int[] array = (int[]) ev.get_data();            result = array[RESULT];        }        catch (Exception e) {            result = -1;        }        return result;    }    /**     * Gets a Gridlet belong to the first event <b>CURRENTLY</b> waiting in this     * entity's deferred queue (incoming buffer).     * If there are no events, then wait indefinitely for an event to arrive.     * @return A Gridlet object or <tt>null</tt> if an error occurs.     * @deprecated As of GridSim 2.1, replaced by {@link #gridletReceive()}     * @pre $none     * @post $none     */    protected Gridlet GridletReceive() {        return gridletReceive();    }    /**     * Gets a Gridlet belong to the first event <b>CURRENTLY</b> waiting in this     * entity's deferred queue (incoming buffer).     * If there are no events, then wait indefinitely for an event to arrive.     * @return A Gridlet object or <tt>null</tt> if an error occurs.     * @pre $none     * @post $none     */    protected Gridlet gridletReceive()    {        Sim_event ev = new Sim_event();        // waiting for a response from the GridResource entity        Sim_type_p tag = new Sim_type_p(GridSimTags.GRIDLET_RETURN);        super.sim_get_next(tag, ev);   // wait for the correct event type        Gridlet gl = null;        try {            gl = (Gridlet) ev.get_data();        }        catch (ClassCastException c) {            gl = null;        }        catch (Exception e) {            gl = null;        }        return gl;    }    /**     * Gets a Gridlet belong to the first event <b>CURRENTLY</b> waiting in this     * entity's deferred queue (incoming buffer).     * If there are no events, then wait indefinitely for an event to arrive.     * @param gridletId   a Gridlet ID     * @param userId      a user ID     * @param resId       a grid resource ID     * @return A Gridlet object or <tt>null</tt> if an error occurs.     * @pre gridletId >= 0     * @pre userId > 0     * @pre resId > 0     * @post $none     */    protected Gridlet gridletReceive(int gridletId, int userId, int resId)    {        String errorMsg = super.get_name() + ".gridletReceive(): ";        boolean valid = validateValue(errorMsg, gridletId, userId, resId);        if (valid == false) {            return null;        }        // waiting for a response from the GridResource entity        FilterGridlet tag = new FilterGridlet(gridletId, userId, resId);        // only look for this type of ack for same Gridlet ID        Sim_event ev = new Sim_event();        super.sim_get_next(tag, ev);        Gridlet gl = null;        try {            gl = (Gridlet) ev.get_data();        }        catch (ClassCastException c) {            gl = null;        }        catch (Exception e) {            gl = null;        }        return gl;    }    /**     * Gets a Gridlet belong to the first event <b>CURRENTLY</b> waiting in this     * entity's deferred queue (incoming buffer).     * If there are no events, then wait indefinitely for an event to arrive.     * @param gridletId   a Gridlet ID     * @param resId       a grid resource ID     * @return A Gridlet object or <tt>null</tt> if an error occurs.     * @pre gridletId >= 0     * @pre resId > 0     * @post $none     */    protected Gridlet gridletReceive(int gridletId, int resId)    {        String errorMsg = super.get_name() + ".gridletReceive(): ";        boolean valid = validateValue(errorMsg,gridletId,super.get_id(),resId);        if (valid == false) {            return null;        }        // waiting for a response from the GridResource entity        FilterGridlet tag = new FilterGridlet(gridletId, resId);        // only look for this type of ack for same Gridlet ID        Sim_event ev = new Sim_event();        super.sim_get_next(tag, ev);        Gridlet gl = null;        try {            gl = (Gridlet) ev.get_data();        }        catch (ClassCastException c) {            gl = null;        }        catch (Exception e) {            gl = null;        }        return gl;    }    /**     * Sends a Gridlet based on their event tag to the destination resource ID.     * @param errorMsg   a message containing which operation it belongs to     * @param gridletId  a Gridlet ID     * @param userId     a Gridlet's user or owner ID     * @param resourceId    a GridResource ID     * @param delay      sending delay time     * @param tag        event tag (such as GridSimTags.GRIDLET_PAUSE, etc...)     * @param ack        denotes whether want to have an acknowledgment or not     * @return <tt>true</tt> if the Gridlet has been sent successfully,     *         <tt>false</tt> otherwise     * @pre errorMsg != null     * @pre gridletId > 0     * @pre userId > 0     * @pre resourceId > 0     * @pre delay >= 0.0     * @pre tag > 0     * @post $result = true || false     */    private boolean sendGridlet(String errorMsg, int gridletId, int userId,                           int resourceId, double delay, int tag, boolean ack)    {        boolean valid = validateValue(errorMsg, gridletId, userId, resourceId);        if (valid == false || delay < 0.0) {            return false;        }        int size = 14;  // size of having 3 ints + 2 bytes overhead        int[] array = new int[ARRAY_SIZE];        array[0] = gridletId;        array[1] = userId;        array[2] = NOT_FOUND;  // this index is only used by gridletMove()        // if an ack is required, then change the tag        int newTag = tag;        if (ack == true)        {            switch (tag)            {                case GridSimTags.GRIDLET_PAUSE:                    newTag = GridSimTags.GRIDLET_PAUSE_ACK;                    break;                case GridSimTags.GRIDLET_RESUME:                    newTag = GridSimTags.GRIDLET_RESUME_ACK;                    break;                default:                    break;            }        }        // send this Gridlet        send(super.output, delay, newTag, new IO_data(array, size, resourceId));        return true;    }    /**     * Performs validation of the given parameters before sending a Gridlet     * to a GridResource entity     * @param msg        a message containing which operation it belongs to     * @param gridletId  a Gridlet ID     * @param userId     a Gridlet's user or owner ID     * @param resourceId    a GridResource ID     * @return <tt>true</tt> if the validation has passed successfully,     *         <tt>false</tt> otherwise     * @pre msg != null     * @pre gridletId > 0     * @pre userId > 0     * @pre resourceId > 0     * @post $result = true || false     */    private boolean validateValue(String msg, int gridletId, int userId,                int resourceId)    {        boolean valid = true;        // Gridlet ID must be 0 or positive        if (gridletId < 0)        {            valid = false;            System.out.println(msg + "Error - Gridlet ID must be >= 0, not " +                    gridletId);        }        // User ID must be 0 or positive        if (userId < 0)        {            valid = false;            System.out.println(msg + "Error - User ID must be >= 0, not " +                    userId);        }        // GridResource ID must be 0 or positive        if (resourceId < 0)        {            valid = false;            System.out.println(msg +                    "Error - GridResource ID must be >= 0, not " + resourceId);        }        // if a grid resource ID doesn't exist in GIS list        if (gis_.isResourceExist(resourceId) == false)        {            valid = false;            System.out.println(msg + "Error - GridResource ID #" + resourceId +                               " doesn't exist");        }        return valid;    }    /**     * Cancels a Gridlet that is currently executing in a given GridResource     * ID <tt>with</tt> a delay. <br>     * <b>NOTE:</b> Canceling a Gridlet operation can take a long time over a     *              slow network if the Gridlet size is big.     * @param gl            a Gridlet object to be canceled     * @param resourceId    an unique resource ID     * @param delay         delay time or <tt>0.0</tt> if want to cancel NOW     * @return the canceled Gridlet or <tt>null</tt if this operation fails.     *         If a Gridlet has <tt>finished</tt> in time of cancellation, then     *         this method will return the finished Gridlet.     *         Canceling a Gridlet can be failed for the one or more     *         following reasons:     *         <ul>     *              <li> if a GridResource ID doesn't exist     *              <li> if a Gridlet ID doesn't exist     *              <li> if a Gridlet's user ID doesn't exist     *              <li> if the delay time is negative     *              <li> if a Gridlet object is <tt>null</tt> or empty;     *         </ul>     * @pre gl != null     * @pre resourceId >= 0     * @pre delay >= 0.0     * @post $none     */    protected Gridlet gridletCancel(Gridlet gl, int resourceId, double delay)    {        if (gl == null || delay < 0.0) {            return null;        }        Gridlet obj = gridletCancel( gl.getGridletID(), gl.getUserID(),                                    resourceId, delay );        return obj;    }    /**     * Cancels a Gridlet that is currently executing in a given GridResource     * ID <tt>with</tt> a delay. <br>     * <b>NOTE:</b> Canceling a Gridlet operation can be slow over a slow     *              network if the Gridlet size is big.     * @param gridletId     a Gridlet ID     * @param userId        the user or owner ID of this Gridlet     * @param resourceId    an unique resource ID to which this Gridlet was     *                      previously sent to     * @param delay         delay time or <tt>0.0</tt> if want to cancel NOW     * @return the canceled Gridlet or <tt>null</tt if this operation fails.     *         If a Gridlet has <tt>finished</tt> in time of cancellation, then     *         this method will return the finished Gridlet.     *         Canceling a Gridlet can be failed for the one or more     *         following reasons:     *         <ul>     *              <li> if a GridResource ID doesn't exist     *              <li> if a Gridlet ID doesn't exist     *              <li> if a Gridlet's user ID doesn't exist     *              <li> if the delay time is negative     *         </ul>     * @pre gridletId >= 0     * @pre userId >= 0     * @pre resourceId >= 0     * @pre delay >= 0.0     * @post $none     */    protected Gridlet gridletCancel(int gridletId, int userId, int resourceId,                                    double delay)    {        Gridlet gl = null;        String errorMsg = super.get_name() + ".gridletCancel(): ";        try        {            boolean valid = sendGridlet(errorMsg, gridletId, userId, resourceId,                                    delay, GridSimTags.GRIDLET_CANCEL, false);            if (valid == true)            {                // waiting for a response from the GridResource entity                FilterGridlet tag = new FilterGridlet(gridletId, resourceId);                tag.setTag(GridSimTags.GRIDLET_CANCEL);                // only look for this type of ack for same Gridlet ID                Sim_event ev = new Sim_event();                super.sim_get_next(tag, ev);                gl = (Gridlet) ev.get_data();                // if a gridlet comes with a failed status, it means that                // a resource could not find the gridlet                if (gl.getGridletStatus() == Gridlet.FAILED) {                    gl = null;                }            }        }        catch (Sim_exception e)        {            gl = null;            System.out.println(errorMsg + "Error occurs.");