--- /dev/null
+/*
+ * Copyright (c)2008 The Peersim Team
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program 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 Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ */
+
+package peersim.edsim;
+
+import peersim.core.Node;
+
+/**
+ * The interface to be implemented by the event queue of the evend based
+ * engine. An implementation must also provide the standard cosntructor
+ * required by any peersim components: one that takes a String argument,
+ * the component name in the configuration.
+ */
+public interface PriorityQ {
+
+
+/**
+ * Returns the current number of events in the queue.
+ */
+public int size();
+
+/**
+ * Add a new event, to be scheduled at the specified time. If there are other
+ * events scheduled at the same time, then the time of execution if this event
+ * relative to the other events is unspecified.
+ *
+ * @param time The time at which this event should be scheduled. It is
+ * guaranteed to be non-negative (so no extra checks are needed)
+ * @param event the object describing the event
+ * @param node the node at which the event has to be delivered
+ * @param pid the protocol that handles the event
+ */
+public void add(long time, Object event, Node node, byte pid);
+
+/**
+ * Add a new event, to be scheduled at the specified time, specifying also
+ * the priority of the event, should there be other events scheduled at the
+ * same time. If both time and priority is the same for an event, then the
+ * scheduling order is unspecified.
+ *
+ * @param time The time at which this event should be scheduled. It is
+ * guaranteed to be non-negative (so no extra checks are needed)
+ * @param event the object describing the event
+ * @param node the node at which the event has to be delivered
+ * @param pid the protocol that handles the event
+ * @param priority if for two events the "time" value is the same, this
+ * value should be used to order them. Lower value means higher priority.
+ * Like with time, non-negativity as assumed.
+ */
+public void add(long time, Object event, Node node, byte pid, long priority);
+
+/**
+ * Removes the first event in the heap and returns it.
+ * The returned object is not guaranteed to be a freshly generated object,
+ * that is, we allow for an implementation that keeps one copy of an event
+ * object and always returns a reference to that copy.
+ * @return first event or null if size is zero
+ */
+public Event removeFirst();
+
+/**
+* Maximal value of time this interpretation can represent.
+*/
+public long maxTime();
+
+/**
+* Maximal value of priority this interpretation can deal with. That is,
+* the number of different priority levels is <tt>maxPriority()+1</tt> because
+* 0 is also a valid level.
+* @see #add(long,Object,Node,byte,long)
+*/
+public long maxPriority();
+
+/**
+ * Return type of {@link #removeFirst()}.
+ */
+public class Event
+{
+ public Object event;
+ public long time;
+ public Node node;
+ public byte pid;
+ public String toString() {
+ return event+" to node "+node+"prot "+pid+"at "+time; }
+}
+
+}
