source: src/main/java/geniusweb/runserver/RunningNego.java

package geniusweb.runserver;

import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;
import java.net.URISyntaxException;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.logging.Level;

import geniusweb.events.ProtocolEvent;
import geniusweb.protocol.CurrentNegoState;
import geniusweb.protocol.NegoProtocol;
import geniusweb.protocol.NegoSettings;
import geniusweb.protocol.NegoState;
import tudelft.utilities.logging.Reporter;
import tudelft.utilities.repository.RepoElement;

/**
 * Contains a currently running {@link NegoProtocol}. Listens to protocol
 * events. Kept so that we can keep track of the amount of running sessions and
 * show progress states.
 */
public class RunningNego implements RepoElement<String> {
        private static final String LOGDIRNAME = "log";
        private static final Path logdir = getLogDir();
        private static long negoNr = System.currentTimeMillis(); // generate unique IDs.

        private final String sessionid;
        private final transient Reporter log;
        private final transient NegoProtocol protocol;
        private final transient RunningNegotiationsRepo repo;

        /**
         * Create new session wth unique ID. You should call {@link #start()} to
         * actually start this.
         * 
         * @param settings the settings to use for this session
         * @param repo     the {@link RunningNegotiationsRepo} to use (mainly for
         *                 testing)
         * @param logger   the {@link Reporter} to be used. Usually "Protocol" or
         *                 "runserver". The logger is used both for logging protocol
         *                 events and for logging events from this RunningNego
         */
        public RunningNego(NegoSettings settings, RunningNegotiationsRepo repo,
                        Reporter logger) {
                this.log = logger;
                this.protocol = settings.getProtocol(logger);
                this.sessionid = "" + protocol.getRef().getURI() + (negoNr++);
                this.repo = repo;
        }

        public void start() {
                log.log(Level.INFO, "new negotiation session. logging to " + logdir);
                repo.put(this);
                protocol.addListener(evt -> handle(evt));
                protocol.start(new PartyConnectionFactory(log));
        }

        private void handle(ProtocolEvent evt) {
                if (evt instanceof CurrentNegoState) {
                        NegoState state = ((CurrentNegoState) evt).getState();
                        writeLogFile(state);
                        if (state.isFinal(System.currentTimeMillis())) {
                                repo.remove(sessionid);
                        }
                }
        }

        /**
         * Write the (final) state to the log file.
         * 
         * @param sessionState
         * @throws IOException
         */
        protected void writeLogFile(NegoState sessionState) {
                try {
                        PrintWriter out = new PrintWriter(
                                        logdir.resolve(sessionid + ".json").toFile());
                        out.print(Jackson.instance().writeValueAsString(sessionState));
                        out.close();
                } catch (Throwable e) { // also catch outOfMem etc.
                        log.log(Level.SEVERE, "Failed to write log file for " + sessionid,
                                        e);
                }
        }

        /**
         * Search from location of this class upwards till we find a directory
         * called "domainsrepo".
         * 
         * @return the root dir of the repo. This is the 'database' where all known
         *         profiles are stored. If not found , returns log dir in
         *         workingdirectory
         * @throws URISyntaxException
         */
        protected static Path getLogDir() {
                // If you run this normal from tomcat we are somewhere inside
                // projectroot/WEB_INF/classes/....
                // Search back upwards to projectroot.
                Path dir;
                try {
                        dir = Paths.get(RunningNego.class.getProtectionDomain()
                                        .getCodeSource().getLocation().toURI()).getParent();
                } catch (URISyntaxException e) {
                        throw new RuntimeException("Problem with path URI", e);
                }
                System.out.println("searching from " + dir);
                while (dir.getNameCount() > 1) {
                        Path repo = dir.resolve(LOGDIRNAME);
                        if (repo.toFile().exists())
                                return repo;
                        System.out.println(
                                        "Directory did not contain " + LOGDIRNAME + ":" + dir);
                        dir = dir.getParent();
                }

                // fallback to working dir
                File file = new File(LOGDIRNAME);
                if (!file.exists()) {
                        file.mkdir();
                }
                return file.toPath();
        }

        public NegoProtocol getProtocol() {
                return protocol;
        }

        @Override
        public String getID() {
                return sessionid;
        }

        @Override
        public int hashCode() {
                final int prime = 31;
                int result = 1;
                result = prime * result
                                + ((protocol == null) ? 0 : protocol.hashCode());
                result = prime * result
                                + ((sessionid == null) ? 0 : sessionid.hashCode());
                return result;
        }

        @Override
        public boolean equals(Object obj) {
                if (this == obj)
                        return true;
                if (obj == null)
                        return false;
                if (getClass() != obj.getClass())
                        return false;
                RunningNego other = (RunningNego) obj;
                if (protocol == null) {
                        if (other.protocol != null)
                                return false;
                } else if (!protocol.equals(other.protocol))
                        return false;
                if (sessionid == null) {
                        if (other.sessionid != null)
                                return false;
                } else if (!sessionid.equals(other.sessionid))
                        return false;
                return true;
        }

}