DDSQueryCondition Class Reference

<<interface>> These are specialised DDSReadCondition objects that allow the application to also specify a filter on the locally available data. More...

Inheritance diagram for DDSQueryCondition:

Public Member Functions
virtual const char *	get_query_expression ()=0
	Retrieves the query expression.
virtual DDS_ReturnCode_t	get_query_parameters (DDS_StringSeq &query_parameters)=0
	Retrieves the query parameters.
virtual DDS_ReturnCode_t	set_query_parameters (const DDS_StringSeq &query_parameters)=0
	Sets the query parameters.
Public Member Functions inherited from DDSReadCondition
virtual DDS_SampleStateMask	get_sample_state_mask ()=0
	Retrieves the set of sample_states for the condition.
virtual DDS_ViewStateMask	get_view_state_mask ()=0
	Retrieves the set of view_states for the condition.
virtual DDS_InstanceStateMask	get_instance_state_mask ()=0
	Retrieves the set of instance_states for the condition.
virtual DDSDataReader *	get_datareader ()=0
	Returns the DDSDataReader associated with the DDSReadCondition.
Public Member Functions inherited from DDSCondition
virtual DDS_Boolean	get_trigger_value ()=0
	Retrieve the trigger_value.

Detailed Description

<<interface>> These are specialised DDSReadCondition objects that allow the application to also specify a filter on the locally available data.

Each query condition filter is composed of a DDSReadCondition state filter and a content filter expressed as a query_expression and query_parameters.

The query (query_expression) is similar to an SQL WHERE clause and can be parameterised by arguments that are dynamically changeable by the set_query_parameters() operation.

Two query conditions that have the same query_expression will require unique query condition content filters if their query_paramters differ. Query conditions that differ only in their state masks will share the same query condition content filter.

Queries and Filters Syntax describes the syntax of query_expression and query_parameters.

Member Function Documentation

virtual const char* DDSQueryCondition::get_query_expression ( )

pure virtual

Retrieves the query expression.

virtual DDS_ReturnCode_t DDSQueryCondition::get_query_parameters ( DDS_StringSeq &  query_parameters )

pure virtual

Retrieves the query parameters.

Parameters

query_parameters

<<inout>> the query parameters are returned here. The memory for the strings in this sequence is managed according to the conventions described in Conventions. In particular, be careful to avoid a situation in which RTI Connext allocates a string on your behalf and you then reuse that string in such a way that RTI Connext believes it to have more memory allocated to it than it actually does.

virtual DDS_ReturnCode_t DDSQueryCondition::set_query_parameters ( const DDS_StringSeq &  query_parameters )

pure virtual

Sets the query parameters.

Parameters

query_parameters

<<in>> the new query parameters