GUIbridge Class Reference

Class for providing a bridge between the GUI thread and other threads. More...

List of all members.

Public Member Functions
def	__init__
	This is the constructor of the GUIbridge class.
def	shutdown
	This method is used to shut the GUI bridge down.
def	isGUIthread
	Returns True if this method is being called from the GUI thread.
def	createGUI
	Method used for instantiating a GUI from a non-GUI thread.
def	execGUImethodNR
	Method used for executing a GUI function from a non-GUI thread.
def	execGUImethod
	Method used for executing a GUI function from a non-GUI thread.
def	execGUImethod2
def	handleCustomEvent
Static Public Attributes
tuple	GUI_CMD_INST = QEvent.Type(QEvent.User + 1)
tuple	GUI_CMD_FUNC = QEvent.Type(QEvent.User + 2)
tuple	GUI_CMD_FUNC_NR = QEvent.Type(QEvent.User + 3)
Private Attributes
	__respQueue

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Detailed Description

Class for providing a bridge between the GUI thread and other threads.

This bridge is needed whenever a non-GUI thread needs to interact with the GUI. The GUI is handled by the 'GUI thread'. A 'GUI thread' is defined to be the one in which the Qt QApplication class's exec_loop() method is executed. There can be only one GUI thread in a program.

The solution to the problem is handled by sending a message (an 'event', in Qt terms) from the non-GUI thread to the GUI thread. The message contains information on how it is to be handled. In some cases, this handling produces a result that must be sent back to the initiating non-GUI thread. The requests and responses are passed around via queues. Separate queues are maintained for the different non-GUI threads so that responses don't end up handed off to the wrong thread.

Definition at line 28 of file guiBridges.py.

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Member Function Documentation

def __init__ (    self,   guiThread )

This is the constructor of the GUIbridge class. It must be called from the GUI thread. Definition at line 34 of file guiBridges.py.

def createGUI (    self,   qObject,   obj,   args,   kwargs )

Method used for instantiating a GUI from a non-GUI thread. Parameters: qObject  - The Qt object that will receive the customEvent callback obj  - The GUI object class type to create args  - Arguments for the object class constructor kwargs  - Keyword arguments for the object class constructor Returns: An instance of the requested GUI object class Definition at line 56 of file guiBridges.py.

def execGUImethod (    self,   qObject,   func,   args,   kwargs )

Method used for executing a GUI function from a non-GUI thread. Use this method when a response is expected from the function and when it is appropriate to wait for it (no deadlock arises) Parameters: qObject  - The Qt object that will receive the customEvent callback func  - The GUI function or method to call args  - Arguments for the function or method kwargs  - Keyword arguments for the function or method Returns: The called GUI function's return value Definition at line 95 of file guiBridges.py.

def execGUImethod2 (    self,   qObject,   func,   args,   kwargs )

Definition at line 119 of file guiBridges.py.

def execGUImethodNR (    self,   qObject,   func,   args,   kwargs )

Method used for executing a GUI function from a non-GUI thread. Use this method when no (useful) response is expected or when waiting for one could cause a deadlock. Any response from the function is lost. Parameters: qObject  - The Qt object that will receive the customEvent callback func  - The GUI function or method to call args  - Arguments for the function or method kwargs  - Keyword arguments for the function or method Definition at line 77 of file guiBridges.py.

def handleCustomEvent (    self,   e )

Definition at line 135 of file guiBridges.py.

def isGUIthread (    self  )

Returns True if this method is being called from the GUI thread. Definition at line 51 of file guiBridges.py.

def shutdown (    self  )

This method is used to shut the GUI bridge down. Definition at line 46 of file guiBridges.py.

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Member Data Documentation

__respQueue [private]

Definition at line 126 of file guiBridges.py.

tuple GUI_CMD_FUNC = QEvent.Type(QEvent.User + 2) [static]

Definition at line 31 of file guiBridges.py.

tuple GUI_CMD_FUNC_NR = QEvent.Type(QEvent.User + 3) [static]

Definition at line 32 of file guiBridges.py.

tuple GUI_CMD_INST = QEvent.Type(QEvent.User + 1) [static]

Definition at line 30 of file guiBridges.py.

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

• guiBridges.py

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