RFR (JAXP) : 8081248: Implement JEP 268: XML Catalog API

[huizhe wang]

Hi all,

Please help review JEP 268 implementation:
https://bugs.openjdk.java.net/browse/JDK-8081248

Catalog specification:
https://www.oasis-open.org/committees/download.php/14809/xml-catalogs.html

webrevs:
http://cr.openjdk.java.net/~joehw/jdk9/8081248/webrev/


A Catalog is basically an ordered list of entries that map external 
references to local resources using string identifiers called 
systemId/publicId. The main function of the Catalog API therefore is 1) 
parse a catalog; 2) use it to find a matching entry and resolve the 
resource referenced in an XML document.

For common use cases, an application would simply acquire a 
CatalogResolver and set it on a parser to be used for resource 
resolution, refer to the test for an example.

The unit test contains test cases for the simple entries. Since SQE test 
development has been in parallel with the dev work, this unit test 
didn't have to cover all of the functions. What it does is to test and 
demonstrate the use in a real environment, using a CatalogResolver to 
actually resolves resources in XML documents, while the SQE tests focus 
on having a full coverage by matching literal strings without involving 
XML documents.  The SQE test suite has gone through internal reviews and 
will start public review following this review.

Thanks,
Joe