Hi Sheryl,

> 
> Under the Comparator package in the OODT CAS Crawler Framework, there is one 
> class FilemgrUniqunessCheckComparator( with method performCheck) and though 
> this has to be satisfied before metadata extraction and ingestion, I don't 
> see any class dependent on this class or calling the method performCheck.

I'm assuming yo mean this class:

http://svn.apache.org/repos/asf/oodt/trunk/crawler/src/main/java/org/apache/oodt/cas/crawl/comparator/FilemgrUniquenessCheckComparator.java

> 
> However, under the package there is another class FilemgrUniquenessChecker 
> whose method performAction is called in CrawlerAction.  

I'm assuming you mean this class:

> http://svn.apache.org/repos/asf/oodt/trunk/crawler/src/main/java/org/apache/oodt/cas/crawl/action/FilemgrUniquenessChecker.java

> Have I missed out any class where the FilemgrUniqunessCheckComparator is 
> dependent on? 

Nope there is just a small subtlety here:

1. Crawler PreconditionComparators are used to either allow, or prevent 
metadata to be generated
2. Crawler Actions attach behavior to the preIngestion phase, the 
postIngestionSuccess phase, or the postingestionFailure phase of the crawler's 
state model *after* metadata has been generated.

So in the case of your first example, it's a Filemgr Check that *prevents 
metadata from being generated * (and thus ingestion), if the product has 
already been cataloged in an FM. In the case of your second example, it's a 
Filemgr Check *after metadata has been generated* *but before ingestion* to 
attach to the crawler phase model to prevent ingestion if you have already 
ingested that product into the FM.

In both cases the classes are called via Spring, when the crawler is running 
via attaching actions and or comparators to the crawler state model or its pre 
condition identifiers.

HTH,
Chris

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Chris Mattmann, Ph.D.
Senior Computer Scientist
NASA Jet Propulsion Laboratory Pasadena, CA 91109 USA
Office: 171-266B, Mailstop: 171-246
Email: [email protected]
WWW:   http://sunset.usc.edu/~mattmann/
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Adjunct Assistant Professor, Computer Science Department
University of Southern California, Los Angeles, CA 90089 USA
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

Reply via email to