Metacat

Fixed bugs associated with the new UPDATE and DELETE functions of
DBWriter. There were problematic interactions between some static
variables used in DBEntityResolver and the way in which the
Servlet objects are re-used across multiple client invocations....

Merged in substantial changes to DBWriter and associated classes and to
the MetaCatServlet in order to accomodate the new UPDATE and DELETE
functions. The command line tools and the parameters for the
servlet have changed substantially.

Fixed bug in DBWriter using the new SAX2 interface. Turned out it was a bug in xerces-1_1_1, which was fixed by Andy Clark after I reported it.

1) Simplified database connection creation by adding new utility routine in MetaCatUtil that reads configuration information from the properties file.
2) Created MetaCatUtil.getOption() to retrieve options from properties file.
3) Unified SAX Parser creation by specifying parser driver in the properties file and dynamically loading it using the XMLReaderFactory interface....

cleaned up code for getting options from the properties file, made the database connection inthe MetaCatUtil class use the properties file for the conneciton info

updated javadoc documentation

integrated new structured query facility (DBQuery) into the servlet demo (MetaCatServlet)

removed debugging code

fixed QuerySpecification to produce SQL that does UNION or INTERSECT set operations for query group combinations

finsihed basic functionality for structured queries based on the DBQuery and QuerySpecification classes