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

#include <managed_subscription.h>

Inheritance diagram for DDS::QueryCondition:

Public Member Functions
System::String ^	get_query_expression ()
	Retrieves the query expression. More...

void	get_query_parameters (StringSeq^ query_parameters)
	Retrieves the query parameters. More...

void	set_query_parameters (StringSeq^ query_parameters)
	Sets the query parameters. More...

virtual System::Boolean	get_trigger_value () override
	Retrieve the `trigger_value`. More...

Public Member Functions inherited from DDS::ReadCondition
System::UInt32	get_sample_state_mask ()
	Retrieves the set of `sample_states` for the condition. More...

System::UInt32	get_view_state_mask ()
	Retrieves the set of `view_states` for the condition. More...

System::UInt32	get_instance_state_mask ()
	Retrieves the set of `instance_states` for the condition. More...

System::UInt32	get_stream_kind_mask ()
	Retrieves the set of stream kind mask for the condition. More...

DataReader ^	get_datareader ()
	Returns the DDS::DataReader associated with the DDS::ReadCondition. More...

Detailed Description

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

Each query condition filter is composed of a DDS::ReadCondition 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

◆ get_query_expression()

System::String ^ DDS::QueryCondition::get_query_expression ( )

Retrieves the query expression.

◆ get_query_parameters()

void DDS::QueryCondition::get_query_parameters ( StringSeq^ query_parameters )

Retrieves the query parameters.

Parameters

query_parameters <<inout>> the query parameters are returned here.

◆ set_query_parameters()

void DDS::QueryCondition::set_query_parameters ( StringSeq^ query_parameters )

Sets the query parameters.

Parameters

query_parameters <<in>> the new query parameters

◆ get_trigger_value()

virtual System::Boolean DDS::QueryCondition::get_trigger_value ( )

overridevirtual

Retrieve the trigger_value.

Returns: the trigger value.