[jsword-devel] Forking conversation to discuss bug in ZVerseBackend (and potentially other backends?)

DM Smith dmsmith at crosswire.org
Tue Nov 9 13:49:20 MST 2010


On 11/07/2010 07:40 AM, Chris Burrell wrote:
> I believe the problem is because ZVerseBackend is not thread-safe. 
> Being a singleton, it starts sharing all its arrays declared as member 
> variables. As a result, when two passages from the same "Book" (for 
> e.g. KJV) are used, there is corruption, since the data read for 
> Thread A might also be shared by Thread B!
>
> A few solutions I can think of:
> - do they need to be singletons? I guess it makes sense, but what is 
> the cost involved in them being singletons? Don't know the code base 
> well enough yet.
> - do the member variables need to member variables, or can be make 
> them local variables? Do they share state across methods?
> - If the option above doesn't work, then synchronising the method 
> might be worth looking at, however, in a web environment, that would 
> potentially cause serious bottlenecks, especially if there is a 
> default version (and default passage) that is displayed when the user 
> brings the page up.

This is a design flaw. It should be fixed. I'll take it up in the Jira 
issue you opened.

The basic issue is that the backend caches data in the assumption that 
if you asked for one verse, you are likely to ask for the next. Getting 
verses out of a compressed module is expensive.

>
> Any thoughts?
> Chris
>
>
>
> On 7 November 2010 00:04, Chris Burrell <chris at burrell.me.uk 
> <mailto:chris at burrell.me.uk>> wrote:
>
>     On this last note, I believe we have concurrency issues. I have a
>     two column page, displaying one passage each. On load of the page
>     they load up a passage each, but then this once, the passage on
>     the right (only verse 1) has gone to the left (which was
>     requesting just one verse but from a different passage:
>
>     left pane: requested Acts 2:10, got Romans 1:1
>     right pane: corrupt XML in verse 1, verse 2 seems to be Romans
>     1:2-following
>
>     Anyone else come across those issues?
>     Chris
>
>     On 6 November 2010 20:53, Chris Burrell <chris at burrell.me.uk
>     <mailto:chris at burrell.me.uk>> wrote:
>
>         Another question too. It seems sometimes, both in bible
>         desktop and my current application, the html rendered is broken?
>
>         Any ideas why that might be?
>
>         For example, I get:
>         "<div class="passageText ui-widget"><div><h2
>         class="heading">Acts 2:10</h2><span class="verse"><span
>         class="w"><sup class="verseNumber">10</sup></span><span
>         class="w"*><span class="text">emma="strong:G1909"
>         morph="robinson:PREP*" src="4"&gt;upon every soul of man that
>         doeth evil, of the Jew first, and also of the
>         Gentile;</span></span></span> </div></div>"
>
>         The above in bold shows that it didn't get XSLTed properly.
>
>         Instead of "<div class="passageText ui-widget"><div><h2
>         class="heading">Acts 2:10</h2><span class="verse"><sup
>         class="verseNumber">10</sup><span class="w"><span
>         class="text">&nbsp;</span> </span><span class="w"><span
>         class="text">&nbsp;</span> </span><span class="w"><span
>         class="text">Phrygia</span></span>, <span class="w"><span
>         class="text">&nbsp;</span> </span><span class="w"><span
>         class="text">and</span></span> <span class="w"><span
>         class="text">Pamphylia</span></span>, <span class="w"><span
>         class="text">in Egypt</span></span>, <span class="w"><span
>         class="text">and</span></span> <span class="w"><span
>         class="text">in the parts</span></span> <span class="w"><span
>         class="text">of Libya</span></span> <span class="w"><span
>         class="text">about</span></span> <span class="w"><span
>         class="text">Cyrene</span></span>, <span class="w"><span
>         class="text">and</span></span> <span class="w"><span
>         class="text">strangers</span></span> <span class="w"><span
>         class="text">of Rome</span></span>, <span class="w"><span
>         class="text">Jews</span></span> <span class="w"><span
>         class="text">&nbsp;</span> </span><span class="w"><span
>         class="text">and</span></span> <span class="w"><span
>         class="text">proselytes</span></span>,</span> </div></div>"
>
>         So somehow it lost a whole load on the way out of the XSLT?
>         The only difference is that the first one is on startup of the
>         server, the second is with a refresh in the browser. Perhaps
>         something hasn't loaded up correctly/entirely?
>
>         Chris
>
>         On 5 November 2010 23:10, Chris Burrell <chris at burrell.me.uk
>         <mailto:chris at burrell.me.uk>> wrote:
>
>             Thanks DM. So I found this page (again)!
>             http://www.crosswire.org/~dmsmith/interlinear/
>             <http://www.crosswire.org/%7Edmsmith/interlinear/>
>
>             And managed to replicate (and solve?) the issues I found
>             originally when I looked at it before:
>
>             1st When lines in the interlinear only have 1 line (i.e.
>             no 2nd/3rd or 4th line). As a result, when the text wraps,
>             it floats below the first line. As a hack (although on
>             could argue that there is an empty spot there, rather than
>             nothing), I think we can put a <span>&nbsp;</span> or we
>             could use a height maybe? (not quite so good, unless we
>             specify in ems and exs). And the second thing is that
>             within a particular word stack, the words might wrap. I
>             believe this particular issue is only visible in IE. For
>             IE 8, the fix is to put a whitespace: nowrap CSS
>             directive. Not sure if that helps on IE6 and 7 though?
>             Spec says it should be supported on both browsers.
>
>             And yup, I'm targetting web environments, and also web
>             mobile browsers.
>             Chris
>
>
>             On 5 November 2010 20:09, DM Smith <dmsmith at crosswire.org
>             <mailto:dmsmith at crosswire.org>> wrote:
>
>                 I'm heading out for the weekend. In a few minutes.
>                 It'll probably be Monday evening when I send it.
>
>                 The solution uses spans with their display set to block.
>
>                 -- DM
>
>
>                 On 11/05/2010 03:55 PM, Chris Burrell wrote:
>>                 DM, you said you might have an intearlinear model
>>                 that worked? I had another look to see how I did mine
>>                 previously, and found that in fact I used tables. I
>>                 think I struggled for quite a while to get a model
>>                 working across browsers using DIVs, but none of them
>>                 seemed to wrap properly at the end of the line.  But
>>                 unfortunately table layouts are slow and therefore it
>>                 would be better to have divs.
>>
>>                 Would you be able to let me have your samples?
>>                 Chris
>>
>>                 On 5 November 2010 19:21, Chris Burrell
>>                 <chris at burrell.me.uk <mailto:chris at burrell.me.uk>> wrote:
>>
>>                     What's GNT? Greek New Testament? I think we can
>>                     do more than that too. If other Bible versions
>>                     have strong numbers and/or morphology tags, then
>>                     we can put those in parallel, and end up having
>>                     French with English "subtitles", or English with
>>                     English, as well as English with Greek, etc.
>>
>>                     So I've had a look at the framework so far and it
>>                     seems fairly easy not to use Bible Desktop
>>                     components and have a good XSLT transformation.
>>                     So all we would need to add is some helpers that
>>                     users can easily integrate into their XSLTs. It
>>                     would nice to have some sample XSLs for people to
>>                     use. So for example, I've had to strip out all
>>                     the CSS and font tags from the Bible Desktop one
>>                     so as to produce a good XHTML compliant one.
>>
>>                     Say we give the XSLT a InterlinearProvider
>>                     initialised with its version and passage, as it
>>                     parses the strong/morph option we can then call
>>                     get($provider, @strong, @morph), which would in
>>                     turn optionally return the correct words (or best
>>                     word since sometimes you may have multiple
>>                     options in modules tagged with strong numbers
>>                     only. In fact it would be better to have
>>                     something like get($provider, osis_verse_id,
>>                     @strong, @morph). Since then, if we don't have
>>                     the morphology of the word, at least we can limit
>>                     the lookups to those words that are tagged in a
>>                     particular verse (that assumes that versification
>>                     is comparable between versions).
>>
>>                     We'll want to add options to have tagged
>>                     information displayed on the side of a
>>                     word/phrase or below a word/phrase. At the moment
>>                     the XSLT displays morph and strong tags next to
>>                     the text. I'll add some transformations to have
>>                     it on separate lines. Then we can reuse the same
>>                     transformations to line up text beneath it.
>>
>>                     DM, I had a look at "flying saucer" , but didn't
>>                     quite understand where it comes in? Would the
>>                     idea be instead of the XSLT? And have it
>>                     transform to different UIs?
>>
>>                     Chris
>>
>>
>>                     On 5 November 2010 03:51, Tonny Kohar
>>                     <tonny.kohar at gmail.com
>>                     <mailto:tonny.kohar at gmail.com>> wrote:
>>
>>                         Hi,
>>
>>                         On Thu, Nov 4, 2010 at 11:30 PM, DM Smith
>>                         <dmsmith at crosswire.org
>>                         <mailto:dmsmith at crosswire.org>> wrote:
>>                         > Much of the transformations is done in
>>                         BibleDesktop. Refactoring these and
>>                         > putting it into JSword and/or common would
>>                         be good.
>>                         >
>>
>>                         +1
>>                         Yes it would be nice to have this under
>>                         JSword instead of BIbleDesktop
>>
>>                         Sincerely
>>                         Tonny Kohar
>>

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