6.10. Filter Functions

GeoMesa provides several custom CQL filter functions, which can be used for filtering or transforming query results. Filter functions can be created through ECQL.toFilter, or directly through FilterFactory2.function.

6.10.1. currentDate

Returns the current date as a java.util.Date. Accepts an optional offset, specified as an ISO-8601 duration string. See the Oracle Javadoc for details on duration parsing.

6.10.2. dateToLong

Converts a java.util.Date to a Long representing milliseconds since the epoch, as returned by date.getTime().

6.10.3. jsonPath

See JSONPath CQL Filter Function.

6.10.4. proxyId

Converts the current FeatureId to an Int. This may be used to minimize data size, while providing a unique lookup mechanism. In particular, when returning data using Arrow Encoding, the feature ID can be proxied down to four bytes. When retrieving the full feature, the spatio-temporal values can be used to provide a fast lookup, and the proxy ID can be used for disambiguation.

6.10.5. visibility

Evaluates the current user’s authorizations against a feature’s visibility markings. Accepts an optional parameter to specify the feature attribute that contains the visibility marking, otherwise will use the default user-data location.