--- /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.vector;
+
+import peersim.config.*;
+import peersim.core.*;
+import peersim.util.*;
+
+/**
+* Print statistics over a vector. The vector is defined by a protocol,
+* specified by {@value #PAR_PROT}, that has to implement
+* {@link SingleValue}.
+* Statistics printed are: min, max, number of samples, average, variance,
+* number of minimal instances, number of maximal instances (using
+* {@link IncrementalStats#toString}).
+* @see IncrementalStats
+*/
+public class SingleValueObserver implements Control {
+
+
+//--------------------------------------------------------------------------
+//Parameters
+//--------------------------------------------------------------------------
+
+/**
+ * The parameter used to determine the accuracy
+ * (standard deviation) before stopping the simulation. If not
+ * defined, a negative value is used which makes sure the observer
+ * does not stop the simulation.
+ * @see #execute
+ * @config
+ */
+private static final String PAR_ACCURACY = "accuracy";
+
+/**
+ * The protocol to operate on.
+ * @config
+ */
+private static final String PAR_PROT = "protocol";
+
+
+//--------------------------------------------------------------------------
+// Fields
+//--------------------------------------------------------------------------
+
+/** The name of this observer in the configuration */
+private final String name;
+
+/** Accuracy for standard deviation used to stop the simulation */
+private final double accuracy;
+
+/** Protocol identifier */
+private final int pid;
+
+
+//--------------------------------------------------------------------------
+// Constructor
+//--------------------------------------------------------------------------
+
+/**
+ * Standard constructor that reads the configuration parameters.
+ * Invoked by the simulation engine.
+ * @param name the configuration prefix for this class
+ */
+public SingleValueObserver(String name)
+{
+ this.name = name;
+ accuracy = Configuration.getDouble(name + "." + PAR_ACCURACY, -1);
+ pid = Configuration.getPid(name + "." + PAR_PROT);
+}
+
+
+//--------------------------------------------------------------------------
+// Methods
+//--------------------------------------------------------------------------
+
+/**
+* Print statistics over a vector. The vector is defined by a protocol,
+* specified by {@value #PAR_PROT}, that has to implement
+* {@link SingleValue}.
+* Statistics printed are: min, max, number of samples, average, variance,
+* number of minimal instances, number of maximal instances (using
+* {@link IncrementalStats#toString}).
+* @return true if the standard deviation is below the value of
+ * {@value #PAR_ACCURACY}, and the time of the simulation is larger then zero
+ * (i.e. it has started).
+ */
+public boolean execute()
+{
+ IncrementalStats stats = new IncrementalStats();
+
+ /* Compute max, min, average */
+ for (int i = 0; i < Network.size(); i++)
+ {
+ SingleValue v = (SingleValue)Network.get(i).getProtocol(pid);
+ stats.add( v.getValue() );
+ }
+
+ /* Printing statistics */
+ System.out.println(name+": "+stats);
+
+ /* Terminate if accuracy target is reached */
+ return (stats.getStD()<=accuracy && CommonState.getTime()>0);
+}
+
+//--------------------------------------------------------------------------
+
+}
