/*  * Copyright (c) 2000 by Matt Welsh and The Regents of the University of  * California. All rights reserved. * * Permission to use, copy, modify, and distribute this software and its * documentation for any purpose, without fee, and without written agreement is * hereby granted, provided that the above copyright notice and the following * two paragraphs appear in all copies of this software. *  * IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY FOR * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT * OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF THE UNIVERSITY OF * CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. *  * THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES, * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY * AND FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS * ON AN "AS IS" BASIS, AND THE UNIVERSITY OF CALIFORNIA HAS NO OBLIGATION TO * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS. * * Author: Matt Welsh <mdw@cs.berkeley.edu> *  */package ninja2.core.io_core.nbio;/** * A SelectItem represents a single socket/file descriptor/etc. which * can be handled by a SelectSet. Each SelectItem has an associated * Selectable as well as two event masks: 'events' and 'revents'. * Setting 'events' allows you to specify which events you are * interested in receiving notification on for this Selectable. * After calling SelectSet.select(), 'revents' will be set to the * set of events that occurred.  */public class SelectItem {  private Selectable sel; // Do not let user change this without updating fd  /**   * The set of events that you are interested in receiving notification on.   * The event types are specified by the constants in Selectable.   *   * <p><b>Important:</b> If you change the events field of a SelectItem   * after registering it with a SelectSet (using SelectSet.add()),    * you must invoke SelectSet.update() to push the new event mask to the   * SelectSet.   *   * @see Selectable   * @see SelectSet   */  public short events;  /**   * The set of events that occurred.   * The event types are specified by the constants in Selectable.   * @see Selectable   */  public short revents;  /**    * A state object associated with this SelectItem. You can use this   * for any purpose you like.   */  public Object obj;  private NBIOFileDescriptor fd;  private void updatefd() {    // We want to keep a clone of the fd here, since if the socket     // closes, we want to remember the fd for deregistering with SelectSet.    if (sel instanceof NonblockingSocket) {      fd = ((NonblockingSocket)sel).impl.getFileDescriptor().getClone();    } else if (sel instanceof NonblockingServerSocket) {      fd = ((NonblockingServerSocket)sel).impl.getFileDescriptor().getClone();    } else {      throw new IllegalArgumentException("Selectable must support internal NBIOFileDescriptor");    }  }  // So SelectSet can get fd  NBIOFileDescriptor getFD() {    return fd;  }  /**   * Create a SelectItem with the given Selectable, given state pointer,   * and the given event mask.   */  public SelectItem(Selectable sel, Object obj, short events) {    this.sel = sel;    this.obj = obj;    this.events = events;    this.revents = (short)0;    updatefd();  }  /**   * Create a SelectItem with the given Selectable and the given event   * mask.   */  public SelectItem(Selectable sel, short events) {    this(sel, null, events);  }  /**   * Return the Selectable associated with this SelectItem.   */  public Selectable getSelectable() {    return sel;  }  /**   * Return the state pointer associated with this SelectItem.   */  public Object getObj() {    return obj;  }  /**   * Return the requested events mask.   */  public short getEvents() {    return events;  }  /**   * Return the returned events mask.   */  public short returnedEvents() {    return revents;  }  public String toString() {    return "SelectItem [sel="+sel+"] events=0x"+Integer.toHexString(events)+" revents=0x"+Integer.toHexString(revents);  }  }