/**
* 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.common.exception.IncorrectDistributionParameterException;
import jmt.common.exception.LoadException;
import jmt.engine.NetStrategies.RoutingStrategy;
import jmt.engine.QueueNet.JobClass;
import jmt.engine.QueueNet.NetNode;
import jmt.engine.QueueNet.NetSystem;
import jmt.engine.QueueNet.NodeList;
import jmt.engine.random.Empirical;
import jmt.engine.random.EmpiricalEntry;
import jmt.engine.random.EmpiricalPar;
/**
* The node, into which job must be routed, is chosen using an empirical strategy.
* An empirical strategy is based on an empirical distribution, that is a
* distribution constructed from the data provided by the user.
*
* @author Federico Granata, Stefano Omini, Bertoli Marco
*/
public class EmpiricalStrategy extends RoutingStrategy {
private int CLOSED_CLASS = JobClass.CLOSED_CLASS;
// Used to terminate the loop to avoid to send a job of closed class into a sink
// By the way a check is implemented at gui level, so this condition will never apply.
private final int maxSinkTry = 4096;
//the empirical distribution
private Empirical distribution;
//the parameter of the empirical distribution
private EmpiricalPar param;
//the array with the routing probabilities (one for each output node)
private double probabilities[];
//the NetNode objects corresponding to the output nodes
private NetNode[] nodes;
//the names of the output nodes
private String[] nodeNames;
/**
* Creates an empirical strategy by adding nodes and naming them with the specified names.
* @param distribution The empirical distribution
* @param param The parameters of the empirical distribution
* @throws LoadException
*/
public EmpiricalStrategy(Empirical distribution, EmpiricalPar param) throws LoadException {
this.distribution = distribution;
this.param = param;
//gets the values contained in the empirical parameter (in this case these
//objects are the names of the output nodes)
Object[] names = param.getValues();
nodeNames = new String[names.length];
//OLD
//nodes = new NetNode[names.length];
//NEW
//@author Stefano Omini
for (int i = 0; i < names.length; i++) {
if (names[i] instanceof String) {
//sets the name of the i-th output node
nodeNames[i] = (String) names[i];
//OLD
//this reserach of the NetNode gives an error if the owner node of this
//strategy is inserted before the output nodes referred to in the strategy
//For this reason, at this point only nodeNames information are stored.
//The NetNode objects will be found later by the findNodes() method.
//sets the NetNode reference to the i-th output node (found
//using its name)
//nodes[i] = NetSystem.getNode(nodeNames[i]);
//end OLD
} else {
throw new LoadException("Name of the node is not a String");
}
}
}
/**
* Creates an empirical strategy using the passed data.
* @param entries Entries used to construct the empirical distribution (each entry
* contains a node name and the corresponding routing probability).
* @throws LoadException
* @throws IncorrectDistributionParameterException
*/
public EmpiricalStrategy(EmpiricalEntry[] entries) throws LoadException, IncorrectDistributionParameterException {
probabilities = new double[entries.length];
//OLD
//nodes = new NetNode[entries.length];
//NEW
//@author Stefano Omini
nodeNames = new String[entries.length];
//end NEW
for (int i = 0; i < entries.length; i++) {
EmpiricalEntry entry = entries[i];
if (entry.getValue() instanceof String) {
//gets the value contained in the empirical entry (in this case this
//object is the name of the output node)
String nodeName = (String) entry.getValue();
//sets the name of the node; the corresponding NetNode object will be found later
nodeNames[i] = nodeName;
//sets the corresponding routing probability
probabilities[i] = entry.getProbability();
} else {
throw new LoadException("Name of the node is not a String");
}
}
//uses the obtained probabilities to create the empirical distribution
//and its parameter
distribution = new Empirical();
param = new EmpiricalPar(probabilities);
}
/**
* It controls whether the distribution is correct or not.
* For the empirical distribution, the parameter is correct if the sum of the
* routing probabilities are greater than zero and they sum to 1.0.
*/
@Override
public boolean check() {
return param.check();
}
/**
* Gets the output node, into which the job must be routed, using an
* empirical strategy.
* @param nodeList the list of output nodes
* @param jobClass class ofcurrent job to be routed
* @return The selected node.
*/
@Override
public NetNode getOutNode(NodeList nodeList, JobClass jobClass) {
try {
if (nodes == null) {
//it's the first execution of this method: find the NetNode objects
//corresponding to the nodeNames
findNodes();
}
//the empirical distribution returns the position of the chosen output node
int nodePos = (int) distribution.nextRand(param);
NetNode node = this.nodes[nodePos];
// Controls if a closed class job is put into a sink - Bertoli Marco
if (jobClass.getType() == CLOSED_CLASS) {
// when reaches maxSinkTry, aborts this strategy returning null
int tries = 0;
while (node.isSink()) {
if (tries++ >= maxSinkTry) {
return null;
}
// Try to find a node different from a sink
nodePos = (int) distribution.nextRand(param);
node = this.nodes[nodePos];
}
}
if (nodeList.contains(node)) {
//the chosen node must be contained in the list of the output nodes
return node;
}
} catch (IncorrectDistributionParameterException e) {
e.printStackTrace();
}
return null;
}
//NEW
//@author Stefano Omini
/**
* Finds the NetNode objects corresponding to the node names received by constructor.
* @return true if all names actually correspond to nodes of the model, false otherwise;
*/
private boolean findNodes() {
nodes = new NetNode[nodeNames.length];
for (int i = 0; i < nodeNames.length; i++) {
nodes[i] = NetSystem.getNode(nodeNames[i]);
if (nodes[i] == null) {
//the passed name does not correspond to a node of the model
return false;
}
}
return true;
}
//end NEW
}