# Appendix F. Core mappers While filters are applied to the `content` of files, Mappers are applied to the `filenames`. All mappers have the same API, i.e. the way you use them is the same: `<mapper type="`mappername`" from="`frompattern`" to="`topattern`" />`# @#@#@#@#@idp346 F.1 Common Attributes Table F.1:聽 Attributes for the `<mapper>` tag NameTypeDescriptionDefaultRequired`type``String`Type of the mapper.n/aOne of these is required.`classname``String`Dot-path to a custom mapper class to use.n/a`from``String`The pattern the filename is to be matched to. The exact meaning is dependent on the implementation of the mapper.n/adepends on the implementation of the mapper`to``String`The pattern according to which the filename is to be changed to. Here, the usage is dependent on the implementation of the mapper, too.n/adepends on the implementation of the mapper