BluezQt::Job Class

Member Function Documentation

[explicit] Job::Job(QObject *parent = nullptr)

Creates a new Job object as a child of parent.

[pure virtual protected] void Job::doEmitResult()

Implementation for emitting the result signal.

This function is needed to be able to emit result() signal with the job pointer's type being subclass.

[pure virtual protected slot] void Job::doStart()

Implementation for start() that will be executed in next loop

This slot is always called in the next loop, triggered by start().

When implementing this method is important to remember that jobs are not executed on a different thread (unless done that way), so any blocking task has to be done in a different thread or process.

[protected] void Job::emitResult()

Utility function to emit the result signal, and remove this job.

See also result().

int Job::error() const

Returns the error code for this job if there has been an error.

Make sure to call this once result() has been emitted.

See also setError().

QString Job::errorText() const

Returns the error text if there has been an error.

Only call if error is not 0.

This is usually some extra data associated with the error, such as a URL. Use errorString() to get a human-readable, translated message.

See also setErrorText().

bool Job::exec()

Executes the job synchronously.

This will start a nested QEventLoop internally. Nested event loop can be dangerous and can have unintended side effects, you should avoid calling exec() whenever you can and use the asynchronous interface of Job instead.

Should you indeed call this method, you need to make sure that all callers are reentrant, so that events delivered by the inner event loop don't cause non-reentrant functions to be called, which usually wreaks havoc.

Note that the event loop started by this method does not process user input events, which means your user interface will effectively be blocked. Other events like paint or network events are still being processed. The advantage of not processing user input events is that the chance of accidental reentrancy is greatly reduced. Still you should avoid calling this function.

Returns true if the job has been executed without error, false otherwise.

bool Job::isFinished() const

Returns whether the job has already finished.

bool Job::isRunning() const

Returns whether the job is currently running.

[slot] void Job::kill()

Kills the job.

This method will kill the job and then call deleteLater(). Only jobs started with start() can be killed.

It will not emit the result signal.

[protected] void Job::setError(int errorCode)

Sets the errorCode.

It should be called when an error is encountered in the job, just before calling emitResult().

You should define an enum of error codes, with values starting at Job::UserDefinedError, and use those. For example:

enum ExampleErrors{
  InvalidFoo = UserDefinedError,
  BarNotFound
};

See also error() and emitResult().

[protected] void Job::setErrorText(const QString &errorText)

Sets the errorText.

It should be called when an error is encountered in the job, just before calling emitResult().

Provides extra information about the error that cannot be determined directly from the error code. For example, a URL or filename. This string is not normally translatable.

See also errorText(), emitResult(), and setError().

[slot] void Job::start()

Starts the job asynchronously.

This method will schedule doStart() to be executed in the next loop. This is done so this method returns as soon as possible.

When the job is finished, result() is emitted.