DDS::QueryCondition Class Reference

<<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.
void	get_query_parameters (StringSeq^ query_parameters)
	Retrieves the query parameters.
void	set_query_parameters (StringSeq^ query_parameters)
	Sets the query parameters.
virtual System::Boolean	get_trigger_value () override
	Retrieve the trigger_value.
Public Member Functions inherited from DDS::ReadCondition
System::UInt32	get_sample_state_mask ()
	Retrieves the set of sample_states for the condition.
System::UInt32	get_view_state_mask ()
	Retrieves the set of view_states for the condition.
System::UInt32	get_instance_state_mask ()
	Retrieves the set of instance_states for the condition.
DataReader^	get_datareader ()
	Returns the DDS::DataReader associated with the DDS::ReadCondition.

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

System::String ^ DDS::QueryCondition::get_query_expression

(

)

Retrieves the query expression.

void DDS::QueryCondition::get_query_parameters

(

StringSeq^

query_parameters

)

Retrieves the query parameters.

Parameters

query_parameters

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

void DDS::QueryCondition::set_query_parameters

(

StringSeq^

query_parameters

)

Sets the query parameters.

Parameters

query_parameters

<<in>> the new query parameters

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

overridevirtual

Retrieve the trigger_value.

Returns

the trigger value.

Reimplemented from DDS::ReadCondition.