dds::sub::LoanedSamples< T > Class Template Reference

<<move-only-type>> Provides temporary access to a collection of samples from a DataReader. More...

#include <LoanedSamplesImpl.hpp>

Public Types
typedef SampleIterator< T >	iterator
	The iterator type.

Public Member Functions
	LoanedSamples ()
	Creates an empty LoanedSamples object.
	~LoanedSamples () throw ()
	Automatically returns the loan to the DataReader.
value_type	operator[] (size_t index)
	Provides access to the underlying LoanedSample object in array-like syntax.
unsigned int	length () const
	Gets the number of samples in this collection.
void	return_loan ()
	Returns the samples to the container // TODO.
iterator	begin ()
	Gets an iterator to the first sample.
iterator	end ()
	Gets an iterator to one past the last sample.
const_iterator	begin () const
	Gets an iterator to the first sample.
const_iterator	end () const
	Gets an iterator to one past the last sample.
void	swap (LoanedSamples &other) throw ()
	Swap two LoanedSamples containers.
	LoanedSamples (LoanedSamples &&other)
	<<C++11>> Moves the loan from an existing LoanedSamples to a new one

Related Functions
(Note that these are not member functions.)
template<typename T >
LoanedSamples< T >	move (LoanedSamples< T > &ls) OMG_NOEXCEPT
	Creates a new LoanedSamples instance by moving the contents of an existing one.
template<typename T >
LoanedSamples< T >::iterator	begin (LoanedSamples< T > &ls)
template<typename T >
LoanedSamples< T >::const_iterator	begin (const LoanedSamples< T > &ls)
template<typename T >
LoanedSamples< T >::iterator	end (LoanedSamples< T > &ls)
template<typename T >
LoanedSamples< T >::const_iterator	end (const LoanedSamples< T > &ls)
template<typename T >
void	swap (LoanedSamples< T > &ls1, LoanedSamples< T > &ls2) throw()
template<typename T >
ValidSampleIterator< T >	valid_samples (const SampleIterator< T > &sample_iterator)
	<<extension>> Returns an iterator that skips invalid samples

Detailed Description

template<typename T>
class dds::sub::LoanedSamples< T >

<<move-only-type>> Provides temporary access to a collection of samples from a DataReader.

Template Parameters

T	The topic-type. It has to match the type of the DataReader.

This STL-like container encapsulates a collection of loaned, read-only data samples from a DataReader.

To obtain a LoanedSamples you need to call one of the read/take operations from a DataReader. The samples have to be eventually returned to the DataReader. The destructor takes care of that, and the return_loan() function lets you do it explicitly if needed.

As a move-only type copying a LoanedSamples is not allowed. If you want to have more than one reference to a collection of loaned sample, see SharedSamples. If you need to return a LoanedSamples from a function or assign it to another variable, use dds::core::move() (or std::move() <<C++11>>).

Iterators and overloaded subscript operators let you access the samples in this container, which are of the type rti::sub::LoanedSample.

See Also

Reading data samples

Examples:

Foo_subscriber.cxx.

Member Typedef Documentation

template<typename T>

typedef SampleIterator<T> dds::sub::LoanedSamples< T >::iterator

The iterator type.

Constructor & Destructor Documentation

template<typename T>

dds::sub::LoanedSamples< T >::LoanedSamples ( )

inline

Creates an empty LoanedSamples object.

template<typename T>

dds::sub::LoanedSamples< T >::~LoanedSamples ( ) throw ()

inline

Automatically returns the loan to the DataReader.

See Also

return_loan

template<typename T>

dds::sub::LoanedSamples< T >::LoanedSamples ( LoanedSamples< T > &&  other )

inline

<<C++11>> Moves the loan from an existing LoanedSamples to a new one

Member Function Documentation

template<typename T>

value_type dds::sub::LoanedSamples< T >::operator[] ( size_t  index )

inline

Provides access to the underlying LoanedSample object in array-like syntax.

Parameters

index

The index of the Sample. Allowed values are from 0 to length()-1.

Returns

A LoanedSample object that refers to data and SampleInfo at the specified index.

template<typename T>

unsigned int dds::sub::LoanedSamples< T >::length ( ) const

inline

Gets the number of samples in this collection.

template<typename T>

void dds::sub::LoanedSamples< T >::return_loan ( )

inline

Returns the samples to the container // TODO.

template<typename T>

iterator dds::sub::LoanedSamples< T >::begin ( )

inline

Gets an iterator to the first sample.

template<typename T>

iterator dds::sub::LoanedSamples< T >::end ( )

inline

Gets an iterator to one past the last sample.

template<typename T>

const_iterator dds::sub::LoanedSamples< T >::begin ( ) const

inline

Gets an iterator to the first sample.

template<typename T>

const_iterator dds::sub::LoanedSamples< T >::end ( ) const

inline

Gets an iterator to one past the last sample.

template<typename T>

void dds::sub::LoanedSamples< T >::swap ( LoanedSamples< T > &  other ) throw ()

inline

Swap two LoanedSamples containers.

Friends And Related Function Documentation

template<typename T >

LoanedSamples< T > move ( LoanedSamples< T > &  ls )

related

Creates a new LoanedSamples instance by moving the contents of an existing one.

Note: in <<C++11>> you can directly use std::move.

The parameter object loses the ownership of the underlying samples and its state is reset as if it was default initialized. This function must be used to move any named LoanedSamples instance (lvalue) in and out of a function by-value. Using this function is not necessary if the original LoanedSamples is an rvalue. Moving is a very efficient operation and is guaranteed to not throw any exception.

Parameters

ls	The LoanedSamples object that transfers its ownership of the contained samples into the returned object. After this call, ls is empty.

Returns

A new LoanedSamples object, the new loan owner, with the same contents as ls had.

See Also

LoanedSamples

template<typename T >

LoanedSamples< T >::iterator begin ( LoanedSamples< T > &  ls )

related

See Also

LoanedSamples::begin()

template<typename T >

LoanedSamples< T >::const_iterator begin ( const LoanedSamples< T > &  ls )

related

See Also

LoanedSamples::begin()

template<typename T >

LoanedSamples< T >::iterator end ( LoanedSamples< T > &  ls )

related

See Also

LoanedSamples::end()

template<typename T >

LoanedSamples< T >::const_iterator end ( const LoanedSamples< T > &  ls )

related

See Also

LoanedSamples::end()

template<typename T >

void swap ( LoanedSamples< T > &  ls1, LoanedSamples< T > &  ls2  ) throw()

related

See Also

LoanedSamples::swap()

template<typename T >

ValidSampleIterator< T > valid_samples ( const SampleIterator< T > &  sample_iterator )

related

<<extension>> Returns an iterator that skips invalid samples

Given a regular sample iterator, this functions creates another iterator it that behaves exactly the same except that it++ moves to the next valid sample (or to the end of the collection). That is, if it doesn't point to the end of the collection, it->info.valid() is always true.

This is useful when your application doesn't need to deal with samples containing meta-information only.

For example, the following code copies all the data in a LoanedSamples collection skipping any invalid samples (otherwise, attempting to copy the data from an invalid sample would throw an exception, see rti::sub::LoanedSample::operator const DataType& ()).

dds::sub::LoanedSamples<KeyedType> samples = reader.take();
std::vector<KeyedType> data_vector;
std::copy(
     rti::sub::valid_samples(samples.begin()),
     rti::sub::valid_samples(samples.end()),
     std::back_inserter(data_vector));

Note that valid_samples(samples.begin()) won't point to the first element if that element is not a valid sample.

A similar utility is the functor rti::sub::IsValidData.

See Also

dds::sub::LoanedSamples

rti::sub::IsValidData

dds::sub::SampleInfo::valid()

Reading data samples