"There are many ways to filter news feeds from your favorite sources... For the purpose of this post, however, we'll focus on services that let you filter by keyword.
<dispatcher>FORWARD</dispatcher>
<dispatcher>REQUEST</dispatcher>
INCLUDE: Use this for the filter to be applied to any include targets matching a specified servlet name or with URLs matching a specified pattern.
FORWARD: Use this for the filter to be applied to any forward targets matching a specified servlet name or with URLs matching a specified pattern.
REQUEST: Use this in addition to an INCLUDE or FORWARD setting (one <dispatcher> element for each setting) for the filter to also be applied to direct request targets matching a specified servlet name or with URLs matching a specified pattern. (It is nonsensical to use the REQUEST value only. If you want the filter to apply only to direct requests, there is no need to use the <dispatcher> element.)
ERROR: Use this for the filter to be applied under the error page mechanism.
S. Mehrotra, M. Kaur, M. Charaya, and D. Patel. International Journal on Recent and Innovation Trends in Computing and Communication, 3 (4):
2202--2207(April 2015)
X. Peng, E. Goodman, and R. Rosenberg. Genetic Programming Theory and Practice IV, volume 5 of Genetic and Evolutionary Computation, chapter 5, Springer, Ann Arbor, (11-13 May 2006)
S. Czerwinski, B. Zhao, T. Hodes, A. Joseph, and R. Katz. MobiCom '99: Proceedings of the 5th annual ACM/IEEE international
conference on Mobile computing and networking, page 24--35. New York, NY, USA, ACM, (1999)