[AS CS5.5] Bad Perfomance: sequentially using DOM to get references

Question

Hi guys,
The issue
I'm having terrible performance problems when using a complex script I wrote.
The script
I need to make some special comparisons between found text and the texts in that page.
My script is written in Flash Builder 4, using the CS_SDK (without Extension Builder)
In short, my script has a class that performs the following tasks:
1. Finds texts that meet some criteria (by using Document.findText() method) and stores the Array of texts result in an array.
2. Traverses the Array of found texts and, for each one of them:
a. Finds a reference to the page where that text is. Something like (within a for loop, with iFoundText as the indexing var):
var currentParentPage     :Page     =
     foundText[iFoundText].parentStory.textContainers[0].parentPage;
b. Finds all the page items in that page. The code goes something like this:
var myPageItems      :Object     =
     currentParentPage.allPageItems;
c. If the PageItem is a TextFrame, then make the 'special comparison', word by word.
if (currentPageItem is TextFrame)
          var allTheWords     :Words =
               currentPageItem.words
          for (var iWord:int = 0 ; iWord < allTheWords.length ; iWord++)
               //Code to perform comparison and related operations...
It seems to work OK, when allowing to perform the script for he first three occurrences (although very slow, say some 12 seconds for this).
So, what's the problem?
What happens when I run it with more load:
When I run the script for all the occurrences (I know that the number is around 100), the application halts, an stops responding. After 10 min it doesn't work anymore.
What the documentation says:
I found a document called "FEATURE DEVELOPMENT WITH SCRIPTING - Adobe CS5" (link), where it gives this recommendation:
Performance techniques
Minimize access to InDesign DOM
Querying the InDesign DOM may be the main performance bottleneck for your script. A considerable amount of time typically is spent resolving object references, because InDesign does not hand out pointers to objects but rather uses references that need to be resolved every time they are used. Here are some techniques to alleviate this problem:
z Reduce the number of calls to the scripting DOM.
z Store and reuse resolved references in variables wherever possible.
z Use everyItem() to fetch and cache data of a collection object all at once, instead of querying the properties with separate calls.
But I don't know how to not query InDesign's DOM every time...
So. I understand that calling InDesign's DOM is bad for the script's performance, but I really don't know how could I avoid querying it for getting references to parent objects, or any other item.
I have two questions
1. If I have a variable stored in my AS script, for example:
var anyTextItem:com.adobe.indesign.Text
When I call a property or a method of that variable... Am I querying InDesign's DOM? (in other words, the variables' content is passed as a reference?)
2. How do I query the DOM less times?
For example:
Problem: I constantly need to know what's the parent page of a found text, and then get the array of page items, and then, the array of words of every page item that is a textframe.
How could I query the DOM once and then play with the stored variables instead of repetitively querying the DOM?
Because, even if I have the variable stored, say "anyTextItem:Text", and I also have all the document's TextFrames stored in other variable (say "var allTextFrames:TextFrames"), I would still need to call "anyTextItem.parentTextFrame" to get a reference to the containing textFrame, and that would mean "querying InDesign's DOM".
I would appreciate if anybody understands how to solve this.
Thanks you, guys !

Answer 1

Harbs,
Thank you very much for your answer. You're very knowledgeable about InDesign DOM.
Your message gives me a better understanding of how objects are managed between a scripting environment and the DOM. I still have some questions, though...
b.
I will change the call to 'allPageItems' to 'page.textFrames.everyItem().getElements()'. It makes much more sense.
Now, quick question:
What do you use 'getElements()' for?
What's the diference between calling 'page.textFrames.everyItem().getElements()' and 'page.textFrames.everyItem()'?
c.
OK. I kinda got it. But, I have questions here too.
For me, it's been quite tricky to understand indexes and references for InDesign DOM objects.
Let's say that I have stored a Story's words object in my script. Something like:
var currentWords     :Words = currentStory.words;
And then, I go through a TextFrame that contains part of that Story, and find one word that meets my criteria. So I get:
var foundWord        :Word = (... Somehow I got a reference to this ...);
Is it there a way to easily find that word (by index) in the 'currentWords' object? (maybe using index or id...) The problem is that I've found that sometimes the indexes don't match (i. e. if I call "foundWord.index", its index can be way larger than the parentStory.words.length, for example, I got foundWord.index=942, whereas foundWord.parentStory.length=742).
And, as a consequence, I'm using long workarounds to find the word within that collection (and I guess you'd scold me for this one; now I think that might be a serious performance killer, because I'm reconstructing the 'words' collection over and over again :S)
Thanks again to both of you (@Harbs and @Andrés), you've been very kind and helpful.