org/objectweb/proactive/core/body/migration/MixedLocationServer.java

/* 
 * ################################################################
 * 
 * ProActive: The Java(TM) library for Parallel, Distributed, 
 *            Concurrent computing with Security and Mobility
 * 
 * Copyright (C) 1997-2007 INRIA/University of Nice-Sophia Antipolis
 * Contact: proactive@objectweb.org
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or any later version.
 *  
 * This library 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 library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307
 * USA
 *  
 *  Initial developer(s):               The ProActive Team
 *                        http://www.inria.fr/oasis/ProActive/contacts.html
 *  Contributor(s): 
 * 
 * ################################################################
 */ 
package org.objectweb.proactive.core.body.migration;

import java.io.IOException;
import java.net.UnknownHostException;
import java.util.Hashtable;

import org.apache.log4j.Logger;
import org.objectweb.proactive.ProActive;
import org.objectweb.proactive.Service;
import org.objectweb.proactive.core.UniqueID;
import org.objectweb.proactive.core.body.UniversalBody;
import org.objectweb.proactive.core.body.request.Request;
import org.objectweb.proactive.core.config.ProActiveConfiguration;
import org.objectweb.proactive.core.node.NodeFactory;
import org.objectweb.proactive.core.util.UrlBuilder;
import org.objectweb.proactive.core.util.log.Loggers;
import org.objectweb.proactive.core.util.log.ProActiveLogger;
import org.objectweb.proactive.ext.locationserver.LocationServer;
import org.objectweb.proactive.ext.security.exceptions.RenegotiateSessionException;

public class MixedLocationServer implements org.objectweb.proactive.RunActive,
                LocationServer {
        static Logger logger = ProActiveLogger.getLogger(Loggers.MIGRATION);

        public static final int DELAY_SAME_REPLY = 1000;

        private LocationMap table;

        private Hashtable requestTable;

        private String url;

        public MixedLocationServer() {}

        public MixedLocationServer(String url) {
                this.url = normalizeURL(url);
                this.table = new LocationMap();
                this.requestTable = new Hashtable();
        }

        public void updateLocation(UniqueID i, UniversalBody s) {
                updateLocation(i, s, LocationMap.CONSTANT_VERSION);
        }

        public void updateLocation(UniqueID i, UniversalBody s, int version) {
                table.updateBody(i, s, version);
        }

        public UniversalBody searchObject(UniqueID id) {
                //System.out.print("Searching for "+ id);
                UniversalBody u = (UniversalBody) table.getBody(id);
                return u;
        }

        public void runActivity(org.objectweb.proactive.Body body) {

                this.register();
                Service service = new Service(body);

                while (body.isActive()) {
                        while (service.hasRequestToServe("updateLocation")) {
                                service.serveOldest("updateLocation");
                        }
                        Request oldest = service.blockingRemoveOldest();

                        if (oldest != null) {
                                synchronized (this.requestTable) {
                                        if (oldest.getMethodName().equals("searchObject")) {
                                                // we have to verify if we have received a request of
                                                // the
                                                // same sender for the same ID
                                                UniqueID id = (UniqueID) oldest.getParameter(0);
                                                String requestID = oldest.getSender().getID()
                                                                .toString()
                                                                + id.toString();

                                                LocationRequestInfo oldRequest = (LocationRequestInfo) requestTable
                                                                .get(requestID);

                                                if (oldRequest != null) {
                                                        int oldVersion = oldRequest.getVersion();
                                                        // an old version exists
                                                        // if we don't have the same version ==> serve this
                                                        // request and save it
                                                        int newVersion = table.getVersion(id);
                                                        if (oldVersion != newVersion) {
                                                                service.serve(oldest);
                                                                requestTable.put(requestID,
                                                                                new LocationRequestInfo(newVersion,
                                                                                                System.currentTimeMillis(),
                                                                                                true));

                                                        } else {
                                                                // we still have the same version
                                                                // if the previous call hasn't been served ==>
                                                                // have a look to it's creation time
                                                                // else put the request in the table and in the
                                                                // queue
                                                                if (oldRequest.hasBeenServed()) {
                                                                        requestTable.put(requestID,
                                                                                        new LocationRequestInfo(newVersion,
                                                                                                        System.currentTimeMillis(),
                                                                                                        false));
                                                                        try {
                                                                                body.receiveRequest(oldest);
                                                                        } catch (IOException e) {
                                                                                e.printStackTrace();
                                                                        } catch (RenegotiateSessionException e) {
                                                                                e.printStackTrace();
                                                                        }
                                                                } else {
                                                                        // if the delay is gone, serve the request
                                                                        // else put it in the queue
                                                                        if (oldRequest.getCreationTime()
                                                                                        + DELAY_SAME_REPLY < System
                                                                                        .currentTimeMillis()) {
                                                                                service.serve(oldest);
                                                                                oldRequest.setServed(true);
                                                                        } else {
                                                                                try {
                                                                                        body.receiveRequest(oldest);
                                                                                } catch (IOException e) {
                                                                                        e.printStackTrace();
                                                                                } catch (RenegotiateSessionException e) {
                                                                                        e.printStackTrace();
                                                                                }
                                                                        }
                                                                }

                                                        }
                                                } else {
                                                        // no old request so serve the request and save it
                                                        service.serve(oldest);

                                                        int version = table.getVersion(id);
                                                        requestTable.put(requestID,
                                                                        new LocationRequestInfo(version, System
                                                                                        .currentTimeMillis(), true));
                                                }

                                        } else {
                                                service.serve(oldest);
                                        }
                                }
                        }
                }
        }

        protected String normalizeURL(String url) {
                String tmp = url;

                try {
                        tmp = UrlBuilder.checkUrl(url);
                } catch (UnknownHostException e) {
                        e.printStackTrace();
                }
                return tmp;
        }

        protected void register() {
                try {
                        logger.info("Attempt at binding : " + url);
                        ProActive.register(ProActive.getStubOnThis(), url);
                        logger.info("Location Server bound in registry : " + url);
                } catch (Exception e) {
                        logger.fatal("Cannot bind in registry - aborting " + url);
                        e.printStackTrace();
                        return;
                }
        }

        public static void main(String[] args) {
                ProActiveConfiguration.load();
                String name = ProActiveConfiguration.getLocationServerRmi();

                Object[] arg = new Object[1];
                arg[0] = name;

                MixedLocationServer server = null;

                try {

                        if (args.length == 1) {
                                server = (MixedLocationServer) ProActive.newActive(
                                                MixedLocationServer.class.getName(), arg, NodeFactory
                                                                .getNode(args[0]));
                        } else {
                                server = (MixedLocationServer) ProActive.newActive(
                                                MixedLocationServer.class.getName(), arg);
                        }
                } catch (Exception e) {
                        e.printStackTrace();
                }
        }

        //
        // -- INNER CLASSES -----------------------------------------------
        //

        protected class LocationMap {
                public static final int CONSTANT_VERSION = 0;

                public static final int NO_VERSION_FOUND = -1;

                public static final int MIGRATING_OUT = 2000;

                private Hashtable idToBodyMap;

                public LocationMap() {
                        idToBodyMap = new Hashtable();
                }

                public void updateBody(UniqueID id, UniversalBody body, int version) {
                        synchronized (this.idToBodyMap) {
                                // remove old reference if exists and if is an older version
                                WrappedLocationBody wrappedBody = (WrappedLocationBody) idToBodyMap
                                                .get(id);

                                if (wrappedBody == null) {
                                        // add new reference
                                        idToBodyMap.put(id, new WrappedLocationBody(body, version));
                                } else if (wrappedBody.getVersion() <= version) {
                                        idToBodyMap.remove(id);

                                        // add new reference
                                        idToBodyMap.put(id, new WrappedLocationBody(body, version));
                                }
                        }
                }

                public UniversalBody getBody(UniqueID id) {
                        Object o = null;
                        if (id != null) {
                                synchronized (this.idToBodyMap) {
                                        o = idToBodyMap.get(id);
                                        if (o != null) {
                                                /*
                                                WrappedLocationBody wrappedBody = (WrappedLocationBody) o;
                                                
                                                if (wrappedBody.isMigrating()) {
                                                        try {
                                                                wait(MIGRATING_OUT);
                                                        } catch (InterruptedException e) {
                                                                e.printStackTrace();
                                                        }
                                                }
                                                */
                                                return ((WrappedLocationBody) o).getBody();
                                        }
                                }
                        }

                        return (UniversalBody) o;
                }

                public int getVersion(UniqueID id) {
                        if (id != null) {
                                synchronized (this.idToBodyMap) {
                                        Object o = idToBodyMap.get(id);
                                        if (o != null) {
                                                WrappedLocationBody wrappedBody = (WrappedLocationBody) o;
                                                return wrappedBody.getVersion();
                                        }
                                }
                        }
                        return NO_VERSION_FOUND;

                }
        }

        protected class WrappedLocationBody {
                private int version;

                private UniversalBody wrappedBody;

                private boolean isMigrating;

                public WrappedLocationBody(UniversalBody body, int version) {
                        this.wrappedBody = body;
                        this.version = version;
                        this.isMigrating = false;
                }

                public WrappedLocationBody(UniversalBody body, int version,
                                boolean isMigrating) {
                        this.wrappedBody = body;
                        this.version = version;
                        this.isMigrating = isMigrating;
                }

                public int getVersion() {
                        return this.version;
                }

                public UniversalBody getBody() {
                        return this.wrappedBody;
                }

                public boolean isMigrating() {
                        return this.isMigrating;
                }

        }

        protected class LocationRequestInfo {
                private int version;

                private long creationTime;

                private boolean served;

                public LocationRequestInfo(int version, long creationTime,
                                boolean served) {
                        this.version = version;
                        this.creationTime = creationTime;
                        this.served = served;
                }

                public boolean hasBeenServed() {
                        return this.served;
                }

                public int getVersion() {
                        return this.version;
                }

                public long getCreationTime() {
                        return this.creationTime;
                }

                public void setServed(boolean served) {
                        this.served = served;
                }
        }

}

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