15. An apparatus according to claim 14 , wherein the processor is further configured to: provide the decision tree for detecting the predetermined data, the decision tree comprising a plurality of states, each said state being linked with at least one other state by a respective condition, the arrangement of linked states forming a plurality of paths; and compare the token types of the sequence of tokens to respective conditions in the decision tree to match the sequence of tokens to one or more paths in the tree, wherein the predetermined data can be detected without using an epsilon reduction to take account of at least one said optional token type.
16. An apparatus according to claim 15 , wherein the predetermined data is at least one of a physical address, an IP address, an e-mail address, a time, a day, a date, and a contact number.