System.out.println( e.getMessage() );        }        catch (Exception e)        {            gl = null;            System.out.println(errorMsg + "Error occurs.");            System.out.println( e.getMessage() );        }        return gl;    }    /**     * Pauses a Gridlet that is currently executing in a given GridResource     * ID <tt>with</tt> a delay.     * @param gl            a Gridlet object to be sent     * @param resId         an unique resource ID     * @param delay         delay time or <tt>0.0</tt> if want to execute NOW     * @return <tt>true</tt> if this Gridlet has been paused successfully in the     *         destination GridResource, <tt>false</tt> otherwise.     *         Pausing 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;     *              <li> if a Gridlet object has <tt>finished</tt> executing     *                   beforehand. The Gridlet needs to be retrieved by     *                   using {@link #gridletReceive()}     *         </ul>     * @pre gl != null     * @pre resId >= 0     * @pre delay >= 0.0     * @post $none     */    protected boolean gridletPause(Gridlet gl, int resId, double delay)    {        if (gl == null || delay < 0.0) {            return false;        }        return gridletPause(gl.getGridletID(),gl.getUserID(),resId,delay,true);    }    /**     * Pauses a Gridlet that is currently executing in a given GridResource     * ID <tt>with</tt> a delay.     * @param gridletId     a Gridlet ID     * @param userId        the user or owner ID of this Gridlet     * @param resourceId    an unique resource ID     * @param delay         delay time or <tt>0.0</tt> if want to execute NOW     * @param ack   an acknowledgement, i.e. <tt>true</tt> if wanted to know     *        whether this operation is success or not, <tt>false</tt>     *        otherwise (don't care)     * @return <tt>true</tt> if this Gridlet has been paused successfully in the     *         destination GridResource, <tt>false</tt> otherwise.     *         Pausing 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 has <tt>finished</tt> executing     *                   beforehand. The Gridlet needs to be retrieved by using     *                   {@link #gridletReceive()}     *         </ul>     * @pre gridletId >= 0     * @pre userId >= 0     * @pre resourceId >= 0     * @pre delay >= 0.0     * @post $none     */    protected boolean gridletPause(int gridletId, int userId, int resourceId,                                   double delay, boolean ack)    {        boolean valid = false;        String errorMsg = super.get_name() + ".gridletPause(): ";        try        {            valid = sendGridlet(errorMsg, gridletId, userId, resourceId, delay,                                GridSimTags.GRIDLET_PAUSE, ack);            if (valid == true && ack == true)            {                valid = getBooleanResult(gridletId,                                         GridSimTags.GRIDLET_PAUSE_ACK);            }        }        catch (Sim_exception e)        {            valid = false;            System.out.println(errorMsg + "Error occurs.");            System.out.println( e.getMessage() );        }        catch (Exception e)        {            valid = false;            System.out.println(errorMsg + "Error occurs.");            System.out.println( e.getMessage() );        }        return valid;    }    /**     * Gets the current status of this Gridlet in a given GridResource ID     * @param gl    a Gridlet object     * @param resourceId   a GridResource ID that executes this Gridlet object     * @return the current Gridlet status or <tt>-1</tt> if not found.     *         The various Gridlet status can be found in Gridlet class.     * @see gridsim.Gridlet     * @pre gl != null     * @pre resourceId > 0     * @post $none     */    protected int gridletStatus(Gridlet gl, int resourceId)    {        if (gl == null) {            return NOT_FOUND;        }        return gridletStatus(gl.getGridletID(), gl.getUserID(), resourceId);    }    /**     * Gets the current status of this Gridlet in a given GridResource ID     * @param gridletId    a Gridlet ID     * @param userId       the user or owner of this Gridlet object     * @param resourceId   a GridResource ID that executes this Gridlet object     * @return the current Gridlet status or <tt>-1</tt> if not found.     *         The various Gridlet status can be found in Gridlet class.     * @see gridsim.Gridlet     * @pre gridletId > 0     * @pre userId > 0     * @pre resourceId > 0     * @post $none     */    protected int gridletStatus(int gridletId, int userId, int resourceId)    {        int status = NOT_FOUND;        String errorMsg = super.get_name() + "gridletStatus(): ";        try        {            boolean valid = sendGridlet(errorMsg, gridletId, userId, resourceId,                                        0.0, GridSimTags.GRIDLET_STATUS, false);            if (valid == false) {                return status;            }            // waiting for a response from the GridResource            status = getIntResult(gridletId, GridSimTags.GRIDLET_STATUS);        }        catch (Sim_exception e)        {            status = NOT_FOUND;            System.out.println(errorMsg + "Error occurs.");            System.out.println( e.getMessage() );        }        catch (Exception e)        {            status = NOT_FOUND;            System.out.println(errorMsg + "Error occurs.");            System.out.println( e.getMessage() );        }        return status;    }    /**     * Resumes a Gridlet that is currently pausing in a given GridResource     * ID <tt>with</tt> a delay.<br>     * <b>NOTE:</b> Resuming a Gridlet only works if it is currently on paused.     * @param gl            a Gridlet object to be sent     * @param resId         an unique resource ID     * @param delay         delay time or <tt>0.0</tt> if want to execute NOW     * @return <tt>true</tt> if this Gridlet has been resumed successfully in     *         the destination GridResource, <tt>false</tt> otherwise.     *         Resuming 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     *              <li> if a Gridlet is not currently on paused     *         </ul>     * @pre gl != null     * @pre resId >= 0     * @pre delay >= 0.0     * @post $none     */    protected boolean gridletResume(Gridlet gl, int resId, double delay)    {        if (gl == null || delay < 0.0) {            return false;        }        return gridletResume(gl.getGridletID(),gl.getUserID(),resId,delay,true);    }    /**     * Resumes a Gridlet that is currently pausing in a given GridResource     * ID <tt>with</tt> a delay. <br>     * <b>NOTE:</b> Resuming a Gridlet only works if it is currently on paused.     * @param gridletId     a Gridlet ID     * @param userId        the user or owner ID of this Gridlet     * @param resourceId    an unique resource ID     * @param delay         delay time or <tt>0.0</tt> if want to execute NOW     * @param ack   an acknowledgement, i.e. <tt>true</tt> if wanted to know     *        whether this operation is success or not, <tt>false</tt>     *        otherwise (don't care)     * @return <tt>true</tt> if this Gridlet has been resumed successfully in     *         the destination GridResource, <tt>false</tt> otherwise.     *         Resuming 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 is not currently on paused     *         </ul>     * @pre gridletId >= 0     * @pre userId >= 0     * @pre resourceId >= 0     * @pre delay >= 0.0     * @post $none     */    protected boolean gridletResume(int gridletId, int userId, int resourceId,                                    double delay, boolean ack)    {        boolean valid = false;        String errorMsg = super.get_name() + ".gridletResume(): ";        try        {            valid = sendGridlet(errorMsg, gridletId, userId, resourceId, delay,                                GridSimTags.GRIDLET_RESUME, ack);            if (valid == true && ack == true)            {                // waiting for a response from the GridResource                valid = getBooleanResult(gridletId,                                         GridSimTags.GRIDLET_RESUME_ACK);            }        }        catch (Sim_exception e)        {            valid = false;            System.out.println(errorMsg + "Error occurs.");            System.out.println( e.getMessage() );        }        catch (Exception e)        {            valid = false;            System.out.println(errorMsg + "Error occurs.");            System.out.println( e.getMessage() );        }        return valid;    }    /**     * Moves a Gridlet to the destination GridResource ID     * @param gl   a Gridlet object     * @param srcId   the GridResource ID that is currently executing this Gridlet     * @param destId  the new GridResource ID     * @param delay   simulation delay     * @return <tt>true</tt> if this Gridlet has moved successfully,     *         <tt>false</tt> otherwise. Moving a Gridlet can be failed, due     *         to one or more following reasons:     *      <ul>     *         <li> if a Gridlet object is null     *         <li> if one or both GridResource ID don't exist     *         <li> if the delay is negative     *         <li> if a Gridlet in the GridResource has completed beforehand.     *              The Gridlet can be retrieved by using     *              {@link #gridletReceive()}     *      </ul>     * @pre gl != null     * @pre srcId > 0     * @pre destId > 0     * @pre delay >= 0.0     * @post $result = true || false     */    protected boolean gridletMove(Gridlet gl,int srcId,int destId,double delay)    {        if (gl == null || delay < 0.0) {            return false;        }        boolean success = gridletMove(gl.getGridletID(), gl.getUserID(),                                      srcId, destId, delay, true);        return success;    }    /**     * Moves a Gridlet to the destination GridResource ID     * @param gridletId   a Gridlet ID     * @param userId      the owner or user ID of this Gridlet     * @param srcId   the GridResource ID that is currently executing this     *                Gridlet     * @param destId  the new GridResource ID     * @param delay   simulation delay     * @param ack   an acknowledgement, i.e. <tt>true</tt> if wanted to know     *        whether this operation is success or not, <tt>false</tt>     *        otherwise (don't care)     * @return <tt>true</tt> if this Gridlet has moved successfully,     *         <tt>false</tt> otherwise. Moving a Gridlet can be failed, due     *         to one or more following reasons:     *      <ul>     *         <li> if a Gridlet ID doesn't exist     *         <li> if the owner of user ID of this Gridlet doesn't exist     *         <li> if one or both GridResource ID don't exist     *         <li> if the delay is negative     *         <li> if a Gridlet in the GridResource has completed beforehand.     *              The Gridlet can be retrieved by using     *              {@link #gridletReceive()}     *      </ul>     * @pre gridletId > 0     * @pre userId > 0     * @pre srcId > 0     * @pre destId > 0     * @pre delay >= 0.0     * @post $result = true || false     */    protected boolean gridletMove(int gridletId, int userId, int srcId,                                  int destId, double delay, boolean ack)    {        String errorMsg = super.get_name() + ".gridletMove(): ";        // check whether the source Id is the same as destination Id        if (srcId == destId)        {            System.out.println(errorMsg + "Error - Can't move a