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SSJ is a Java library for stochastic simulation, developed under the direction of Pierre L'Ecuyer,
in the Département d'Informatique et de Recherche Opérationnelle (DIRO), at the Université de Montréal.
It provides facilities for generating uniform and nonuniform random variates, computing different
measures related to probability distributions, performing goodness-of-fit tests, applying quasi-Monte
Carlo methods, collecting (elementary) statistics, and programming discrete-event simulations with both
events and processes.
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/*
* Class: EventList
* Description: interface for implementations of event lists
* Environment: Java
* Software: SSJ
* Copyright (C) 2001 Pierre L'Ecuyer and Université de Montréal
* Organization: DIRO, Université de Montréal
* @author
* @since
* SSJ is free software: you can redistribute it and/or modify it under
* the terms of the GNU General Public License (GPL) as published by the
* Free Software Foundation, either version 3 of the License, or
* any later version.
* SSJ 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 General Public License for more details.
* A copy of the GNU General Public License is available at
GPL licence site.
*/
package umontreal.iro.lecuyer.simevents.eventlist;
import java.util.ListIterator;
import umontreal.iro.lecuyer.simevents.Event;
/**
* An interface for implementations of event lists.
* Different implementations are provided in SSJ:
* doubly-linked list, splay tree, Henricksen's method, etc.
* The events in the event list are objects of the class
* {@link umontreal.iro.lecuyer.simevents.Event Event}.
* The method {@link umontreal.iro.lecuyer.simevents.Sim#init(EventList) Sim.init}
* permits one to select
* the actual implementation used in a simulation.
*
*
* To allow the user to print the event list, the
* {@link java.lang.Object#toString toString} method
* from the {@link Object} class should be reimplemented in all EventList
* implementations. It will return a string in the following format:
* ``Contents of the event list event list class:'' for the first line and
* each subsequent line has format
* ``scheduled event time, event priority : event string''.
* The event string is obtained by calling the
* toString method of the event objects.
* The string should not end with the end-of-line character.
*
*
* The following example is the event list of the bank example,
* printed at 10h30. See examples.pdf for more information.
*
*
*
* Contents of the event list SplayTree:
* 10.51, 1 : BankEv$Arrival@cfb549
* 10.54, 1 : BankEv$Departure@8a7efd
* 11, 1 : BankEv$3@86d4c1
* 14, 1 : BankEv$4@f9f9d8
* 15, 1 : BankEv$5@820dda
*
*
*/
public interface EventList extends Iterable {
/**
* Returns true if and only if the event list is empty
* (no event is scheduled).
*
* @return true if the event list is empty
*
*/
public boolean isEmpty();
/**
* Empties the event list, i.e., cancels all events.
*
*/
public void clear();
/**
* Adds a new event in the event list, according to
* the time of ev.
* If the event list contains events scheduled to happen at the same time as
* ev, ev must be added after all these events.
*
* @param ev event to be added
*
*
*/
public void add (Event ev);
/**
* Adds a new event at the beginning of the event list. The given
* event ev will occur at the current simulation time.
*
* @param ev event to be added
*
*
*/
public void addFirst (Event ev);
/**
* Same as {@link #add add}, but adds the new event ev
* immediately before the event other in the list.
*
* @param ev event to be added
*
* @param other reference event before which ev will be added
*
*
*/
public void addBefore (Event ev, Event other);
/**
* Same as {@link #add add}, but adds the new event ev
* immediately after the event other in the list.
*
* @param ev event to be added
*
* @param other reference event after which ev will be added
*
*
*/
public void addAfter (Event ev, Event other);
/**
* Returns the first event in the event list.
* If the event list is empty, returns null.
*
* @return the first event in the event list, or null if the list is empty
*
*/
public Event getFirst();
/**
* Returns the first event of the class cl (a subclass of
* Event) in the event list. If no such event is found, returns
* null.
*
* @return the first event of class cl, or null if no such event exists in the list
*
*/
public Event getFirstOfClass (String cl);
/**
* Returns the first event of the class E (a subclass of
* Event) in the event list. If no such event is found, returns
* null.
*
* @return the first event of class cl, or null if no such event exists in the list
*
*/
public E getFirstOfClass (Class cl);
/**
* Returns a list iterator over the elements of the class Event in this list.
*
* @return a list iterator over the elements of the class Event in this list
*
*/
public ListIterator listIterator();
/**
* Removes the event ev from the event list (cancels this event).
* Returns true if and only if the event removal has succeeded.
*
* @param ev event to be removed
*
* @return true if the event was successfully removed from the list
*
*/
public boolean remove (Event ev);
/**
* Removes the first event from the event list (to cancel or
* execute this event). Returns the removed event. If the list is empty,
* then null is returned.
*
* @return the first event removed from the list, or null if the list is empty
*
*/
public Event removeFirst();
}