+++ /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.edsim;
-
-import peersim.core.*;
-import peersim.cdsim.CDProtocol;
-import peersim.config.*;
-import peersim.dynamics.NodeInitializer;
-
-/**
- * Schedules the first execution of the cycle based protocol instances in the
- * event driven engine. It implements {@link Control} but it will most often be
- * invoked only once for each protocol as an initializer, since the scheduled
- * events schedule themselves for the consecutive executions (see
- * {@link NextCycleEvent}).
- *
- * <p>
- * All {@link CDProtocol} specifications in the configuration need to contain a
- * {@link Scheduler} specification at least for the step size (see config
- * parameter {@value peersim.core.Scheduler#PAR_STEP} of {@link Scheduler}).
- * This value is used as the cycle length for the corresponding protocol.
- *
- * @see NextCycleEvent
- */
-public class CDScheduler implements Control, NodeInitializer {
-
- // ============================== fields ==============================
- // ====================================================================
-
- /**
- * Parameter that is used to define the class that is used to schedule the
- * next cycle. Its type is (or extends) {@link NextCycleEvent}. Defaults to
- * {@link NextCycleEvent}.
- *
- * @config
- */
- private static final String PAR_NEXTC = "nextcycle";
-
- /**
- * The protocols that this scheduler schedules for the first execution. It
- * might contain several protocol names, separated by whitespace. All
- * protocols will be scheduled based on the common parameter set for this
- * scheduler and the parameters of the protocol (cycle length). Protocols
- * are scheduled independently of each other.
- *
- * @config
- */
- private static final String PAR_PROTOCOL = "protocol";
-
- /**
- * If set, it means that the initial execution of the given protocol is
- * scheduled for a different random time for all nodes. The random time is a
- * sample between the current time (inclusive) and the cycle length
- * (exclusive), the latter being specified by the step parameter (see
- * {@link Scheduler}) of the assigned protocol.
- *
- * @see #execute
- * @config
- */
- private static final String PAR_RNDSTART = "randstart";
-
- /**
- * Contains the scheduler objects for all {@link CDProtocol}s defined in the
- * configuration. The length of the array is the number of protocols
- * defined, but those entries that belong to protocols that are not
- * {@link CDProtocol}s are null.
- */
- public static final Scheduler[] sch;
-
- private final NextCycleEvent[] nce;
-
- private final int[] pid;
-
- private final boolean randstart;
-
- // =============================== initialization ======================
- // =====================================================================
-
- /**
- * Loads protocol schedulers for all protocols.
- */
- static {
-
- String[] names = Configuration.getNames(Node.PAR_PROT);
- sch = new Scheduler[names.length];
- for (int i = 0; i < names.length; ++i) {
- if (Network.prototype.getProtocol(i) instanceof CDProtocol)
- // with no default values for step to avoid
- // "overscheduling" due to lack of step option.
- sch[i] = new Scheduler(names[i], false);
- }
- }
-
- // --------------------------------------------------------------------
-
- /**
- * Initialization based on configuration parameters.
- */
- public CDScheduler(String n) {
- String[] prots = Configuration.getString(n + "." + PAR_PROTOCOL).split("\\s");
- pid = new int[prots.length];
- nce = new NextCycleEvent[prots.length];
- for (int i = 0; i < prots.length; ++i) {
- pid[i] = Configuration.lookupPid(prots[i]);
- if (!(Network.prototype.getProtocol(pid[i]) instanceof CDProtocol)) {
- throw new IllegalParameterException(n + "." + PAR_PROTOCOL,
- "Only CDProtocols are accepted here");
- }
- nce[i] = (NextCycleEvent) Configuration.getInstance(n + "."
- + PAR_NEXTC, new NextCycleEvent(null));
- }
- randstart = Configuration.contains(n + "." + PAR_RNDSTART);
- }
-
- // ========================== methods ==================================
- // =====================================================================
-
- /**
- * Schedules the protocol at all nodes for the first execution adding it to
- * the priority queue of the event driven simulation. The time of the first
- * execution is determined by {@link #firstDelay}. The implementation calls
- * {@link #initialize} for all nodes.
- *
- * @see #initialize
- */
- public boolean execute() {
-
- for (int i = 0; i < Network.size(); ++i) {
- initialize(Network.get(i));
- }
-
- return false;
- }
-
- // --------------------------------------------------------------------
-
- /**
- * Schedules the protocol at given node for the first execution adding it to
- * the priority queue of the event driven simulation. The time of the first
- * execution is determined by a reference point in time and
- * {@link #firstDelay}, which defines the delay from the reference point.
- * The reference point is the maximum of the current time, and the value of
- * parameter {@value peersim.core.Scheduler#PAR_FROM} of the protocol being
- * scheduled. If the calculated time of the first execution is not valid
- * according to the schedule of the protocol then no execution is scheduled
- * for that protocol.
- * <p>
- * A final note: for performance reasons, the recommended practice is not to
- * use parameter {@value peersim.core.Scheduler#PAR_FROM} in protocols, but
- * to schedule {@link CDScheduler} itself for the desired time, whenever
- * possible (e.g., it is not possible if {@link CDScheduler} is used as a
- * {@link NodeInitializer}).
- */
- public void initialize(Node n) {
- /*
- * XXX If "from" is not the current time and this is used as a control
- * (not node initializer) then we dump _lots_ of events in the queue
- * that are just stored there until "from" comes. This reduces
- * performance, and should be fixed. When fixed, the final comment can
- * be removed from the docs.
- */
-
- final long time = CommonState.getTime();
- for (int i = 0; i < pid.length; ++i) {
- Object nceclone = null;
- try {
- nceclone = nce[i].clone();
- } catch (CloneNotSupportedException e) {
- } // cannot possibly happen
-
- final long delay = firstDelay(sch[pid[i]].step);
- final long nexttime = Math.max(time, sch[pid[i]].from) + delay;
- if (nexttime < sch[pid[i]].until)
- EDSimulator.add(nexttime - time, nceclone, n, pid[i]);
- }
- }
-
- // --------------------------------------------------------------------
-
- /**
- * Returns the time (through giving the delay from the current time) when
- * this even is first executed. If {@value #PAR_RNDSTART} is not set, it
- * returns zero, otherwise a random value between 0, inclusive, and
- * cyclelength, exclusive.
- *
- * @param cyclelength
- * The cycle length of the cycle based protocol for which this
- * method is called
- */
- protected long firstDelay(long cyclelength) {
-
- if (randstart)
- return CommonState.r.nextLong(cyclelength);
- else
- return 0;
- }
-}
