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

QueryCondition objects are specialized ReadCondition objects that allow the application to also specify a filter on the locally available data. More...

#include "QueryCondition.hpp"

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

Public Types
typedef DELEGATE::const_iterator	const_iterator
typedef DELEGATE::iterator	iterator

Public Member Functions
	QueryCondition (const dds::sub::Query &query, const dds::sub::status::DataState &status)
template<typename FUN >
	QueryCondition (const dds::sub::Query &query, const dds::sub::status::DataState &status, FUN &functor)
template<typename FUN >
	QueryCondition (const dds::sub::Query &query, const dds::sub::status::DataState &status, const FUN &functor)
	QueryCondition (const dds::sub::AnyDataReader &dr, const std::string &expression, const std::vector< std::string > &params, const dds::sub::status::DataState &status)
template<typename FUN >
	QueryCondition (const dds::sub::AnyDataReader &dr, const std::string &expression, const std::vector< std::string > &params, const dds::sub::status::DataState &status, FUN &functor)
template<typename FUN >
	QueryCondition (const dds::sub::AnyDataReader &dr, const std::string &expression, const std::vector< std::string > &params, const dds::sub::status::DataState &status, const FUN &functor)
void	add_parameter (const std::string &param)
const_iterator	begin () const
iterator	begin ()
const dds::sub::AnyDataReader &	data_reader () const
void	dispatch ()
const_iterator	end () const
iterator	end ()
const std::string &	expression () const
void	expression (const std::string &expr)
const std::string &	expression ()
template<typename Functor >
void	handler (Functor &func)
template<typename Functor >
void	handler (const Functor &func)
bool	is_nil () const
template<typename R >
bool	operator!= (const R &ref) const
bool	operator!= (const null_type nil) const
DELEGATE *	operator-> ()
const DELEGATE *	operator-> () const
template<typename R >
bool	operator== (const R &ref) const
bool	operator== (const null_type) const
template<typename FWIterator >
void	parameters (const FWIterator &begin, const FWIterator end)
uint32_t	parameters_length () const
void	reset_handler ()
const dds::sub::status::DataState	state_filter () const
bool	trigger_value () const

Detailed Description

QueryCondition objects are specialized ReadCondition objects that allow the application to also specify a filter on the locally available data.

The query (query_expression) is similar to an SQL WHERE clause can be parameterized by arguments. See dds::sub::Query for more query information.

See the WaitSet examples for some examples.
Although the WaitSet examples use the StatusCondition, the basic usage of this Condition with a WaitSet is the same.

See also

dds::sub::Query

dds::core::cond::Condition

dds::sub::cond::ReadCondition

WaitSet concept

Subscription concept

SQL expression info

WaitSet examples

Definition at line 62 of file QueryCondition.hpp.

Member Typedef Documentation

const_iterator

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

Iterator for the query expression parameters.

Definition at line 80 of file QueryCondition.hpp.

iterator

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

Iterator for the query expression parameters.

Definition at line 75 of file QueryCondition.hpp.

Constructor & Destructor Documentation

QueryCondition() [1/6]

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

Creates a QueryCondition instance.

This will create an QueryCondition that is associated with a dds::sub::Query, which is again associated with a dds::sub::DataReader.

See SQL expression info
See State mask info in ReadCondition.

Parameters

query	The query to filter on the locally available data.
status	A mask, which selects only those samples with the desired sample/view/instance states.

Exceptions

dds::core::Exception

Definition at line 44 of file QueryConditionImpl.hpp.

QueryCondition() [2/6]

template<typename FUN >

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

Creates a QueryCondition instance.

This will create an QueryCondition that is associated with a dds::sub::Query, which is again associated with a dds::sub::DataReader.

The supplied functor will be called when this QueryCondition is triggered and either the inherited dds::core::cond::Condition::dispatch() is called or the dds::core::cond::WaitSet::dispatch() on the WaitSet to which this QueryCondition is attached to.

See SQL expression info
See State mask info in ReadCondition.

Parameters

query	The query to filter on the locally available data.
status	A mask, which selects only those samples with the desired sample/view/instance states.

Template Parameters

functor

The functor to be called when the QueryCondition triggers.

Exceptions

dds::core::Exception

QueryCondition() [3/6]

template<typename FUN >

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

Creates a QueryCondition instance.

This will create an QueryCondition that is associated with a dds::sub::Query, which is again associated with a dds::sub::DataReader.

The supplied functor will be called when this QueryCondition is triggered and either the inherited dds::core::cond::Condition::dispatch() is called or the dds::core::cond::WaitSet::dispatch() on the WaitSet to which this QueryCondition is attached to.

See SQL expression info
See State mask info in ReadCondition.

Parameters

query	The query to filter on the locally available data.
status	A mask, which selects only those samples with the desired sample/view/instance states.

Template Parameters

functor

The functor to be called when the QueryCondition triggers.

Exceptions

dds::core::Exception

QueryCondition() [4/6]

dds::sub::cond::QueryCondition::QueryCondition	(	const dds::sub::AnyDataReader &	dr,
		const std::string &	expression,
		const std::vector< std::string > &	params,
		const dds::sub::status::DataState &	status
	)

Creates a QueryCondition instance.

This will create an QueryCondition that is associated with an dds::sub::AnyDataReader, with parameters that essentially represent a query.

See SQL expression info
See State mask info in ReadCondition.

Parameters

dr	Query associated DataReader.
expression	Query expression
params	Query expression parameters
status	A mask, which selects only those samples with the desired sample/view/instance states.

Exceptions

dds::core::Exception

Definition at line 90 of file QueryConditionImpl.hpp.

QueryCondition() [5/6]

template<typename FUN >

dds::sub::cond::QueryCondition::QueryCondition	(	const dds::sub::AnyDataReader &	dr,
		const std::string &	expression,
		const std::vector< std::string > &	params,
		const dds::sub::status::DataState &	status,
		FUN &	functor
	)

Creates a QueryCondition instance.

This will create an QueryCondition that is associated with an dds::sub::AnyDataReader, with parameters that essentially represent a query.

The supplied functor will be called when this QueryCondition is triggered and either the inherited dds::core::cond::Condition::dispatch() is called or the dds::core::cond::WaitSet::dispatch() on the WaitSet to which this QueryCondition is attached to.

See SQL expression info
See State mask info in ReadCondition.

Parameters

dr	Query associated DataReader.
expression	Query expression
params	Query expression parameters
status	A mask, which selects only those samples with the desired sample/view/instance states.

Exceptions

dds::core::Exception

QueryCondition() [6/6]

template<typename FUN >

dds::sub::cond::QueryCondition::QueryCondition	(	const dds::sub::AnyDataReader &	dr,
		const std::string &	expression,
		const std::vector< std::string > &	params,
		const dds::sub::status::DataState &	status,
		const FUN &	functor
	)

Creates a QueryCondition instance.

This will create an QueryCondition that is associated with an dds::sub::AnyDataReader, with parameters that essentially represent a query.

The supplied functor will be called when this QueryCondition is triggered and either the inherited dds::core::cond::Condition::dispatch() is called or the dds::core::cond::WaitSet::dispatch() on the WaitSet to which this QueryCondition is attached to.

See SQL expression info
See State mask info in ReadCondition.

Parameters

dr	Query associated DataReader.
expression	Query expression
params	Query expression parameters
status	A mask, which selects only those samples with the desired sample/view/instance states.

Exceptions

dds::core::Exception

Member Function Documentation

add_parameter()

void dds::sub::cond::QueryCondition::add_parameter

(

const std::string &

param

)

Adds a parameter to the query.

See SQL expression info

Parameters

param

The parameter to add

Returns

void

Exceptions

dds::core::Exception

Definition at line 201 of file QueryConditionImpl.hpp.

begin() [1/2]

QueryCondition::const_iterator dds::sub::cond::QueryCondition::begin

(

)

const

Provides the beginning iterator of the query parameter list.

See SQL expression info

Returns

dds::sub::cond::QueryCondition::const_iterator The beginning iterator

Exceptions

dds::core::Exception

Definition at line 171 of file QueryConditionImpl.hpp.

begin() [2/2]

QueryCondition::iterator dds::sub::cond::QueryCondition::begin

(

)

Provides the beginning iterator of the query parameter list.

See SQL expression info

Returns

dds::sub::cond::QueryCondition::iterator The beginning iterator

Exceptions

dds::core::Exception

Definition at line 187 of file QueryConditionImpl.hpp.

data_reader()

const AnyDataReader & dds::sub::cond::QueryCondition::data_reader

(

)

const

This operation returns the DataReader associated with the QueryCondition.

Note that there is exactly one DataReader associated with each QueryCondition.

Returns

dds::sub::AnyDataReader The associated DataReader

Exceptions

dds::core::Exception

Definition at line 218 of file QueryConditionImpl.hpp.

dispatch()

void dds::core::cond::Condition::dispatch ( )

inherited

Dispatches the functor that have been registered with the Condition.

The Condition has to have been triggered for the functor will be called by this function.

Returns

void

Exceptions

dds::core::Exception

Definition at line 76 of file ConditionImpl.hpp.

end() [1/2]

QueryCondition::const_iterator dds::sub::cond::QueryCondition::end

(

)

const

Provides the end iterator of the query parameter list.

See SQL expression info

Returns

dds::sub::cond::QueryCondition::const_iterator The end iterator

Exceptions

dds::core::Exception

Definition at line 179 of file QueryConditionImpl.hpp.

end() [2/2]

QueryCondition::iterator dds::sub::cond::QueryCondition::end

(

)

Provides the end iterator of the query parameter list.

See SQL expression info

Returns

dds::sub::cond::QueryCondition::iterator The end iterator

Exceptions

dds::core::Exception

Definition at line 193 of file QueryConditionImpl.hpp.

expression() [1/3]

const std::string & dds::sub::Query::expression ( ) const

inherited

Get expression.

Returns

std::string The SQL expression.

Exceptions

dds::core::Exception

Definition at line 70 of file QueryImpl.hpp.

expression() [2/3]

void dds::sub::cond::QueryCondition::expression

(

const std::string &

expr

)

Set the Query expression.

Parameters

expr	SQL expression

Returns

void

Exceptions

dds::core::Exception

Definition at line 154 of file QueryConditionImpl.hpp.

expression() [3/3]

const std::string & dds::sub::cond::QueryCondition::expression

(

)

Get the Query expression.

See SQL expression info

Returns

std::string The query expression

Exceptions

dds::core::Exception

Definition at line 163 of file QueryConditionImpl.hpp.

handler() [1/2]

template<typename Functor >

void dds::core::cond::Condition::handler ( Functor &  func )

inherited

Registers a functor as custom handler with this Condition.

The supplied functor will be called when this Condition is triggered and either the dds::core::cond::Condition::dispatch() is called or the dds::core::cond::WaitSet::dispatch() on the WaitSet to which this Condition is attached to.

Template Parameters

Functor

The functor to be called when the StatusCondition triggers.

Returns

void

Exceptions

dds::core::Exception

handler() [2/2]

template<typename Functor >

void dds::core::cond::Condition::handler ( const Functor &  func )

inherited

Registers a functor as custom handler with this Condition.

The supplied functor will be called when this Condition is triggered and either the dds::core::cond::Condition::dispatch() is called or the dds::core::cond::WaitSet::dispatch() on the WaitSet to which this Condition is attached to.

Template Parameters

Functor

The functor to be called when the StatusCondition triggers.

Returns

void

Exceptions

dds::core::Exception

is_nil()

template<typename DELEGATE >

bool dds::core::Reference< DELEGATE >::is_nil ( ) const

inherited

Check if the referenced object is nil.

In other words, check if the reference is pointing to a null object.

Returns

true if the referenced object is null.

Definition at line 143 of file ReferenceImpl.hpp.

operator!=() [1/2]

template<typename DELEGATE >

template<typename R >

bool dds::core::Reference< DELEGATE >::operator!= ( const R &  ref ) const

inherited

Compares two Reference objects and returns true if they are not equal.

Inequality is based on the referential inequality of the object being pointed to.

Parameters

ref	the other Reference object

Returns

true when not equal

Definition at line 100 of file ReferenceImpl.hpp.

operator!=() [2/2]

template<typename DELEGATE >

bool dds::core::Reference< DELEGATE >::operator!= ( const null_type  nil ) const

inherited

Special operator!= used to check if this reference object does not equal the dds::core::null reference.

The non-null-check can be done like this:

if (r != dds::core::null) {
   // Use the dds reference object r
}

Returns

true if this reference is not null.

Definition at line 157 of file ReferenceImpl.hpp.

operator->() [1/2]

template<typename DELEGATE >

DELEGATE * dds::core::Reference< DELEGATE >::operator-> ( )

inherited

The operator->() is provided to be able to directly invoke functions on the delegate.

The decision to provide direct access to the delegate was motivated by the need for providing a way that was not invasive with respect to the CXXDDS API and yet would allow for vendor-specific extension. Thus vendor-specific extensions can be invoked on the Reference and on all its subclasses as follows:

my_dds_entity.standard_function();
my_dds_entity->vendor_specific_extension();

Returns

a reference to delegate.

Definition at line 180 of file ReferenceImpl.hpp.

operator->() [2/2]

template<typename DELEGATE >

const DELEGATE * dds::core::Reference< DELEGATE >::operator-> ( ) const

inherited

The operator->() is provided to be able to directly invoke functions on the delegate.

The decision to provide direct access to the delegate was motivated by the need for providing a way that was not invasive with respect to the CXXDDS API and yet would allow for vendor-specific extension. Thus vendor-specific extensions can be invoked on the Reference and on all its subclasses as follows:

my_dds_entity.standard_function();
my_dds_entity->vendor_specific_extension();

Returns

a reference to delegate.

Definition at line 188 of file ReferenceImpl.hpp.

operator==() [1/2]

template<typename DELEGATE >

template<typename R >

bool dds::core::Reference< DELEGATE >::operator== ( const R &  ref ) const

inherited

Compares two Reference objects and returns true if they are equal.

Equality is based on the referential equality of the object being pointed.

Parameters

ref	the other Reference object

Returns

true when equal

Definition at line 83 of file ReferenceImpl.hpp.

operator==() [2/2]

template<typename DELEGATE >

bool dds::core::Reference< DELEGATE >::operator== ( const null_type  ) const

inherited

Special operator== used to check if this reference object equals the dds::core::null reference.

The null-check can be done like this:

if (r == dds::core::null) {
   // Do not use the dds reference object r in its current state
}

Returns

true if this reference is null.

Definition at line 150 of file ReferenceImpl.hpp.

parameters()

template<typename FWIterator >

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

Sets the query parameters.

See SQL expression info

Template Parameters

begin	Iterator pointing to the beginning of the parameters to set
end	Iterator pointing to the end of the parameters to set

Returns

void

Exceptions

dds::core::Exception

Definition at line 145 of file QueryConditionImpl.hpp.

parameters_length()

uint32_t dds::sub::cond::QueryCondition::parameters_length

(

)

const

Gets the number of parameters in the query.

See SQL expression info

Returns

uint32_t The number of parameters in the query

Exceptions

dds::core::Exception

Definition at line 210 of file QueryConditionImpl.hpp.

reset_handler()

void dds::core::cond::Condition::reset_handler ( )

inherited

Resets the handler for this Condition.

After the invocation of this function no handler will be registered with this Condition.

Returns

void

Exceptions

dds::core::Exception

Definition at line 69 of file ConditionImpl.hpp.

state_filter()

const dds::sub::status::DataState dds::sub::cond::ReadCondition::state_filter ( ) const

inherited

This operation returns the set of data-states that are taken into account to determine the trigger_value of the ReadCondition.

These are data-states specified when the ReadCondition was created.

Returns

dds::sub::status::DataState The data state.

Exceptions

dds::core::Exception

Definition at line 87 of file ReadConditionImpl.hpp.

trigger_value()

bool dds::core::cond::Condition::trigger_value ( ) const

inherited

This operation retrieves the trigger_value of the Condition.

A Condition has a trigger_value that can be TRUE or FALSE and is set by the Data Distribution Service (except a GuardCondition). This operation returns the trigger_value of the Condition.

Returns

bool The boolean value to which the Condition is set.

Exceptions

dds::core::Exception

Definition at line 83 of file ConditionImpl.hpp.

---

The documentation for this class was generated from the following files:

• include/dcps/C++/isocpp2/dds/sub/cond/QueryCondition.hpp
• include/dcps/C++/isocpp2/dds/sub/cond/detail/QueryConditionImpl.hpp