The Wrestling Observer reports that the ending to Sunday night's WrestleMania 30 match between The Undertaker and Brock Lesnar was, in fact, the original plan that WWE and The Undertaker himself had set up from the beginning. The word is that this scenario was kept from pretty much everyone, but "betting odds started to change shortly before the match began."
They also note that back in 2010, The Undertaker was quoted as saying that he wanted Lesnar to be the one to end "The Streak" at WrestleMania.
The Wrestling Observer also reports what numerous other sources had reported regarding The Undertaker being taken to a local medical facility after it was feared that he suffered a concussion and neck injury, though as of this report, there are no updates as to whether or not The Undertaker suffered one or both of these injuries.
The general feeling is that The Undertaker's match at WrestleMania 30 was, in fact, his final match and that he is finished wrestling. However, we must stress that at this point, this is only being considered a rumor and has not been officially confirmed.