--- /dev/null
+/*
+ * Copyright (c) 2003-2005 The BISON Project
+ *
+ * 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.reports;
+
+import java.util.Iterator;
+import java.util.Map;
+import peersim.config.Configuration;
+import peersim.util.IncrementalStats;
+
+/**
+ * Reports statistics about connectivity properties of the network, such as
+ * weakly or strongly connected clusters.
+ */
+public class ConnectivityObserver extends GraphObserver
+{
+
+//--------------------------------------------------------------------------
+//Parameters
+//--------------------------------------------------------------------------
+
+/**
+ * The parameter used to request cluster size statistics instead of the usual
+ * list of clusters. Not set by default.
+ * @config
+ */
+private static final String PAR_STATS = "stats";
+
+/**
+ * Defines the types of connected clusters to discover.
+ * Possible values are
+ * <ul>
+ * <li>"wcc": weakly connected clusters</li>
+ * <li>"scc": strongly connected clusters</li>
+ * </ul>
+ * Defaults to "wcc".
+ * @config
+ */
+private static final String PAR_TYPE = "type";
+
+//--------------------------------------------------------------------------
+//Fields
+//--------------------------------------------------------------------------
+
+/** {@link #PAR_STATS} */
+private final boolean sizestats;
+
+/** {@link #PAR_TYPE} */
+private final String type;
+
+//--------------------------------------------------------------------------
+//Initialization
+//--------------------------------------------------------------------------
+
+/**
+ * Standard constructor that reads the configuration parameters.
+ * Invoked by the simulation engine.
+ * @param name the configuration prefix for this class
+ */
+public ConnectivityObserver(String name)
+{
+ super(name);
+ sizestats = Configuration.contains(name + "." + PAR_STATS);
+ type = Configuration.getString(name + "." + PAR_TYPE,"wcc");
+}
+
+//--------------------------------------------------------------------------
+//Methods
+//--------------------------------------------------------------------------
+
+/**
+* Prints information about clusters.
+* If parameter {@value #PAR_STATS} is defined then the output is
+* produced by {@link IncrementalStats#toString}, over the sizes of the
+* clusters.
+* Otherwise one line is printed that contains the string representation of
+* a map, that holds cluster IDs mapped to cluster sizes.
+* The meaning of the cluster IDs is not specified, but is printed for
+* debugging purposes.
+* @return always false
+* @see peersim.graph.GraphAlgorithms#tarjan
+* @see peersim.graph.GraphAlgorithms#weaklyConnectedClusters
+*/
+public boolean execute()
+{
+ Map clst;
+ updateGraph();
+
+ if(type.equals("wcc"))
+ clst=ga.weaklyConnectedClusters(g);
+ else if(type.equals("scc"))
+ clst=ga.tarjan(g);
+ else
+ throw new RuntimeException(
+ "Unsupported connted cluster type '"+type+"'");
+
+ if (!sizestats) {
+ System.out.println(name + ": " + clst);
+ } else {
+ IncrementalStats stats = new IncrementalStats();
+ Iterator it = clst.values().iterator();
+ while (it.hasNext()) {
+ stats.add(((Integer) it.next()).intValue());
+ }
+ System.out.println(name + ": " + stats);
+ }
+ return false;
+}
+
+}
