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HelloWorld in Objectivity/Java

Hello World!!
Description:

This quintessential helloworld program shows the basics of creating a federated database and a schema, and includes basic application that accesses the database. The application creates a database, creates a container in the database, adds objects in the container, and then retrieves these objects via a name lookup.

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Java


main.java


import com.objy.db.DatabaseNotFoundException;
import com.objy.db.DatabaseOpenException;
import com.objy.db.ObjyRuntimeException;
import com.objy.db.app.Connection;
import com.objy.db.app.Session;
import com.objy.db.app.oo;
import com.objy.db.app.ooDBObj;
import com.objy.db.app.ooFDObj;


/**
 * Main driver class
 *
 * @author Brian Clark
 * @version 1.0
 */
public class Main
{
  /**
   * Objectivity/DB HelloWorld example to store a simple HelloWorld object in
   * the database, and then retrieve it.
   *
   * @param args if specified should be a relative path to the federated
   *        database bootstrap file.
   */
  public static void main(String[] args)
  {
    boolean errors = true;
    try
    {
      System.out.println("Welcome to the Objectivity HelloWorld Example");
      // default assumes running from Samples/java/helloWorld folder
      String bootfile = "../../data/helloWorld/HelloWorld.boot";

      if (args.length == 0)
      {
        System.out.println(
          "No Objectivity FD Bootfile passed as argument; using default: " +
          bootfile);
      }
      else
      {
        bootfile = args[0];
        System.out.println("Using FD Bootfile passed as argument: " + bootfile);
      }

      //Open a read/write Connection to the Objectivity Federated Database
      //and catch the standard exceptions.
      Connection connection;

      try
      {
        connection = Connection.open(bootfile, oo.openReadWrite);
      }
      catch (DatabaseNotFoundException e1)
      {
        System.out.println("Federated database not found " + bootfile +
          "- use oonewfd to create federated database.");
        return;
      }
      catch (DatabaseOpenException e2)
      {
        System.out.println("Federated database already open.");
        return;
      }

      //Create a new Objectivity Session with client side cache
      //dimensions of at most and at least 200 pages (Page size
      //defaults to 8K on NT).
      Session session;
      session = new Session(20, 20);

      String dbName = "TestDB";

      session.setOpenMode(oo.openReadWrite);
      session.begin();

      ooFDObj fd = session.getFD();
      ooDBObj db;

      //if the database already exists, then delete it
      if (fd.hasDB(dbName))
      {
        System.out.println("Database " + dbName +
          " exists; will delete and re-create");
        db = fd.lookupDB(dbName);
        db.delete();
      }

      System.out.println("Create database");

      //create a new database file within the open federation
      try
      {
        db = fd.newDB(dbName);
      }
      catch (ObjyRuntimeException e3)
      {
        System.out.println("Database " + dbName +
          " could not be created--check free disk space.");
        session.abort();
        return;
      }

      //
      // create HelloObject and set message
      //
      System.out.println("Create HelloObject and set message");
      String name = "HelloWorld";
      HelloObject hello;
      hello = new HelloObject();
      hello.setHelloMsg(name);
      //
      //  and name it in the scope of the database
      //
      db.nameObj(hello, name);
      //
      //  commit the transaction
      //
      session.commit();
      //
      //	begin a read transaction
      //
      session.begin();
      System.out.println("Looking for object with name " + name);

      //
      //	lookup the object with name "HelloWorld" in the scope of the database
      //
      HelloObject hello2;
      try
      {
        hello2 = (HelloObject)db.lookupObj(name);
        System.out.println("Found it!: " + hello2.getHelloMsg());
        //
        //	commit the transaction
        //
        session.commit();
        //
        //	everything worked so far.
        //
        errors = false;
      }
      catch (ObjyRuntimeException e4)
      {
        System.out.println("HelloObject not found: will abort");
        session.abort();
        errors = true;
      }
    }
    finally
    {
		System.out.println("");
      if (errors)
      {
        System.out.println("HelloWorld test has FAILED");
      }
      else
      {
        System.out.println("HelloWorld test has PASSED");
      }
    }
  }
}
helloWorld.java


import com.objy.db.app.ooObj;


// Class HelloObject represents the HelloWorld object
public class HelloObject extends ooObj
{
  /** String to contain the message */
  private String mHelloMsg;

  // constructor
  public HelloObject()
  {
  }

  // sets the helloMsg value to the provided value
  void setHelloMsg(String value)
  {
	markModified();
    mHelloMsg = value;
  }

  // returns the current helloMsg value
  String getHelloMsg()
  {
	fetch();
    return mHelloMsg;
  }
}
;