Thanks you John for your valuable comments. I will refresh my experience with calling Widget.dispose() and its effect on children widgets.
26.09.2014 17:07, John Spackman пишет: > Hi Dimitri > > It sounds like you’ve probably read this page but just in case: > http://manual.qooxdoo.org/current/pages/development/memory_management.html > >> 1. Best place to dispose objects programmatically is the destructor. Is >> that right? > Yes > >> 2. Are destructors inherently virtual? I've never seen a destructor that >> calls a base class destructor. Does qooxdoo call base class destructors? > Yes, destructors all the way up the hierarchy are automatically called, > there’s no need for this.base(…) > >> 2. References to other objects stored in properties. Does qooxdoo >> nullify the properties at disposal? >> > Object._disposeObjects (which is qx.util.DisposeUtil) does set properties to > null, but the destructor does not nullify property values. > >> 3. Extra care should be taken not to dispose the same object more than >> once. Programmer should keep an eye on references. References can be >> created directly and indirectly. Direct references are member variables. >> Indirect references are managed by containers such as Composite, etc. >> Another case of indirect reference is a parent-child relationship inside >> complex widgets, I mean "createChildControlImpl”. > Yes - taking care of only disposing once is a PITA but unavoidable. As a > general rule of good design, each widget should only dispose of it’s own > objects and contained objects should be relied upon to dispose of their own > objects. > >> 3.1. Does a call to dispose automatically remove the reference from the >> parent container (e.g. Composite)? > Yes > >> 4. References to other objects stored as member variables. I think that >> this case is completely up to the programmer. He/she should explicitly >> dispose objects and then nullify the references. qx.util.DisposeUtil may >> become handy at that. Instead of disposing a group of objects one by >> one, one may call qx.util.DisposeUtil.disposeObjects(this, >> ["foo","bar","etc"]) to dispose them all at once. It's not that simple >> however. This method does not fully dispose containers such as >> Composite, etc. If you are disposing containers then there is a risk of >> losing references of their children and thus never being able to dispose >> them. > It doesn’t? AIUI calling dispose() on a Widget will dispose all of the > contained child widgets recursively > >> 4.1. If you want to dispose containers along with their children you can >> use destroyContainer from qx.util.DisposeUtil. > Maybe this bit if DisposeUtil is out of date; Widget.destruct calls > Widget._disposeChildControls() > >> 5. Indirect references to widgets created via "createChildControlImpl". >> Should I ever dispose them manually? These widgets may easily be >> Composites with their own children collections. So I definitely should >> dispose such collections (#4.1). > Not necessary > >> 6. Listeners. Does qooxdoo automatically nullify references to event >> listeners when their event source gets disposed? >> > Yes. > > Hope that helps > > John > > > > ------------------------------------------------------------------------------ > Meet PCI DSS 3.0 Compliance Requirements with EventLog Analyzer > Achieve PCI DSS 3.0 Compliant Status with Out-of-the-box PCI DSS Reports > Are you Audit-Ready for PCI DSS 3.0 Compliance? Download White paper > Comply to PCI DSS 3.0 Requirement 10 and 11.5 with EventLog Analyzer > http://pubads.g.doubleclick.net/gampad/clk?id=154622311&iu=/4140/ostg.clktrk > _______________________________________________ > qooxdoo-devel mailing list > qooxdoo-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/qooxdoo-devel > > . > ------------------------------------------------------------------------------ Meet PCI DSS 3.0 Compliance Requirements with EventLog Analyzer Achieve PCI DSS 3.0 Compliant Status with Out-of-the-box PCI DSS Reports Are you Audit-Ready for PCI DSS 3.0 Compliance? Download White paper Comply to PCI DSS 3.0 Requirement 10 and 11.5 with EventLog Analyzer http://pubads.g.doubleclick.net/gampad/clk?id=154622311&iu=/4140/ostg.clktrk _______________________________________________ qooxdoo-devel mailing list qooxdoo-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/qooxdoo-devel
