/* * Title:        GridSim Toolkit * Description:  GridSim (Grid Simulation) Toolkit for Modeling and Simulation *               of Parallel and Distributed Systems such as Clusters and Grids * Licence:      GPL - http://www.gnu.org/copyleft/gpl.html * * $Id: FilterQueryTimeAR.java,v 1.2 2005/03/10 04:35:17 anthony Exp $ */package gridsim.filter;import gridsim.Gridlet;import gridsim.GridSimTags;import eduni.simjava.Sim_predicate;import eduni.simjava.Sim_event;/** * Look for a specific incoming event that matches a given event tag name and a * transaction id. Incoming events with a matching tag name <b>must</b> * contain a data object of type * <tt>Object[]</tt>, where <tt>Object[0]</tt> stores the transaction id.<br> * <tt>NOTE:</tt> This class can only be used for getting a reply or feedback * from a {@link gridsim.ARGridResource} entity regarding to query free or * busy time of a reservation. * <br><br> * * This class is used by {@link eduni.simjava.Sim_system} * to select or filter an event already present in the entity's deferred queue * (incoming buffer), or used to selectively wait for a future event. * <br> <br> * * <b>An example on how to use this class:</b><br> * Imagine we have a scenario where <tt>RESOURCE_A</tt> sends one or more events * to <tt>Entity_B</tt> with different tag names and data objects.<br> * <tt>Entity_B</tt> wants to get an event that contains a query reservation * time result with a transaction id of <tt>10</tt> in this example. <br> * Therefore, inside the <tt>Entity_B</tt> code:<br> <br> * * <code> * * &nbsp;&nbsp; ... // other code <br><br> * &nbsp;&nbsp; int transactionID = 10; <br> * &nbsp;&nbsp; Sim_event ev = new Sim_event(); <br> * &nbsp;&nbsp; FilterQueryTimeAR filter = new FilterQueryTimeAR(transactionID); <br> * <br> * &nbsp;&nbsp; // get an incoming event that matches a given transaction ID<br> * &nbsp;&nbsp; super.sim_get_next(filter, ev); <br> * <br> * &nbsp;&nbsp; // get the matching event data, where *                 data[0] contains transaction ID <br> * &nbsp;&nbsp; // (in Integer object) <br> * &nbsp;&nbsp; Object[] data = (Object[]) ev.get_data(); * </code> * <br><br> * * <b>NOTE:</b> * <ul> * <li> both <tt>RESOURCE_A</tt> and <tt>Entity_B</tt> must be an instance of *      {@link eduni.simjava.Sim_entity} class. * <li> <tt>RESOURCE_A</tt> <b>must</b> send the correct data object to *      <tt>Entity_B</tt> for events with a matching tag name. <br> *      The event data object with a matching tag name *      <b>must</b> be of type <tt>Object[]</tt>, where *      <tt>Object[0]</tt> contains the transaction id. * <li> if no incoming events match the given condition, then *      {@link eduni.simjava.Sim_entity#sim_get_next(Sim_predicate, Sim_event)} *      method will wait indefinitely. * </ul> * * @author       Anthony Sulistio * @since        GridSim Toolkit 3.2 * @invariant $none */public class FilterQueryTimeAR extends Sim_predicate{    private int tag_;    private int eventID_;    /**     * Finds an incoming events that matches with the given transaction ID and     * event tag name.     * @param transactionID   a unique transaction ID to differentiate     *                        itself among other events with the same tag name     * @param tag   a matching event tag name     * @pre $none     * @post $none     */    public FilterQueryTimeAR(int transactionID, int tag)    {        tag_ = tag;        eventID_ = transactionID;    }    /**     * Finds an incoming events that matches with the given transaction ID and     * a default tag name of {@link GridSimTags#RETURN_AR_QUERY_TIME}.     * @param transactionID   a unique transaction ID to differentiate     *                        itself among other events with the same tag name     * @pre $none     * @post $none     */    public FilterQueryTimeAR(int transactionID)    {        tag_ = GridSimTags.RETURN_AR_QUERY_TIME;        eventID_ = transactionID;    }    /**     * Checks whether an event matches the required constraints or not.<br>     * NOTE: This method is not used directly by the user. Instead, it is     * called by {@link eduni.simjava.Sim_system}.     *     * @param ev    an incoming event to compare with     * @return <tt>true</tt> if an event matches, <tt>false</tt> otherwise     * @pre ev != null     * @post $none     */    public boolean match(Sim_event ev)    {        if (ev == null) {            return false;        }        boolean result = false;        try        {            // find an event with a matching tag first            if ( tag_ == ev.get_tag() )            {                Object obj = ev.get_data();                // if the event's data contains the correct data                if (obj instanceof Object[])                {                    Object[] array = (Object[]) obj;                    // if the data contains the correct ID or value                    Integer intObj = (Integer) array[0];                    if (intObj.intValue() == eventID_) {                        result = true;                    }                }            }        }        catch (Exception e) {            result = false;        }        return result;    }} // end class