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
private IElementChangedListener fElementListener;
	private boolean fAllowCollapsing= false;
	private boolean fCollapseJavadoc= false;
	private boolean fCollapseImportContainer= true;
	private boolean fCollapseInnerTypes= true;
	private boolean fCollapseMethods= false;
	private boolean fCollapseHeaderComments= true;
	
	private IType fFirstType;
	private boolean fHasHeaderComment;
	
	/**
	 * Member filter, matches nested members (but not top-level types).
	 * @since 3.2
	 */
	private final Filter fMemberFilter = new Filter() {
		public boolean match(JavaProjectionAnnotation annotation) {
			if (!annotation.isCollapsed() && !annotation.isComment() && !annotation.isMarkedDeleted()) {
				IJavaElement element= annotation.getElement();
				if (element instanceof IMember) {
					if (element.getElementType() != IJavaElement.TYPE || ((IMember) element).getDeclaringType() != null) {
						annotation.markCollapsed();
						return true;
					}
				}
			}
			return false;
		}
	};