Implementing IBM I job management with IBM Java Toolbox for I (ii)

IBM Java Toolbox for I programming support for IBM I subsystem

In addition to queues, subsystems are also a major feature of IBM I. IBM I supports multiple types of jobs to meet the needs of the user. Different kinds of job requirements for system resources are different, for example, interactive jobs require faster response time, batch jobs may require more CPU time, and so on. In order to use system resources more rationally and efficiently, the system is divided into several subsystems (subsystem), and all jobs are run under the control of subsystem. Therefore, the subsystem is considered to be a specially configured environment for running a certain type of job.

From the Object-oriented programming model perspective, IBM Java Toolbox for I uses the Subsystem class (located in the Com.ibm.as400.access package) to describe the IBM I subsystem object.

As an example, listing 4 describes the properties and functions of subsystem qhttpsvr, which serve HTTP server jobs.

Listing 4. QHTTPSVR Subsystem

Constructs the AS400 object to establish a connection between the Java application and the IBM I server.

AS400 sys = new AS400 (System, USR, pwd);

SUBSYSTEM SBS = new subsystem (SYS, "qhttpsvr", "qhttpsvr");

if (!sbs.exists ()) {

System.out.println ("No such subsystem:" +sbs.getpath ());

}

else {

Sbs.refresh ();

System.out.println ("Status:" + sbs.getstatus ());

System.out.println ("Number of jobs:" + sbs.getcurrentactivejobs ());

System.out.println ("Maximum jobs:" + sbs.getmaximumactivejobs ());

Wait 1 hours to stop subsystem

Sbs.end (3600);

}

As a good programming habit, release the connection

Sys.disconnectallservices ();

As with jobs, the subsystem itself is not an IBM I object, but the subsystem description (subsystem Description) is an object (*SBSD). The subsystem description defines the memory resources in the subsystem, the types of jobs that are run in the subsystem, and the maximum number of jobs. Unlike jobs, each subsystem description corresponds to only one subsystem, so the subsystem can be used to describe the object's name to differentiate between the subsystems.

From an object-oriented programming model perspective, although IBM Java Toolbox for I did not provide a dedicated subsystemdescription class to describe the IBM I subsystem descriptor object, but instead of creating a subsystem using the Subsystem class, Automatically creates a description object for the IBM I subsystem with the same name inside the code.

As an example, listing 5 describes the creation of subsystem Mysubsys, while IBM I generates an identically named and child system description object.

Listing 5. Creating subsystems and Subsystem description objects

Constructs the AS400 object to establish a connection between the Java application and the IBM I server.

AS400 sys = new AS400 (System, USR, pwd);

When a subsystem object is created, the subsystem description object of the same name is also created.

SUBSYSTEM SBS = new subsystem (SYS, "QSYS", "Mysubsys");

if (sbs.exists ()) {

SYSTEM.OUT.PRINTLN ("Subsystem Description:" +sbs.getpath () + "exists");

}

else {

Sbs.create ();

SYSTEM.OUT.PRINTLN ("Subsystem Description:" + Sbs.getpath ());

System.out.println ("Number of jobs:" + sbs.getcurrentactivejobs ());

System.out.println ("Maximum jobs:" + sbs.getmaximumactivejobs ());

}

As a good programming habit, release the connection

Sys.disconnectallservices ();