Patent ID: 8266135

Claim:
A method for building an electronic index to support efficient evaluation of complex regular expressions, comprising: specifying index feature classes to extract index terms from a collection of documents and to identify metadata associated with the index terms to be stored in an electronic index of the collection of documents, wherein each index term is a sequence of characters and character classes and each character class is a variable representing characters from a pre-determined set of characters; applying the feature classes over the collection of documents to generate the index storing the metadata; receiving a query regular expression, wherein the query regular expression is composed of multiple constraints and wherein each constraint is associated with one of the feature classes; extracting the constraints from the query regular expression and transforming said constraints into a new query over the index; executing the new query over the index to identify a subset of documents in the collection of documents over which the regular expression query can be evaluated; and returning the identified subset of documents over which the regular expression is queried.