1. A character stream search apparatus using a user-defined plurality of input streams, each of said streams processed one at a time, said character stream search apparatus (apparatus) for determining whether or not said plurality of input streams used as search objects exist in a character stream undergoing a search operation, said character stream comprising a plurality of characters, said apparatus comprising: software that uses a single user-defined Pgraph defining a from-to relationship between a plurality of nodes, said Pgraph possessing a start node, said start node being the first pattern to be searched for, said apparatus traversing said Pgraph as defined by said from-to relationships, said nodes each comprising a single pattern, each of said nodes having associated with it a user-defined tag, each of said nodes having associated with it zero or more user-defined actions, each of said actions determining what processing is to be performed by said software when said node patterns are recognized in the character stream.