question: public static QueryTask . QuerySpecification buildTaskStatusQuerySpec ( final Class taskClass , final TaskState . TaskStage ... stages ) { checkArgument ( stages != null && stages . length >= 1 , "stages.length must be >= 1" ) ; String fieldName = findStageFieldName ( taskClass ) ; if ( null == fieldName ) { throw new IllegalArgumentException ( String . format ( "%s does not have a member of type %s" , taskClass , TaskState . class ) ) ; } QueryTask . Query stageQuery = buildTaskStateQuery ( String . format ( STAGE_FIELD_NAME_FORMAT , fieldName ) , stages ) ; return buildQuerySpec ( taskClass , stageQuery ) ; }
target:  Builds a query specification which will query for service instances of type taskClass with the stage field one of the values passed in as a parameter.