/*
VisAD system for interactive analysis and visualization of numerical
data.  Copyright (C) 1996 - 2017 Bill Hibbard, Curtis Rueden, Tom
Rink, Dave Glowacki, Steve Emmerson, Tom Whittaker, Don Murray, and
Tommy Jasmin.

This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
Library General Public License for more details.

You should have received a copy of the GNU Library General Public
License along with this library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
MA 02111-1307, USA
*/

package visad.collab;

import java.io.Serializable;

import java.rmi.RemoteException;

import visad.Control;
import visad.ControlListener;
import visad.DisplayListener;
import visad.MessageListener;
import visad.RemoteDisplay;
import visad.RemoteVisADException;
import visad.ScalarMapListener;
import visad.VisADException;

/**
 * <CODE>DisplayMonitor</CODE> is the interface for objects which monitor
 * the state of <CODE>Control</CODE>s, <CODE>Display</CODE>s and
 * <CODE>ScalarMap</CODE>s.
 */
public interface DisplayMonitor
  extends ControlListener, DisplayListener, MessageListener,
          ScalarMapListener, Serializable
{
  /** Connection ID used to indicate errors */
  int UNKNOWN_LISTENER_ID = 0;

  /**
   * Adds the specified listener to receive <CODE>MonitorEvent</CODE>s
   * when the monitored <CODE>Display</CODE>'s state changes.
   *
   * @param callback The object to which events are delivered.
   * @param id The unique identifier.
   *
   * @exception RemoteException If there was an RMI-related problem.
   * @exception VisADException If the listener <CODE>Vector</CODE>
   * 				is uninitialized.
   */
  void addListener(MonitorCallback callback, int id)
    throws RemoteException, VisADException;

  /**
   * Adds the specified remote display to receive <CODE>MonitorEvent</CODE>s
   * when the monitored <CODE>Display</CODE>'s state changes.
   *
   * @param rd The remote display to add.
   * @param id The unique listener identifier.
   *
   * @exception RemoteException If there was an RMI-related problem.
   * @exception VisADException If the listener <CODE>Vector</CODE>
   * 				is uninitialized.
   */
  void addListener(RemoteDisplay rd, int id)
    throws RemoteException, VisADException;

  /**
   * Initializes links so that <CODE>MonitorEvent</CODE>s will be
   * exchanged with the specified remote <CODE>Display</CODE>.
   *
   * @param rd The remote <CODE>Display</CODE> to synchronize.
   *
   * @exception RemoteException If there was an RMI-related problem.
   * @exception RemoteVisADException If the inter-<CODE>Display</CODE>
   * 					links could not be made.
   */
  void addRemoteListener(RemoteDisplay rd)
    throws RemoteException, RemoteVisADException;

  /**
   * Returns a suggestion for a unique listener identifier which is
   * equal to or greater than the supplied ID.
   *
   * @param id The identifier to check.
   *
   * @exception RemoteException If there was an RMI-related problem.
   */
  int checkID(int id)
    throws RemoteException;

  /** destroy this monitor */
  void destroy()
    throws RemoteException, RemoteVisADException;

  /**
   * Return the ID associated with the specified <tt>RemoteDisplay</tt>.
   *
   * @return <tt>UNKNOWN_LISTENER_ID</tt> if not found;
   *         otherwise, returns the ID.
   */
  int getConnectionID(RemoteDisplay rmtDpy)
    throws RemoteException;

  /**
   * Returns <CODE>true</CODE> if there is a <CODE>MonitorEvent</CODE>
   * for the specified <CODE>Control</CODE> waiting to be delivered to
   * any listener.
   *
   * @param ctl The <CODE>Control</CODE> being found.
   *
   * @exception RemoteException If there was an RMI-related problem.
   */
  boolean hasEventQueued(Control ctl)
    throws RemoteException;

  /**
   * Returns <CODE>true</CODE> if there is a <CODE>MonitorEvent</CODE>
   * for the specified <CODE>Control</CODE> waiting to be delivered to the
   * listener with the specified id.
   *
   * @param listenerID The identifier for the listener.
   * @param ctl The <CODE>Control</CODE> being found.
   *
   * @exception RemoteException If there was an RMI-related problem.
   */
  boolean hasEventQueued(int listenerID, Control ctl)
    throws RemoteException;

  // WLH 12 April 2001
  boolean isEmpty()
    throws RemoteException;

  /**
   * Forwards the <CODE>MonitorEvent</CODE> to all the listeners
   * associated with this <CODE>DisplayMonitor</CODE>.
   *
   * @param evt The event to forward.
   *
   * @exception RemoteException If there was an RMI-related problem.
   * @exception RemoteVisADException If there is an internal error.
   */
  void notifyListeners(MonitorEvent evt)
    throws RemoteException, RemoteVisADException;

  /**
   * Set the display synchronization object for this display
   */
  void setDisplaySync(DisplaySync sync)
    throws RemoteException;
}