Hello list,
i have a page object that contains has a Array that holds pageElements.
This is a storage for elements with an iPageElement interface.
The page object has an destroy() method. When page.destroy() is called,
it will loop trough the page.pageElements Array using an iterator. Every
iPageElement broadcasts an onElementKilled message when is has been
destroyed. When a pageElement broadcast this message, the page need to
continue in deleting the next element in the page.pageElement Array.
The callback method onElementKilled in the page instance, searches for
the element that has been deleted and then removes it from the
page.pageElements Array. This is where i think a problem rises, because
if the page.pageElements array is updated during the process, the index
does not match the element to remove anymore. How can I solve this
potential risk?
Another question, the array that is passes into the iterator is a
reference to the pageElements Array. Does this mean, that if I delete an
element from this array from within the iterator, the page.pageElements
array is modified?
I hope my question is clear..
thank you in advance.
Jiri
Below a snippet:
private function getPageElementIterator() : Void
{
return new PageElementIterator(this.pageElements)
}
//initiated the deleting proces, by starting with the first element.
public function destroyPageElements() : Void
{
destroyElement(this.pageElements[0]);
}
private function destroyElement(element:iPageElement) : Void
{
curElement.addEventListener('onElementKilled' , this)
curElement.destroy();
}
private function onElementKilled(eventObj:Object) : Void
{
var killElement:iPageElement = eventObj.target;
var iter:PageElementIterator = this.getPageElementIterator();
while(iter.hasNext()){
var curElement:iPage = iPage (iter.next());
if(killElement == curElement) {
//deleted the element now clear the listener
and continue
killElement.removeEventListener('onElementKilled' , this)
/*
* POTENTIAL RISK, if a new element is added, then the index, does
not match the right element anymore
*
* get the current index from the deleted
element by checking what
* the currentIndex of the iterator is, and remove it from
this.pageElements Array
*/
this.pageElements = this.pageElements.splice((iter.getCurrentIndex()
, 0)
//get the next element in the iterator array
if(iter.hasNext()) this.destroyElement(
iPage(iter.next()) );
delete killedElement;
break;
}
}
}
if(this.pageElements.length == 0){
trace('all page elements have been removed')
}
}
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