topic Re: Java on VMS - Retrieving logical names and equivalence names programmatically in Operating System - OpenVMS

Java on VMS - Retrieving logical names and equivalence names programmatically

Llewellyn Robinson — Fri, 19 Feb 2010 05:46:13 GMT

In Java on OpenVMS, how do you retrieve VMS logical names and equivalence names?

System.getenv() returns only a few seemingly java related items.
System.getProperties() similarly only returns java related items.

Re: Java on VMS - Retrieving logical names and equivalence names programmatically

Steven Schweda — Fri, 19 Feb 2010 06:00:07 GMT

Really? My Java experience in minimal, but
the C RTL function getenv() certainly can do
more than that, and I'd expect the Java stuff
to use it. ("HELP CRTL GETENV".) Do you
have a convenient demonstration program?

Re: Java on VMS - Retrieving logical names and equivalence names programmatically

Bojan Nemec — Fri, 19 Feb 2010 07:29:30 GMT

Llewellyn,

Welcome to the OpenVMS forum.

See the release notes description of System.getenv():

http://h18012.www1.hp.com/java/documentation/1.5.0/ovms/docs/release_notes.html#usinggetenv

Bojan

Re: Java on VMS - Retrieving logical names and equivalence names programmatically

Hoff — Fri, 19 Feb 2010 13:37:01 GMT

Or depending on what (else) you're after, the JNI:

http://labs.hoffmanlabs.com/node/1271

Re: Java on VMS - Retrieving logical names and equivalence names programmatically

Llewellyn Robinson — Sun, 21 Feb 2010 23:53:18 GMT

My original goal was to be able to search through all logicals on the system that end with "$database", in order to perform some tasks on each Rdb database that the logicals pointed to.

It seems that the JVM will only be allowed access to the logicals that I specify in another logical, thus preventing the ability for my app to automatically discover the databases through these means.

Also, it turns out we're running a JVM too old to use JAVA$GETENV_SYSTEM_LIST etc. We're on 1.5.0-3.

Thanks for your help.

Re: Java on VMS - Retrieving logical names and equivalence names programmatically

Llewellyn Robinson — Mon, 22 Feb 2010 03:50:14 GMT

The System.getenv() release helps me but doesn't solve my issue completely.

Re: Java on VMS - Retrieving logical names and equivalence names programmatically

John Gillings — Mon, 22 Feb 2010 04:35:11 GMT

Llewellyn,
This has always been a hole in the OpenVMS logical name services. There's no documented interface to do wildcard searches of logical name tables. The SHOW LOGICAL command can do it, but there's no $TRNLNM mechanism (and hence, no getenv).

You could parse the output of a SHOW LOGICAL, but that gets very ugly :-(