ThreadWeaver::Queue

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#include <queue.h>

Inheritance diagram for ThreadWeaver::Queue:

Classes

struct  GlobalQueueFactory
 

Public Member Functions

 Queue (QObject *parent=nullptr)
 
 Queue (QueueSignals *implementation, QObject *parent=nullptr)
 
 ~Queue () override
 
int currentNumberOfThreads () const override
 
void dequeue () override
 
bool dequeue (const JobPointer &) override
 
void enqueue (const JobPointer &job)
 
void enqueue (const QVector< JobPointer > &jobs) override
 
void finish () override
 
bool isEmpty () const override
 
bool isIdle () const override
 
int maximumNumberOfThreads () const override
 
int queueLength () const override
 
void requestAbort () override
 
void reschedule () override
 
void resume () override
 
void setMaximumNumberOfThreads (int cap) override
 
void shutDown () override
 
const Statestate () const override
 
QueueStream stream ()
 
void suspend () override
 
- Public Member Functions inherited from ThreadWeaver::QueueSignals
 QueueSignals (QObject *parent=nullptr)
 
 QueueSignals (ThreadWeaver::Private::QueueSignals_Private *d, QObject *parent=nullptr)
 
- Public Member Functions inherited from QObject
 QObject (QObject *parent)
 
bool blockSignals (bool block)
 
const QObjectListchildren () const const
 
QMetaObject::Connection connect (const QObject *sender, const char *signal, const char *method, Qt::ConnectionType type) const const
 
void deleteLater ()
 
void destroyed (QObject *obj)
 
bool disconnect (const char *signal, const QObject *receiver, const char *method) const const
 
bool disconnect (const QObject *receiver, const char *method) const const
 
void dumpObjectInfo ()
 
void dumpObjectInfo () const const
 
void dumpObjectTree ()
 
void dumpObjectTree () const const
 
QList< QByteArraydynamicPropertyNames () const const
 
virtual bool event (QEvent *e)
 
virtual bool eventFilter (QObject *watched, QEvent *event)
 
findChild (const QString &name, Qt::FindChildOptions options) const const
 
QList< T > findChildren (const QRegExp &regExp, Qt::FindChildOptions options) const const
 
QList< T > findChildren (const QRegularExpression &re, Qt::FindChildOptions options) const const
 
QList< T > findChildren (const QString &name, Qt::FindChildOptions options) const const
 
bool inherits (const char *className) const const
 
void installEventFilter (QObject *filterObj)
 
bool isWidgetType () const const
 
bool isWindowType () const const
 
void killTimer (int id)
 
virtual const QMetaObjectmetaObject () const const
 
void moveToThread (QThread *targetThread)
 
QString objectName () const const
 
void objectNameChanged (const QString &objectName)
 
QObjectparent () const const
 
QVariant property (const char *name) const const
 
 Q_CLASSINFO (Name, Value)
 
 Q_DISABLE_COPY (Class)
 
 Q_DISABLE_COPY_MOVE (Class)
 
 Q_DISABLE_MOVE (Class)
 
 Q_EMIT Q_EMIT
 
 Q_ENUM (...)
 
 Q_ENUM_NS (...)
 
 Q_ENUMS (...)
 
 Q_FLAG (...)
 
 Q_FLAG_NS (...)
 
 Q_FLAGS (...)
 
 Q_GADGET Q_GADGET
 
 Q_INTERFACES (...)
 
 Q_INVOKABLE Q_INVOKABLE
 
 Q_NAMESPACE Q_NAMESPACE
 
 Q_NAMESPACE_EXPORT (EXPORT_MACRO)
 
 Q_OBJECT Q_OBJECT
 
 Q_PROPERTY (...)
 
 Q_REVISION Q_REVISION
 
 Q_SET_OBJECT_NAME (Object)
 
 Q_SIGNAL Q_SIGNAL
 
 Q_SIGNALS Q_SIGNALS
 
 Q_SLOT Q_SLOT
 
 Q_SLOTS Q_SLOTS
 
qFindChild (const QObject *obj, const QString &name)
 
QList< T > qFindChildren (const QObject *obj, const QRegExp &regExp)
 
QList< T > qFindChildren (const QObject *obj, const QString &name)
 
qobject_cast (const QObject *object)
 
qobject_cast (QObject *object)
 
 QT_NO_NARROWING_CONVERSIONS_IN_CONNECT QT_NO_NARROWING_CONVERSIONS_IN_CONNECT
 
void removeEventFilter (QObject *obj)
 
void setObjectName (const QString &name)
 
void setParent (QObject *parent)
 
bool setProperty (const char *name, const QVariant &value)
 
bool signalsBlocked () const const
 
int startTimer (int interval, Qt::TimerType timerType)
 
int startTimer (std::chrono::milliseconds time, Qt::TimerType timerType)
 
QThreadthread () const const
 

Static Public Member Functions

static ThreadWeaver::Queueinstance ()
 
static void setGlobalQueueFactory (GlobalQueueFactory *factory)
 
- Static Public Member Functions inherited from QObject
QMetaObject::Connection connect (const QObject *sender, const char *signal, const QObject *receiver, const char *method, Qt::ConnectionType type)
 
QMetaObject::Connection connect (const QObject *sender, const QMetaMethod &signal, const QObject *receiver, const QMetaMethod &method, Qt::ConnectionType type)
 
QMetaObject::Connection connect (const QObject *sender, PointerToMemberFunction signal, const QObject *context, Functor functor, Qt::ConnectionType type)
 
QMetaObject::Connection connect (const QObject *sender, PointerToMemberFunction signal, const QObject *receiver, PointerToMemberFunction method, Qt::ConnectionType type)
 
QMetaObject::Connection connect (const QObject *sender, PointerToMemberFunction signal, Functor functor)
 
bool disconnect (const QMetaObject::Connection &connection)
 
bool disconnect (const QObject *sender, const char *signal, const QObject *receiver, const char *method)
 
bool disconnect (const QObject *sender, const QMetaMethod &signal, const QObject *receiver, const QMetaMethod &method)
 
bool disconnect (const QObject *sender, PointerToMemberFunction signal, const QObject *receiver, PointerToMemberFunction method)
 
QString tr (const char *sourceText, const char *disambiguation, int n)
 
QString trUtf8 (const char *sourceText, const char *disambiguation, int n)
 

Additional Inherited Members

- Properties inherited from QObject
 objectName
 
- Signals inherited from ThreadWeaver::QueueSignals
void finished ()
 
void stateChanged (ThreadWeaver::State *)
 
void suspended ()
 
- Public Attributes inherited from QObject
typedef QObjectList
 
- Protected Member Functions inherited from ThreadWeaver::QueueSignals
ThreadWeaver::Private::QueueSignals_Private * d ()
 
const ThreadWeaver::Private::QueueSignals_Private * d () const
 
- Protected Member Functions inherited from QObject
virtual void childEvent (QChildEvent *event)
 
virtual void connectNotify (const QMetaMethod &signal)
 
virtual void customEvent (QEvent *event)
 
virtual void disconnectNotify (const QMetaMethod &signal)
 
bool isSignalConnected (const QMetaMethod &signal) const const
 
int receivers (const char *signal) const const
 
QObjectsender () const const
 
int senderSignalIndex () const const
 
virtual void timerEvent (QTimerEvent *event)
 

Detailed Description

Queue implements a ThreadWeaver job queue.

Queues process jobs enqueued in them by automatically assigning them to worker threads they manage. Applications using ThreadWeaver can make use of a global Queue which is instantiated on demand, or create multiple queues as needed. A job assigned to a queue will be processed by that specific queue.

Worker threads are created by the queues as needed. To create a customized global queue, see GlobalQueueFactory.

See also
GlobalQueueFactory
Queue::enqueue()
Queue::instance()

Definition at line 35 of file queue.h.

Constructor & Destructor Documentation

◆ Queue() [1/2]

Queue::Queue ( QObject parent = nullptr)
explicit

Construct a Queue.

Definition at line 41 of file queue.cpp.

◆ Queue() [2/2]

Queue::Queue ( QueueSignals implementation,
QObject parent = nullptr 
)
explicit

Construct a queue with a customized implementation The queue takes ownership and will delete the implementation upon destruction.

Construct a Queue, specifying the QueueSignals implementation to use.

The QueueSignals instance is usually a Weaver object, which may be customized for specific application needs. The Weaver instance will take ownership of the implementation object and deletes it when destructed.

See also
Weaver
GlobalQueueFactory

Definition at line 55 of file queue.cpp.

◆ ~Queue()

Queue::~Queue ( )
override

Destruct the Queue object.

If the queue is not already in Destructed state, the destructor will call shutDown() to make sure enqueued jobs are completed and the queue is idle. The queue implementation will be destroyed.

See also
shutDown()
ThreadWeaver::Destructed

Definition at line 69 of file queue.cpp.

Member Function Documentation

◆ currentNumberOfThreads()

int Queue::currentNumberOfThreads ( ) const
overridevirtual

Returns the current number of threads in the inventory.

Implements ThreadWeaver::QueueInterface.

Definition at line 222 of file queue.cpp.

◆ dequeue() [1/2]

void Queue::dequeue ( )
overridevirtual

Remove all queued jobs.

All waiting jobs will be dequeued. The semantics are the same as for dequeue(JobInterface).

See also
dequeue(JobInterface)

Implements ThreadWeaver::QueueInterface.

Definition at line 182 of file queue.cpp.

◆ dequeue() [2/2]

bool Queue::dequeue ( const JobPointer job)
overridevirtual

Remove a job from the queue.

If the job was queued but not started so far, it is removed from the queue.

You can always call dequeue, it will return true if the job was dequeued. However if the job is not in the queue anymore, it is already being executed, it is too late to dequeue, and dequeue will return false. The return value is thread-safe - if true is returned, the job was still waiting, and has been dequeued. If not, the job was not waiting in the queue.

Modifying queued jobs is best done on a suspended queue. Often, for example at the end of an application, it is sufficient to dequeue all jobs (which leaves only the ones mid-air in threads), call finish (that will wait for all the mid air jobs to complete), and then exit. Without dequeue(), all jobs in the queue would be executed during finish().

See also
requestAbort for aborting jobs during execution
Returns
true if the job was waiting and has been dequeued
false if the job was not found waiting in the queue

Implements ThreadWeaver::QueueInterface.

Definition at line 177 of file queue.cpp.

◆ enqueue()

void Queue::enqueue ( const QVector< JobPointer > &  jobs)
overridevirtual

Queue a vector of jobs.

It depends on the state if execution of the job will be attempted immediately. In suspended state, jobs can be added to the queue, but the threads remain suspended. In WorkongHard state, an idle thread may immediately execute the job, or it might be queued if all threads are busy.

JobPointer is a shared pointer. This means the object pointed to will be deleted if this object is the last remaining reference to it. Keep a JobPointer to the job to avoid automatic deletion.

Implements ThreadWeaver::QueueInterface.

Definition at line 167 of file queue.cpp.

◆ finish()

void Queue::finish ( )
overridevirtual

Finish all queued operations, then return.

This method is used in imperative (not event driven) programs that cannot react on events to have the controlling (main) thread wait wait for the jobs to finish. The call will block the calling thread and return when all queued jobs have been processed.

Warning: This will suspend your thread! Warning: If one of your jobs enters an infinite loop, this will never return!

Implements ThreadWeaver::QueueInterface.

Definition at line 187 of file queue.cpp.

◆ instance()

Queue * Queue::instance ( )
static

Access the application-global Queue.

In some cases, the global queue is sufficient for the applications purpose. The global queue will only be created if this method is actually called in the lifetime of the application.

The Q(Core)Application object must exist when instance() is called for the first time. The global queue will be destroyed when Q(Core)Application is destructed. After that, the instance() method returns zero.

Definition at line 152 of file queue.cpp.

◆ isEmpty()

bool Queue::isEmpty ( ) const
overridevirtual

Is the queue empty? The queue is empty if no more jobs are queued.

Implements ThreadWeaver::QueueInterface.

Definition at line 202 of file queue.cpp.

◆ isIdle()

bool Queue::isIdle ( ) const
overridevirtual

Is the weaver idle? The weaver is idle if no jobs are queued and no jobs are processed by the threads.

Implements ThreadWeaver::QueueInterface.

Definition at line 207 of file queue.cpp.

◆ maximumNumberOfThreads()

int Queue::maximumNumberOfThreads ( ) const
overridevirtual

Get the maximum number of threads this Weaver may start.

Implements ThreadWeaver::QueueInterface.

Definition at line 227 of file queue.cpp.

◆ queueLength()

int Queue::queueLength ( ) const
overridevirtual

Returns the number of pending jobs.

This will return the number of queued jobs. Jobs that are currently being executed are not part of the queue. All jobs in the queue are waiting to be executed.

Implements ThreadWeaver::QueueInterface.

Definition at line 212 of file queue.cpp.

◆ requestAbort()

void Queue::requestAbort ( )
overridevirtual

Request aborts of the currently executed jobs.

It is important to understand that aborts are requested, but cannot be guaranteed, as not all Job classes support it. It is up to the application to decide if and how job aborts are necessary.

Implements ThreadWeaver::QueueInterface.

Definition at line 232 of file queue.cpp.

◆ reschedule()

void Queue::reschedule ( )
overridevirtual

Reschedule the jobs in the queue.

This method triggers a scheduling attempt to perform jobs. It will schedule enqueued jobs to be executed by idle threads. It should only be necessary to call it if the canRun() status of a job changed spontaneously due to external reasons.

Implements ThreadWeaver::QueueInterface.

Definition at line 237 of file queue.cpp.

◆ resume()

void Queue::resume ( )
overridevirtual

Resume job queueing.

See also
suspend

Implements ThreadWeaver::QueueInterface.

Definition at line 197 of file queue.cpp.

◆ setGlobalQueueFactory()

void Queue::setGlobalQueueFactory ( Queue::GlobalQueueFactory factory)
static

Set the factory object that will create the global queue.

Once set, the global queue factory will be deleted when the global ThreadWeaver pool is deleted. The factory object needs to be set before the global ThreadWeaver pool is instantiated. Call this method before Q(Core)Application is constructed.

Definition at line 94 of file queue.cpp.

◆ setMaximumNumberOfThreads()

void Queue::setMaximumNumberOfThreads ( int  cap)
overridevirtual

Set the maximum number of threads this Weaver object may start.

Implements ThreadWeaver::QueueInterface.

Definition at line 217 of file queue.cpp.

◆ shutDown()

void Queue::shutDown ( )
overridevirtual

Shut down the queue.

Tells all threads to exit, and changes to Destructed state. It is safe to destroy the queue once this method returns.

Implements ThreadWeaver::QueueInterface.

Definition at line 84 of file queue.cpp.

◆ state()

const State * Queue::state ( ) const
overridevirtual

Return the state of the weaver object.

Implements ThreadWeaver::QueueInterface.

Definition at line 102 of file queue.cpp.

◆ stream()

QueueStream Queue::stream ( )

Create a QueueStream to enqueue jobs into this queue.

Definition at line 79 of file queue.cpp.

◆ suspend()

void Queue::suspend ( )
overridevirtual

Suspend job execution.

When suspending, all threads are allowed to finish the currently assigned job but will not receive a new assignment. When all threads are done processing the assigned job, the signal suspended will() be emitted. If you call suspend() and there are no jobs left to be done, you will immediately receive the suspended() signal.

Implements ThreadWeaver::QueueInterface.

Definition at line 192 of file queue.cpp.


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