Re: Controlling Library List -- JAVA400-L


There is nothing I could add to that description, except that in v5r1, I
"fixed" the native JDBC driver so that the
libraries property can have multiple libraries and they will get appended
to the library list.  This only applies
to naming=system as there is no concept of a library list in SQL terms.

The net:
DriverManger.getConnection("jdbc:db2:*local;naming=system;libraries=lib1
lib2 lib3");

will provide a connection with lib1, lib2 and lib3 in the library list.
You should be able to seperate the
entries in the library list with spaces, commas or colons.

Regards,

Richard D. Dettinger
AS/400 Java Data Access Team

"Biologists have a special word for stability -- dead"

                Larry Wall
                Open Source Developers Journal
                Issue 1, Jan  2000


"Shawn Church" <shawn@boxity.com>@midrange.com on 04/25/2001 12:11:46 PM

Please respond to JAVA400-L@midrange.com

Sent by:  owner-java400-l@midrange.com


To:   <JAVA400-L@midrange.com>
cc:
Subject:  Re: Controlling Library List



Here's an example I posted several weeks ago, but it was related to JDBC,
so
it may not help as far as your native program calls are concerned.

The code is not optimal, (ie - you will probably not want to instantiate
new
String objects within the resultset loop), but hopefully is clear enough.

Also, in a servlet environment you will most likely want to use a database
connection pooling mechanism rather than creating and destroying
connections
with each HTTP request.  If you are using WebSphere, it has a built-in
connection pool you can use (I have had mixed results with this), or you
can
write your own, or you can use a 3rd party package if you like.  Connection
pooling will allow you to pre-create a few connections, request a
connection
from the pool whenever you need one, use it, and return it to the pool with
out destroying the connection.  The connection pooling mechanism should be
responsible for managing the connections themselves.

You should set your date format to match the format you are using in your
table, such as ISO.  If your database and your application server (ie -
WebSphere) are on the same box, then this should be less important, but if
your application server is on a different machine than your database, it is
a good idea to set it explicitely (see the as4Properties settings below).
Trying to update a date or timestamp into a table with a mismatched date
format will give you fits.

Finally, to set a library, you have several options:

1.      For OS/400 V4R4 or later, you can opt to use the library list from
the user profile's job description (this is strict; adding a library to
your
interactive job's lib list will Not affect a java program which you invoke
interactively, but rather the lib list from your job description will be
used).  Note that for lib list searching to work, you must specify
"naming",
"system" (see below).  Prior to V4R4, QGPL will always be used.

2.      In your connection properties (see below), you can use "libraries",
"somelib" (specify a library name), to set the default library.  The name
"libraries" is misleading, since only a single library may be specified.

3.      Specify an explicit collection (library) name as part of your SQL
statement.  I prefer this method, but of course your application may be
better served using one of the other methods.  This will be something like
"select fieldname from library.table", as you will see below.  Again, if
"naming" is "system", you should use a "/" instead of a "."

Here's an example:

***

Connection as4Conn = null;
String select = null;

// Here are a few common properties which may be used in establishing your
//  database connection, but you may want to check out the other options
//  available, especially the transaction isolation (ie - journaling).

Properties as4Properties = new Properties();
as4Properties.put ("user", "someuser");
as4Properties.put ("password", "somepass");
as4Properties.put( "date format", "iso");

// Here, "naming" may be either "sql" or "system", and it determines the
separator
//      character which will be used between the collection (library) name
and the
//      table name.  I prefer the more universal "sql", but it is a
personal
preference.
//      However, if you want the library list from the job description to
be
used
//      to resolve your table name, you must use "system".

as4Properties.put( "naming", "sql");

// This will work for option #2 above:
//      as4Properties.put( "naming", "system");
//      as4Properties.put( "libraries", "whateverlib");

// URL to database.  my400db must exist in the AS/400
//      relational database (WRKRDBDIRE).
// Issue the command WRKRDBDIRE, and add a new *LOCAL
//      relational database entry called whatever you like, such as my400db
//      (You may want the name to reflect the name of your AS/400 system).

// This is the url in the form jdbc:subprotocol:subname.  The subprotocol
//      is driver dependent, and the subname is usually the name of the
//      database, including a path if appropriate (ie - non-local), such
as:
//              jdbc:db2://123.123.123.1/my400db or
//              jdbc:db2://as400name/my400db

String urlas4 = "jdbc:db2:my400db";

try {
      // Register a jdbc driver.
      // This is the native driver.  If this code is ported to
      //  a non-local host, then the toolkit driver should be used:
      //     Class is:  com.ibm.as400.access.AS400JDBCDriver",
      //     URL subcomponent is:  jdbc:as400 (instead of jdbc:db2)

      Class.forName("com.ibm.db2.jdbc.app.DB2Driver");

      // Connect to AS/400
        //  The DriverManager attempts to select an appropriate driver from
the
        //      set of registered JDBC drivers.

      as4Conn = DriverManager.getConnection(urlas4, as4Properties);

      ResultSet rs;
        try {
                Statement stmt = as4Conn.createStatement();

                select = "select field1,field2,field3 from
yourlib.yourfile"
+
                           " where yourfield='XYZ'";

                rs = stmt.executeQuery( select );
                while( rs.next()) {
                        String strField1 = rs.getString(1).trim();
                        String strField2 = rs.getString(2).trim();
                        String strField3 = rs.getString(3).trim();

                        // Do whatever you like with the data
                }
        }
        catch (Exception e) {
                e.printStackTrace();
        }
}
catch (Exception e) {
        e.printStackTrace();
}
finally {
        try {
                as4Conn.close();
        } catch (Exception e) { }
}

***

Shawn

----- Original Message -----
From: "Mark Phippard" <MarkP@softlanding.com>
To: <JAVA400-L@midrange.com>
Sent: Wednesday, April 25, 2001 11:01 AM
Subject: Controlling Library List


>
> Is there an easy and consistent way to control the library list that is
in
> effect when a Java program executes?
>
> I have a Java class that I am creating that will be making calls to
various
> "native" programs, as well as possible accessing files.  This class will
be
> executed in a variety of ways, possibly from a servlet in WebSphere,
> possibly from a CL program via RUNJVA, etc.  I would like to control the
> library list externally so that I can run the same program in different
> environments, therefore I do not want the Java class itself to manipluate
> the library list.
>
> How can this be done?  I have seen references to setting some Java
> properties, but I am not sure if that is specific to WebSphere or could
> always be used.
>
> I would be more than happy if I could just be pointed to the relevant
> documentation if it exists.
>
> Thanks
>
>
> +---
> | This is the JAVA/400 Mailing List!
> | To submit a new message, send your mail to JAVA400-L@midrange.com.
> | To subscribe to this list send email to JAVA400-L-SUB@midrange.com.
> | To unsubscribe from this list send email to
JAVA400-L-UNSUB@midrange.com.
> | Questions should be directed to the list owner: joe@zappie.net
> +---
>

+---
| This is the JAVA/400 Mailing List!
| To submit a new message, send your mail to JAVA400-L@midrange.com.
| To subscribe to this list send email to JAVA400-L-SUB@midrange.com.
| To unsubscribe from this list send email to JAVA400-L-UNSUB@midrange.com.
| Questions should be directed to the list owner: joe@zappie.net
+---



+---
| This is the JAVA/400 Mailing List!
| To submit a new message, send your mail to JAVA400-L@midrange.com.
| To subscribe to this list send email to JAVA400-L-SUB@midrange.com.
| To unsubscribe from this list send email to JAVA400-L-UNSUB@midrange.com.
| Questions should be directed to the list owner: joe@zappie.net
+---