# Package org.jbpm.services.api.query

- Interface Summary
  Interface | Description
  --- | ---
  QueryParamBuilder<T> | QueryParamBuilder is responsible for building up one or more filter parameters.
  QueryParamBuilderFactory | Factory for query param builders that can be constructed based on: identifier set of parameters - key value pairs
  QueryResultMapper<T> | Maps raw data set into object instances.
  QueryService | Advanced queries service that allows to register custom queries that will be equipped with tailored capabilities of querying data.

- Class Summary
  Class | Description
  --- | ---
  NamedQueryMapper<T> | A delegate mapper that will delay look up of actual mapper to the time its `map` method is invoked.
  QueryMapperRegistry | Allow to find mappers by name instead of using their instances Mappers are discovered by ServiceLoader mechanism - meaning must be defined in services file: META-INF/services/org.jbpm.services.api.query.QueryResultMapper as fully qualified class names that implement `org.jbpm.services.api.query.QueryResultMapper`

- Exception Summary
  Exception | Description
  --- | ---
  QueryAlreadyRegisteredException |
  QueryNotFoundException |