[seek-dev] get operation in ecogrid query

Bing Zhu bzhu at sdsc.edu
Tue Dec 2 16:28:06 PST 2003


I have some comments here.

1. In SRB, the identifier will be the SRB ID.
    In the get operation for SRB, this SRB ID is translated into following:
            host name  (e.g. multivac.sdsc.edu)
            Physical file name with path in that machine.
    In this case, the source will be either NULL or a port number in getting
a SRB file.

2. It is better for the return value from 'get' operation to:
        0 --> succeeded.
        a negative number -> failed. The number is the error code
corresponding to an error.
                                       In SRB, failure to retrieve a file
has many causes. 0 and 1 is not
                                       not sufficient to handle error code
3.  We need to have a way to let system admin to turn on or off the Debug
     by modifying some configuration file(s) such as server-config.wsdd
before starting SEEK Ecogrid
     factory services. I wonder how Tomcat is handling this. If they already
have a build-in function to
     check if Debug is on or off, we need to put such function call for each
System.out.println statement.


-----Original Message-----
From: seek-dev-admin at ecoinformatics.org
[mailto:seek-dev-admin at ecoinformatics.org]On Behalf Of Jing Tao
Sent: Tuesday, December 02, 2003 2:59 PM
To: seek-dev at ecoinformatics.org
Subject: [seek-dev] get operation in ecogrid query

Hi, everyone:

After struggling with some issues, the framework of get operation in
ecogrid query interface is almost done(I have not implmented read document
from metacat part, but that is not hard). Before I do that, I would
like to get some response.

The get method looks like:

int get(URI source, URI destination, String identifier).

This method is base on gsiftp and will return 1 if transfer successfully,
otherwise return 0. Besides server to client transfer, this method also
support third party transfer (ftp sever to another ftp server) too.

Now the query porttype is secured because running gsiftp need the user's
credential. So user should have a certification if he need to run the

Some issues:
The tansfer is base on file system. For example, you call the method like
this way:
URI source = new URI("gsiftp://pine.nceas.ucsb.edu:5678");
URI dest   = new URI("file:///tmp/file1");
get(source, dest, "tao.11.1");

Metacat would like read tao.11.1 from database and write it to a file.
Then gsiftp server will transfer this file  to local file /tmp/file1. It has
lot of I/Os. Maybe this way is good for srb (they store data as file).

In the code, System.out.println is used for debug info. I am think if we
need a debug class for whole seek java code or for ecogrid java code?

Any comments and suggestion are appreciated!


Jing Tao
National Center for Ecological
Analysis and Synthesis (NCEAS)
735 State St. Suite 204
Santa Barbara, CA 93101

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