dds::sub::cond::dds::sub::cond::QueryCondition Class Reference

<<reference-type>> Specialized ReadCondition that allows applications to also specify a filter on the data available in a dds::sub::DataReader More...

#include <dds/sub/cond/QueryCondition.hpp>

Inheritance diagram for dds::sub::cond::dds::sub::cond::QueryCondition:

Public Types
typedef DELEGATE::iterator	iterator
	Parameter iterator. A random-access iterator of std::string.
typedef DELEGATE::const_iterator	const_iterator
	Parameter iterator. A random-access iterator of std::string.

Public Member Functions
	QueryCondition (const dds::sub::Query &query, const dds::sub::status::DataState &status)
	Creates a QueryCondition.
template<typename Functor >
	QueryCondition (const dds::sub::Query &query, const dds::sub::status::DataState &status, const Functor &functor)
	Creates a QueryCondition with a handler.
std::string	expression () const
	Gets the expression.
dds::core::StringSeq	parameters () const
	Gets the parameters.
template<typename FWIterator >
void	parameters (const FWIterator &begin, const FWIterator &end)
	Modifies the query parameters.
uint32_t	parameters_length () const
	Gets the number of parameters.
Public Member Functions inherited from dds::sub::cond::ReadCondition
template<typename T >
	ReadCondition (const dds::sub::DataReader< T > &reader, const dds::sub::status::DataState &status)
	Creates a ReadCondition.
template<typename T , typename Functor >
	ReadCondition (const dds::sub::DataReader< T > &reader, const dds::sub::status::DataState &status, const Functor &handler)
	Creates a ReadCondition with a handler.
const dds::sub::status::DataState	state_filter () const
	Returns the DataState of this condition.
const AnyDataReader &	data_reader () const
	Returns the DataReader associated to this condition.
void	close ()
	Closes the ReadCondition.
bool	closed () const
	Indicates whether this ReadCondition has been closed with close().
Public Member Functions inherited from dds::core::cond::Condition
void	dispatch ()
	Dispatches the functors that have been registered with the condition.
bool	trigger_value () const
	This operation retrieves the trigger_value of the Condition.

Detailed Description

<<reference-type>> Specialized ReadCondition that allows applications to also specify a filter on the data available in a dds::sub::DataReader

Each query condition filter is composed of a dds::sub::cond::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.

See Also

Filtering with Query Conditions

Member Typedef Documentation

typedef DELEGATE::iterator dds::sub::cond::dds::sub::cond::QueryCondition::iterator

Parameter iterator. A random-access iterator of std::string.

typedef DELEGATE::const_iterator dds::sub::cond::dds::sub::cond::QueryCondition::const_iterator

Parameter iterator. A random-access iterator of std::string.

Constructor & Destructor Documentation

dds::sub::cond::dds::sub::cond::QueryCondition::QueryCondition ( const dds::sub::Query &  query, const dds::sub::status::DataState &  status  )

inline

Creates a QueryCondition.

Parameters

query	The query
status	The sample, view and instance states of interest.

See Also

ReadCondition

template<typename Functor >

dds::sub::cond::dds::sub::cond::QueryCondition::QueryCondition ( const dds::sub::Query &  query, const dds::sub::status::DataState &  status, const Functor &  functor  )

inline

Creates a QueryCondition with a handler.

This constructor is similar to this ReadCondition constructor.

Member Function Documentation

std::string dds::sub::cond::dds::sub::cond::QueryCondition::expression ( ) const

inline

Gets the expression.

dds::core::StringSeq dds::sub::cond::dds::sub::cond::QueryCondition::parameters ( ) const

inline

Gets the parameters.

Provides the begin iterator to the parameter list. The end iterator to the parameter list. Provides the begin iterator to the parameter list. The end iterator to the parameter list.

template<typename FWIterator >

void dds::sub::cond::dds::sub::cond::QueryCondition::parameters ( const FWIterator &  begin, const FWIterator &  end  )

inline

Modifies the query parameters.

Template Parameters

FWIterator

A forward iterator whose value type is std::string (or convertible to std::string).

Parameters

begin	The beginning of the range of parameters
end	The end of the range

uint32_t dds::sub::cond::dds::sub::cond::QueryCondition::parameters_length ( ) const

inline

Gets the number of parameters.