1. A data processing method of identifying a document within a block of text, comprising: tokenizing a block of text into a plurality of text tokens according to at least one rule parser; comparing each of the plurality of text tokens to a plurality of document tokens sequentially and determining if a text token matches one of the plurality of document tokens, wherein the plurality of document tokens correspond to one or more of a plurality of documents which have been tokenized according to the at least one rule parser; filtering each matched text token according to predetermined filtering criteria to generate one or more candidate text tokens; and matching a sequence of candidate text tokens from the one or more candidate text tokens to a sequence of document tokens, wherein the sequence of candidate text tokens occurs in sequential order within the block of text.