[TM4J-users] Re: resend: Problems parsing tolog queries

[kal <ka...@te...>]

Hi Bret,

If you want to query by topic id, use @id instead of the bare id in your 
query (e.g. @activity).

However, your assumption about source locators is not correct. The 
source locator for a topic is set by calling 
topic.addSourceLocator(loc), not topic.setSubject(loc). And when the 
processor resolves a string like 'activity' as a source locator it 
actually resolves it relative to the baseAddress of the topic map so you 
would need to do both of these steps:

Locator baseLoc = tm.getLocatorFactory().createLocator("URI", 
"file:///sass.xtm");
tm.setBaseLocator(baseLoc);
topic.addSourceLocator(tm.getBaseLocator().resolveRelative("#activity"));

The first two lines you only need to do once of course, and then only if 
you are not reading the topic map in from a file (if you read it in from 
a file the base address then it should get a baseLocator set automatically).

The third line you should do once and only for topics that you create 
(the ones parsed from the topic map will have a source locator set 
automatically).

Hope this helps!

Cheers,

Kal
Bret Cohen wrote:

>This is a resend. The last time I sent this, there
>were problems that prevented it from going through
>
>Kal,
>
>Once more, a problem, that once more looks like a bug,
>but almost surely isn't - yet may be a stimulant to
>improve the documentation. I've attached a file
>describing my dealings with the problem.
>
>It has to do with creating a prepared query when the
>TopicMap has *not* been read in from an XTM file. I
>have no problem when creating & executing prepared
>queries on TopicMaps read in from an XTM file.
>
>Bret
>
>
>
>
>		
>_______________________________
>Do you Yahoo!?
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>------------------------------------------------------------------------
>
>Tolog Query & Source Indicators
>
>It appears that Tolog Queries rely on source locators
>(rather than, say Topic IDs)
>for finding typing topics used within the query.
>
>This has caused me some problems, and I still haven't
>figured out the solution. (I thought I did, but
>it doesn't work.)
>
>Two possible remedies:
>1. Can I or you change the parser so that it can
>   use Topic IDs instead of source locators to locate the typing topic?
>2. Can you add documentation on creating Tolog prepared queries
>   that deals with the source locator problem?
>
>Here's my story - together with the still unresolved problem:
>
>I had never worked with source locators, until I came upon this
>Exception when I tried to create a prepared query:
>
>[java] Exception processing all activities query: org.tm4j.tologx.TologParserException: No topic in topic map with source locator SAAS.xtm#activity
>
>I never had this problem when I was working from a loaded
>XTM file, rather than from a TopicMap created from scratch
>from memory.
>
>I then realized that the the readTopicMap() method I had been using
>must have added source locators created by appending #topicID
>to the name of the XTM file from which the data was loaded -
>and that that was why queries run after reading a topic map
>from an XTM file were parsing correctly.
>
>So I figured I could create the same effect for a TopicMap
>created from scratch within memory.
> 
>So I used the name of the XTM file to which I want to later
>write the TopicMap as my "dummy base locator" for the TopicMap
>& then appended #topicID to create my source locators,
>mimicing the behavior which the readTopicMap() method
>was following.
>
>Here's an example:
>I created a typing topic for a tolog query with ID: "activity"
>I added a src locator as follows (exception processing left out)
>(Actually, I did this using a createTopic() method,
> but the result should be the same):
>Topic topic = topicMap.getTopicByID("activity");
>String baseAddress = tm.getBaseLocator().getAddress()+"#"+topic.getID();
>srcLoc = tm.getLocatorFactory().createLocator("URI", baseAddress);
>topic.setSubject(srcLoc);
>
>I then printed the source locator for the activity topic
>and the String address obtained from the locato as follows:
>
>Topic activity = tm.getTopicByID("activity");
>Locator srcLoc = activity.getSubject();
>System.out.println("srcLoc of activity topic: "+srcLoc);
>
>String srcAddr = srcLoc.getAddress();
>System.out.println("srcAddr of activity topic: "+srcAddr);
>
>The results indicated that everything went as I had planned...
>except for the parsing of the Tolog query, which continued
>to give the same error:
>    
>[java] srcLoc of activity topic: org.tm4j.net.memory.URILocatorImpl@dc5bebe1
>[java] srcAddr of activity topic: SAAS.xtm#activity
>[java] Exception processing all activities query: org.tm4j.tologx.TologParserException: No topic in topic map with source locator SAAS.xtm#activity
>
>Since I thought I had just proven that there now exists just that topic,
>I don't know why the Tolog parser is still complaining.
>(Isn't a source locator just what you get when you use
>	 topic.getSubject().getAddress?)
>  
>