/**
* Finds the parent of a blip. The parent is the preceding blip in the thread, or the blip to
* which the thread is a reply for the first blip in a thread. The first blip of the root thread
* has no parent.
*
* @param blip the blip.
* @return the blip's parent, or {@code null} if the blip is the first blip in a conversation.
*/
@Override
public ConversationBlip findBlipParent(ConversationBlip blip) {
ConversationThread containingThread = blip.getThread();
if (containingThread.getFirstBlip() == blip
&& containingThread != blip.getConversation().getRootThread()) {
return containingThread.getParentBlip();
}
return findPreviousSibling(blip);
}
