QXmppTask< T > Class Template Reference

#include <QXmppTask.h>

Public Member Functions
void	then (const QObject *context, Continuation continuation)
bool	isFinished () const
bool	hasResult () const
const T &	result () const
T	takeResult ()
QFuture< T >	toFuture (const QObject *context)

Friends
class	QXmppPromise< T >

Detailed Description

template<typename T>
class QXmppTask< T >

Handle for an ongoing operation that finishes in the future.

Tasks are generated by QXmppPromise and can be handled using QXmppTask::then().

Unlike QFuture, this is not thread-safe!! This avoids the need to do mutex locking at every access though.

Since

QXmpp 1.5

Member Function Documentation

hasResult()

template<typename T >

bool QXmppTask< T >::hasResult ( ) const

inline

Returns whether the task is finished and the value has not been taken yet.

isFinished()

template<typename T >

bool QXmppTask< T >::isFinished ( ) const

inline

Whether the asynchronous operation is already finished.

This does not mean that the result is still stored, it might have been taken using takeResult() or handled using then().

result()

template<typename T >

const T & QXmppTask< T >::result ( ) const

inline

The result of the operation.

Warning

This can only be used once the operation is finished.

takeResult()

template<typename T >

T QXmppTask< T >::takeResult ( )

inline

Moves the result of the operation out of the task.

Warning

This can only be used once and only after the operation has finished.

then()

template<typename T >

void QXmppTask< T >::then ( const QObject *  context, Continuation  continuation  )

inline

Registers a function that will be called with the result as parameter when the asynchronous operation finishes.

If the task is already finished when calling this (and still has a result), the function will be called immediately.

.then() can be called multiple times if and only if T is copy-constructible. For copyable types all continuations will be called in the order they were set. For move-only types only the latest continuation will be called.

Example usage:

QXmppTask<QString> generateSomething();
 
void Manager::generate()
{
    generateSomething().then(this, [](QString &&result) {
        // runs as soon as the result is finished
        qDebug() << "Generating finished:" << result;
    });
 
    // The generation could still be in progress here and the lambda might not
    // have been executed yet.
}
 
// Manager is derived from QObject.

Note

Support for multiple continuations with copy-constructible types was added in QXmpp 1.11.

Parameters

context	QObject used for unregistering the handler function when the object is deleted. This way your lambda will never be executed after your object has been deleted.
continuation	A function accepting a result in the form of T &&.

toFuture()

template<typename T >

QFuture< T > QXmppTask< T >::toFuture ( const QObject *  context )

inline

Converts the Task into a QFuture. Afterwards the QXmppTask object is invalid.

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

• QXmppTask.h