/* * 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 */package gridsim.datagrid.filter;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 * logical file name (lfn). 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 lfn. * <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>Entity_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 with a <tt>HIGH_PRIORITY</tt> tag * and a lfn of <tt>Data01</tt> in this example. <br> * Therefore, inside the <tt>Entity_B</tt> code:<br> <br> * * <code> * * &nbsp;&nbsp; ... // other code <br><br> * &nbsp;&nbsp; String lfn = "Data01"; <br> * &nbsp;&nbsp; int tag = HIGH_PRIORITY; <br> * &nbsp;&nbsp; Sim_event ev = new Sim_event(); <br> * &nbsp;&nbsp; FilterDataResult filter = new FilterDataResult(lfn, tag); <br> * <br> * &nbsp;&nbsp; // get an incoming event that matches a given filter <br> * &nbsp;&nbsp; super.sim_get_next(filter, ev); <br> * <br> * &nbsp;&nbsp; // get the matching event data <br> * &nbsp;&nbsp; Object[] result = (Object[]) ev.get_data(); <br> * </code> * <br><br> * * <b>NOTE:</b> * <ul> * <li> both <tt>Entity_A</tt> and <tt>Entity_B</tt> must be an instance of *      {@link eduni.simjava.Sim_entity} class. * <li> <tt>Entity_A</tt> <b>must</b> send the correct data object to *      <tt>Entity_B</tt> for this type of filtering. <br> *      The event data object <b>must</b> be of type <tt>Object[]</tt>. * <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  Uros Cibej and Anthony Sulistio * @since   GridSim Toolkit 4.0 */public class FilterDataResult extends Sim_predicate {    private int tag_;       // a tag name    private String lfn_;    // logical file name    /**     * Creates a new filter to select an incoming event based     * on the logical file name (lfn) and tag name     * @param lfn   the logical file name     * @param tag   a matching event tag name     */    public FilterDataResult(String lfn, int tag) {        tag_ = tag;        lfn_ = lfn;    }    /**     * 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     */    public boolean match(Sim_event ev) {        // checks for errors first        if (ev == null || lfn_ == null) {            return false;        }        boolean result = false;        try {            // find an event with a matching tag first            if (ev.get_tag() == tag_) {                Object obj = ev.get_data();     // get the data                // if the event's data contains the correct data                if (obj instanceof Object[]) {                    Object[] array = (Object[]) obj;                    String name = (String) array[0];                    // if the data contains the correct ID or value                    if (lfn_.equals(name) == true) {                        result = true;                    }                }            }        }        catch (Exception e) {            result = false;        }        return result;    }} // end class