import IE.Iona.Orbix2._CORBA;
import IE.Iona.Orbix2.CORBA.SystemException;
import java.util.Vector;

public class GarbageCollectorImp extends Thread
                                 implements _GarbageCollectorOperations
{
    private Vector garbageRefs;
    private Vector toDelete;
    private int waitTime = 5000;    // in milliseconds

    /**
     * Constructor for the Garbage Collector
     */
    public GarbageCollectorImp()
    {
        garbageRefs = new Vector(10, 5);
        toDelete = new Vector(10, 5);
        start();
    }

    /**
     * Continually checks all referenced objects to see if they are garbage.  If
     * any object is found to be garbage, it is disposed of.
     */
    public void run()
    {
        while (true)
        {
            try
            {
                // check only as often as defined in waitTime
                sleep(waitTime);
            }
            catch (InterruptedException ie)
            {
                System.out.println("Garbage Collector Interrupted:\n" + ie);
            }

            int count = 0;
            boolean check;
            while (count < garbageRefs.size())
            {
                check = true;
                try
                {
                    // check an object to see if it is garbage
                    check = ((_CollectableRef)garbageRefs.elementAt(count)).gcCheck();
                }
                catch (SystemException se)
                {
                    System.out.println("Garbage Collector: Could not check object:\n" + se);
                }

                // if an object is garbage
                if (check == false)
                {
                    try
                    {
                        // dispose of the object reference within the ORB
                        _CORBA.Orbix.dispose((_CollectableRef)garbageRefs.elementAt(count));
                        garbageRefs.removeElementAt(count);
                        System.out.println("Garbage Collector: disposed of object");
                    }
                    catch (SystemException se)
                    {
                        System.out.println("Garbage Collector: Could not dispose of object\n" + se);
                    }
                }
                else
                    count++;
            }
        }
    }

    /**
     * Registers an object to be checked by the collector.
     *
     * @param aRef@
     * @return true if aRef was added successfully, otherwise false@
     */
    public boolean register(_CollectableRef aRef)
    {
        garbageRefs.addElement(aRef);
        return true;
    }
}