--- /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.dynamics;
+
+import peersim.config.*;
+import peersim.core.*;
+import peersim.graph.*;
+
+/**
+* This class contains the implementation of the Barabasi-Albert model
+* of growing scale free networks. The original model is described in
+* <a href="http://arxiv.org/abs/cond-mat/0106096">http://arxiv.org/abs/cond-mat/0106096</a>. It also contains the option of building
+* a directed network, in which case the model is a variation of the BA model
+* described in <a href="http://arxiv.org/pdf/cond-mat/0408391">
+http://arxiv.org/pdf/cond-mat/0408391</a>. In both cases, the number of the
+* initial set of nodes is the same as the degree parameter, and no links are
+* added. The first added node is connected to all of the initial nodes,
+* and after that the BA model is used normally.
+* @see GraphFactory#wireScaleFreeBA
+*/
+public class WireScaleFreeBA extends WireGraph {
+
+
+// ================ constants ============================================
+// =======================================================================
+
+/**
+ * The number of edges added to each new node (apart from those forming the
+ * initial network).
+ * Passed to {@link GraphFactory#wireScaleFreeBA}.
+ * @config
+ */
+private static final String PAR_DEGREE = "k";
+
+
+// =================== fields ============================================
+// =======================================================================
+
+/** Parameter of the BA model. */
+private int k;
+
+// ===================== initialization ==================================
+// =======================================================================
+
+/**
+ * Standard constructor that reads the configuration parameters.
+ * Invoked by the simulation engine.
+ * @param prefix the configuration prefix for this class
+*/
+public WireScaleFreeBA(String prefix)
+{
+ super(prefix);
+ k = Configuration.getInt(prefix + "." + PAR_DEGREE);
+}
+
+
+// ======================== methods =======================================
+// ========================================================================
+
+
+/** calls {@link GraphFactory#wireScaleFreeBA}.*/
+public void wire(Graph g) {
+
+ GraphFactory.wireScaleFreeBA(g,k,CommonState.r );
+}
+
+}
+
