IWorkspaceHandle and IVersionableHandle?

Hi,

I'm looking at the first code snippet on this page:
https://jazz.net/wiki/bin/view/Main/RTCSDK20_SourceControl

ITeamRepository repo = ...;
IWorkspaceHandle workspaceHandle = ...;
IVersionableHandle versionableHandle = ...;

//fetch workspace from IItemManager
IItemManager itemManager = repo.itemManager();
IWorkspace workspace = (IWorkspace) itemManager.fetchCompleteItem(workspaceHandle, monitor);

//fetch workspace connection from IWorkspaceManager
IWorkspaceManager workspaceManager = SCMPlatform.getWorkspaceManager(repo);
IWorkspaceConnection workspaceConnection = workspaceManager.getWorkspaceConnection(workspaceHandle, monitor);

//fetch a list of components from IItemManager
List<IComponentHandle> componentHandles = workspace.getComponents();
List<IComponent> components = itemManager.fetchCompleteItems(components, componentHandles);

//fetch a versionable from IConfiguration
IComponentHandle componentHandle = components.get(0);
IConfiguration configuration = workspaceConnection.configuration(componentHandle);
IVersionable versionable = configuration.fetchCompleteItem(versionable);

//cast IVersionable to IFileItem
if (IFileItem.ITEM_TYPE.equals(versionable.getItemType())) {
IFileItem file = (IFileItem) versionable;
}

Can someone please clarify the purpose of IWorkspaceHandle and IVersionableHandle? How should I initialize workspaceHandle and versionbleHandle?

Thanks!