Provides page and content filtering functionality for JSPWiki.

## Package specification

PageFilters are objects which can influence the way a page is translated from WikiMarkup to HTML, or change the content when the page is saved. They're fairly versatile, and you can do lots of interesting stuff with them, ranging from adding your own WikiMarkup rules to purifying your HTML to making a spam filter to counting popularity of pages.

## Related documentation

TBD.