| Name | Description | Type | Package | Framework |
| ConcatenateFunction | The function concatenates strings. | Class | org.geotools.filter.function.string | GeoTools |
| StringInFunction | Class | org.geotools.filter.function.string | GeoTools | |
| StringTemplateFunction | StringTemplate function, applies a regular expression with capturing groups, and them uses the groups to build a new string based on the provided template. | Class | org.geotools.filter.function | GeoTools |