--- /dev/null
+/*
+ * Copyright (c) 2007-2008 Fabrizio Frioli, Michele Pedrolli
+ *
+ * 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.
+ *
+ * --
+ *
+ * Please send your questions/suggestions to:
+ * {fabrizio.frioli, michele.pedrolli} at studenti dot unitn dot it
+ *
+ */
+
+package example.bittorrent;
+
+import peersim.core.*;
+import peersim.config.Configuration;
+
+/**
+ * This class provides a way to initialize a single node of the network.
+ * The initialization is performed by choosing the bandwidth of the node
+ * and choosing how much the shared file has been downloaded.
+ */
+public class NodeInitializer{
+
+ /**
+ * The protocol to operate on.
+ * @config
+ */
+ private static final String PAR_PROT="protocol";
+
+ /**
+ * The percentage of nodes with no downloaded pieces.
+ * @config
+ * @see "The documentation for an example on how to properly set this parameter."
+ */
+ private static final String PAR_NEWER_DISTR="newer_distr";
+
+ /**
+ * The percentage of seeders in the network.
+ * @config
+ */
+ private static final String PAR_SEEDER_DISTR="seeder_distr";
+
+ /**
+ * The percentage of nodes with no downloaded pieces,
+ * as defined in {@see #PAR_NEWER_DISTR}.
+ */
+ private int newerDistr;
+
+ /**
+ * The percentage of seeder nodes,
+ * as defined in {@see #PAR_SEEDER_DISTR}.
+ */
+ private int seederDistr;
+
+ /**
+ * The BitTorrent protocol ID.
+ */
+ private final int pid;
+
+ /**
+ * The basic constructor of the class, which reads the parameters
+ * from the configuration file.
+ * @param prefix the configuration prefix for this class
+ */
+ public NodeInitializer(String prefix){
+ pid = Configuration.getPid(prefix+"."+PAR_PROT);
+ newerDistr = Configuration.getInt(prefix+"."+PAR_NEWER_DISTR);
+ seederDistr = Configuration.getInt(prefix+"."+PAR_SEEDER_DISTR);
+ }
+
+ /**
+ * Initializes the node <tt>n</tt> associating it
+ * with the BitTorrent protocol and setting the reference to the tracker,
+ * the status of the file and the bandwidth.
+ * @param n The node to initialize
+ */
+ public void initialize(Node n){
+ Node tracker = Network.get(0);
+ BitTorrent p;
+ p = (BitTorrent)n.getProtocol(pid);
+ p.setTracker(tracker);
+ p.setThisNodeID(n.getID());
+ setFileStatus(p);
+ setBandwidth(p);
+ }
+
+ /**
+ * Sets the status of the shared file according to the
+ * probability value given by {@link #getProbability()}.
+ * @param p The BitTorrent protocol
+ */
+ private void setFileStatus(BitTorrent p){
+ int percentage = getProbability();
+ choosePieces(percentage, p);
+ }
+
+ /**
+ * Set the maximum bandwidth for the node, choosing
+ * uniformly at random among 4 values.
+ * <p>
+ * The allowed bandwidth speed are 640 Kbps, 1 Mbps, 2 Mbps and 4 Mbps.
+ * </p>
+ * @param p The BitTorrent protocol
+ */
+ private void setBandwidth(BitTorrent p){
+ int value = CommonState.r.nextInt(4);
+ switch(value){
+ case 0: p.setBandwidth(640);break; //640Kbps
+ case 1: p.setBandwidth(1024);break;// 1Mbps
+ case 2: p.setBandwidth(2048);break;// 2Mbps
+ case 3: p.setBandwidth(4096);break; //4Mbps
+ }
+ }
+
+ /**
+ * Sets the completed pieces for the given protocol <tt>p</tt>.
+ * @parm percentage The percentage of the downloaded pieces, according to {@link #getProbability()}
+ * @param p the BitTorrent protocol
+ */
+ private void choosePieces(int percentage, BitTorrent p){
+ double temp = ((double)p.nPieces/100.0)*percentage; // We use a double to avoid the loss of precision
+ // during the division operation
+ int completed = (int)temp; //integer number of piece to set as completed
+ //0 if the peer is a newer
+ p.setCompleted(completed);
+ if(percentage == 100)
+ p.setPeerStatus(1);
+ int tmp;
+ while(completed!=0){
+ tmp = CommonState.r.nextInt(p.nPieces);
+ if(p.getStatus(tmp)!=16){
+ p.setStatus(tmp, 16);
+ completed--;
+ }
+ }
+ }
+
+ /**
+ * Gets a probability according with the parameter <tt>newer_distr</tt>
+ * defined in the configuration file.
+ * @return the probabilty value, where 0 means that the peer is new and no pieces has been downloaded,
+ * 100 means that the peer is a seeder; other values defines a random probability.
+ * @see #PAR_NEWER_DISTR
+ */
+ private int getProbability(){
+ int value = CommonState.r.nextInt(100);
+ if((value+1)<=seederDistr)
+ return 100;
+ value = CommonState.r.nextInt(100);
+ if((value+1)<=newerDistr){
+ return 0; // A newer peer, with probability newer_distr
+ }
+ else{
+ value = CommonState.r.nextInt(9);
+ return (value+1)*10;
+ }
+ }
+}
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