	 * Collapses all annotations matched by the passed filter.
	 * 
	 * @param filter the filter to use to select which annotations to collapse
	 * @since 3.2
	 */
	private void collapseMatches(Filter filter) {
		if (!isInstalled())
			return;
		ProjectionAnnotationModel model= (ProjectionAnnotationModel) fEditor.getAdapter(ProjectionAnnotationModel.class);
		if (model == null)
			return;
		
		List modified= new ArrayList();
		Iterator iter= model.getAnnotationIterator();
		while (iter.hasNext()) {
			Object annotation= iter.next();
			if (annotation instanceof JavaProjectionAnnotation) {
				JavaProjectionAnnotation java= (JavaProjectionAnnotation) annotation;
				
				if (filter.match(java))
					modified.add(java);
				
			}
		}
		
		model.modifyAnnotations(null, null, (Annotation[]) modified.toArray(new Annotation[modified.size()]));
	}
}