/**
* Copyright (C) 2006, Laboratorio di Valutazione delle Prestazioni - Politecnico di Milano
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
* 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 General Public License for more details.
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
package jmt.engine.NetStrategies.RoutingStrategies;
import jmt.engine.NetStrategies.RoutingStrategy;
import jmt.engine.QueueNet.JobClass;
import jmt.engine.QueueNet.NetNode;
import jmt.engine.QueueNet.NodeList;
/**
* This class implements a round robin strategy: all the output nodes
* are chosen in sequence, one at each time; when all the nodes have been chosen,
* the sequence restarts.
* @author Francesco Radaelli, Bertoli Marco
* Modified by Bertoli Marco to correct behaviour with closed classes and sinks
*/
public class RoundRobinStrategy extends RoutingStrategy {
private int CLOSED_CLASS = JobClass.CLOSED_CLASS;
private int Counter;
public RoundRobinStrategy() {
Counter = 0;
}
/**
* Gets the output node, into which the job must be routed, using a round
* robin strategy.
* @param Nodes the list of output nodes
* @param jobClass class ofcurrent job to be routed
* @return The selected node.
*/
@Override
public NetNode getOutNode(NodeList Nodes, JobClass jobClass) {
NetNode out;
if (Nodes.size() == 0) {
return null;
} else {
if (Counter == Nodes.size()) {
Counter = 0;
}
out = Nodes.get(Counter++);
// Skips sinks for closed classes
if (jobClass.getType() == CLOSED_CLASS) {
int totalLoops = 0; // Counts whenever a full loop has been performed
while (out.isSink()) {
if (Counter == Nodes.size()) {
Counter = 0;
if (totalLoops++ > 0) {
return null;
}
}
out = Nodes.get(Counter++);
}
}
return out;
}
}
}