GremlinSessions.java

package com.tinkerpop.rexster.gremlin;

import com.tinkerpop.rexster.server.RexsterApplication;

import java.util.Collection;
import java.util.Iterator;
import java.util.concurrent.ConcurrentHashMap;

/**
 * Keeps track of currently running gremlin sessions. Each one is associated
 * with a web client and a particular graph hosted within Rexster.
 * <p/>
 * Credit to Neo Technology (http://neotechnology.com/) for most of the code related to the
 * Gremlin in Rexster.  Specifically, this code was borrowed from
 * https://github.com/neo4j/webadmin and re-purposed for Rexster's needs.
 * <p/>
 * Original author Jacob Hansson <jacob@voltvoodoo.com>
 */
public class GremlinSessions {

    protected static ConcurrentHashMap<String, GremlinSession> sessions = new ConcurrentHashMap<String, GremlinSession>();

    /**
     * Gets a GremlinSession for a given session identifier and graph name,
     * creating a GremlinSession if one does not exist.
     */
    public static GremlinSession getSession(String sessionId, String graphName, RexsterApplication ra) {
        ensureSessionExists(sessionId, graphName, ra);
        return sessions.get(sessionId + graphName);
    }

    public static GremlinSession findSessionByKey(String sessionKey) {
        return sessions.get(sessionKey);
    }

    /**
     * Destroy a session
     *
     * @param sessionId The unique identifier for the session.
     * @param graphName The name of the graph the Gremlin session is connected to.
     */
    public static void destroySession(String sessionId, String graphName) {
        destroySession(sessionId + graphName);
    }

    /**
     * Destroy a session using the session key.
     *
     * @param sessionKey The session identifier concatenated with the graph name.
     */
    public static void destroySession(String sessionKey) {
        sessions.get(sessionKey).die();
        sessions.remove(sessionKey);
    }

    public static void destroyAllSessions() {
        Iterator<String> keys = sessions.keySet().iterator();
        while (keys.hasNext()) {
            destroySession(keys.next());
        }
    }

    public static boolean hasSession(String sessionId, String graphName) {
        return hasSessionKey(sessionId + graphName);
    }

    public static boolean hasSessionKey(String sessionKey) {
        return sessions.containsKey(sessionKey);
    }

    public static Collection<String> getSessionKeys() {
        return sessions.keySet();
    }

    protected static void ensureSessionExists(String sessionId, String graphName, RexsterApplication ra) {
        String key = sessionId + graphName;
        if (!sessions.containsKey(key)) {
            sessions.put(key, new GremlinSession(graphName, ra));
        }
    }

}