Query objects contain expressions that allow the application to specify a filter on the locally available data. More...

#include "Query.hpp"

Inheritance diagram for dds::sub::Query:

Public Types
typedef DELEGATE::const_iterator	const_iterator

typedef DELEGATE::iterator	iterator

Public Member Functions
	Query (const dds::sub::AnyDataReader &dr, const std::string &expression)

template<typename FWIterator >
	Query (const dds::sub::AnyDataReader &dr, const std::string &expression, const FWIterator &params_begin, const FWIterator &params_end)

	Query (const dds::sub::AnyDataReader &dr, const std::string &expression, const std::vector< std::string > &params)

void	add_parameter (const std::string &param)

const_iterator	begin () const

iterator	begin ()

const AnyDataReader &	data_reader () const

const_iterator	end () const

iterator	end ()

const std::string &	expression () const

void	expression (const std::string &expr)

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

Detailed Description

Query objects contain expressions that allow the application to specify a filter on the locally available data.

A Query is used in a QueryCondition or DataReader::Selector and is associated with one DataReader.

SQL Expression: The SQL query string is set by expression which must be a subset of the SQL query language. In this query expression, parameters may be used, which must be set in the sequence of strings defined by the parameter query_parameters. A parameter is a string which can define an integer, float, string or enumeration. The number of values in query_parameters must be equal or greater than the highest referenced n token in the query_expression (e.g. if %1 and %8 are used as parameters in the query_expression, the query_parameters should at least contain n+1 = 9 values).
Look here for the specific query expression syntax.

See also: dds::sub::cond::QueryCondition; dds::sub::DataReader::Selector; dds::sub::DataReader::ManipulatorSelector; Subscription concept

Definition at line 61 of file Query.hpp.

Member Typedef Documentation

◆ const_iterator

typedef DELEGATE::const_iterator dds::sub::Query::const_iterator

Iterator for the query expression parameters.

Definition at line 75 of file Query.hpp.

◆ iterator

typedef DELEGATE::iterator dds::sub::Query::iterator

Iterator for the query expression parameters.

Definition at line 70 of file Query.hpp.

Constructor & Destructor Documentation

◆ Query() [1/3]

dds::sub::Query::Query	(	const dds::sub::AnyDataReader &	dr,
		const std::string &	expression
	)

Create a dds::sub::Query associated with an dds::sub::AnyDataReader.

Parameters

dr	The AnyDataReader to associate with the Query.
expression	SQL expression

Exceptions

dds::core::Exception

Definition at line 32 of file QueryImpl.hpp.

◆ Query() [2/3]

template<typename FWIterator >

dds::sub::Query::Query	(	const dds::sub::AnyDataReader &	dr,
		const std::string &	expression,
		const FWIterator &	params_begin,
		const FWIterator &	params_end
	)

Create a dds::sub::Query associated with an dds::sub::AnyDataReader.

Parameters

dr	The AnyDataReader to associate with the Query.
expression	SQL expression

Template Parameters

params_begin	Iterator pointing to the beginning of the parameters to set
params_end	Iterator pointing to the end of the parameters to set

Exceptions

dds::core::Exception

◆ Query() [3/3]

dds::sub::Query::Query	(	const dds::sub::AnyDataReader &	dr,
		const std::string &	expression,
		const std::vector< std::string > &	params
	)

Create a dds::sub::Query associated with an dds::sub::AnyDataReader.

Parameters

dr	The AnyDataReader to associate with the Query.
expression	SQL expression

Template Parameters

params Vector containing SQL expression parameters

Exceptions

dds::core::Exception

Definition at line 60 of file QueryImpl.hpp.

Member Function Documentation

◆ add_parameter()

void dds::sub::Query::add_parameter ( const std::string & param )

Adds a parameter to the query.

See SQL expression info

Parameters

param The parameter to add

Exceptions

dds::core::Exception

Definition at line 147 of file QueryImpl.hpp.

◆ begin() [1/2]

dds::sub::Query::const_iterator dds::sub::Query::begin ( ) const

Provides the begin iterator to the SQL expression parameter list.

See SQL expression info

Returns: dds::sub::Query::const_iterator The begin iterator

Exceptions

dds::core::Exception Provides the begin iterator to the parameter list.

Definition at line 89 of file QueryImpl.hpp.

◆ begin() [2/2]

dds::sub::Query::iterator dds::sub::Query::begin ( )

Provides the begin iterator to the SQL expression parameter list.

See SQL expression info

Returns: dds::sub::Query::iterator The begin iterator

Exceptions

dds::core::Exception Provides the begin iterator to the parameter list.

Definition at line 111 of file QueryImpl.hpp.

◆ data_reader()

const dds::sub::AnyDataReader & dds::sub::Query::data_reader ( ) const

This operation returns the DataReader associated with the Query.

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

Returns: dds::sub::AnyDataReader The associated DataReader

Exceptions

dds::core::Exception

Definition at line 165 of file QueryImpl.hpp.

◆ end() [1/2]

dds::sub::Query::const_iterator dds::sub::Query::end ( ) const

The end iterator to the SQL expression parameter list.

See SQL expression info

Returns: dds::sub::Query::const_iterator The end iterator

Exceptions

dds::core::Exception The end iterator to the parameter list.

Definition at line 100 of file QueryImpl.hpp.

◆ end() [2/2]

dds::sub::Query::iterator dds::sub::Query::end ( )

The end iterator to the SQL expression parameter list.

See SQL expression info

Returns: dds::sub::Query::iterator The end iterator

Exceptions

dds::core::Exception The end iterator to the parameter list.

Definition at line 122 of file QueryImpl.hpp.

◆ expression() [1/2]

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

Get expression.

Returns: std::string The SQL expression.

Exceptions

dds::core::Exception

Definition at line 70 of file QueryImpl.hpp.

◆ expression() [2/2]

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

Set new expression.

Parameters

expr	ref anchor_dds_sub_query_expression "SQL expression"

Exceptions

dds::core::Exception

Definition at line 78 of file QueryImpl.hpp.

◆ 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::Query::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

Exceptions

dds::core::Exception

Definition at line 131 of file QueryImpl.hpp.

◆ parameters_length()

uint32_t dds::sub::Query::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 156 of file QueryImpl.hpp.

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

include/dcps/C++/isocpp2/dds/sub/Query.hpp
include/dcps/C++/isocpp2/dds/sub/detail/QueryImpl.hpp

Public Types

Public Member Functions

Detailed Description

Member Typedef Documentation

◆ const_iterator

◆ iterator

Constructor & Destructor Documentation

◆ Query() [1/3]

◆ Query() [2/3]

◆ Query() [3/3]

Member Function Documentation

◆ add_parameter()

◆ begin() [1/2]

◆ begin() [2/2]

◆ data_reader()

◆ end() [1/2]

◆ end() [2/2]

◆ expression() [1/2]

◆ expression() [2/2]

◆ is_nil()

◆ operator!=() [1/2]

◆ operator!=() [2/2]

◆ operator->() [1/2]

◆ operator->() [2/2]

◆ operator==() [1/2]

◆ operator==() [2/2]

◆ parameters()

◆ parameters_length()