Comprehensive comparison for Database technology in Software Development applications

import org.apache.ignite.Ignite;
import org.apache.ignite.IgniteCache;
import org.apache.ignite.Ignition;
import org.apache.ignite.cache.CacheMode;
import org.apache.ignite.cache.query.SqlFieldsQuery;
import org.apache.ignite.configuration.CacheConfiguration;
import org.apache.ignite.configuration.IgniteConfiguration;
import org.apache.ignite.spi.discovery.tcp.TcpDiscoverySpi;
import org.apache.ignite.spi.discovery.tcp.ipfinder.vm.TcpDiscoveryVmIpFinder;
import javax.cache.Cache;
import java.util.Arrays;
import java.util.List;
import java.util.UUID;

/**
 * User Session Management System using Apache Ignite
 * Demonstrates production-ready session caching for distributed web applications
 */
public class UserSessionManager {
    private static final String SESSION_CACHE = "userSessions";
    private Ignite ignite;
    private IgniteCache<String, UserSession> sessionCache;

    public UserSessionManager() {
        this.ignite = initializeIgnite();
        this.sessionCache = getOrCreateSessionCache();
    }

    private Ignite initializeIgnite() {
        IgniteConfiguration cfg = new IgniteConfiguration();
        cfg.setClientMode(false);
        cfg.setPeerClassLoadingEnabled(true);
        
        TcpDiscoverySpi discoverySpi = new TcpDiscoverySpi();
        TcpDiscoveryVmIpFinder ipFinder = new TcpDiscoveryVmIpFinder();
        ipFinder.setAddresses(Arrays.asList("127.0.0.1:47500..47509"));
        discoverySpi.setIpFinder(ipFinder);
        cfg.setDiscoverySpi(discoverySpi);
        
        return Ignition.start(cfg);
    }

    private IgniteCache<String, UserSession> getOrCreateSessionCache() {
        CacheConfiguration<String, UserSession> cacheCfg = new CacheConfiguration<>(SESSION_CACHE);
        cacheCfg.setCacheMode(CacheMode.PARTITIONED);
        cacheCfg.setBackups(1);
        cacheCfg.setIndexedTypes(String.class, UserSession.class);
        return ignite.getOrCreateCache(cacheCfg);
    }

    public String createSession(String userId, String ipAddress) {
        if (userId == null || userId.trim().isEmpty()) {
            throw new IllegalArgumentException("User ID cannot be null or empty");
        }
        
        String sessionId = UUID.randomUUID().toString();
        UserSession session = new UserSession(sessionId, userId, ipAddress, System.currentTimeMillis());
        
        try {
            sessionCache.put(sessionId, session);
            return sessionId;
        } catch (Exception e) {
            throw new RuntimeException("Failed to create session for user: " + userId, e);
        }
    }

    public UserSession getSession(String sessionId) {
        if (sessionId == null) {
            return null;
        }
        
        try {
            return sessionCache.get(sessionId);
        } catch (Exception e) {
            throw new RuntimeException("Failed to retrieve session: " + sessionId, e);
        }
    }

    public boolean validateSession(String sessionId, long maxAgeMillis) {
        UserSession session = getSession(sessionId);
        if (session == null) {
            return false;
        }
        
        long currentTime = System.currentTimeMillis();
        return (currentTime - session.getCreatedAt()) < maxAgeMillis;
    }

    public void invalidateSession(String sessionId) {
        if (sessionId != null) {
            sessionCache.remove(sessionId);
        }
    }

    public List<List<?>> getActiveSessionsByUser(String userId) {
        SqlFieldsQuery query = new SqlFieldsQuery(
            "SELECT sessionId, userId, ipAddress, createdAt FROM UserSession WHERE userId = ?"
        );
        query.setArgs(userId);
        
        try {
            return sessionCache.query(query).getAll();
        } catch (Exception e) {
            throw new RuntimeException("Failed to query sessions for user: " + userId, e);
        }
    }

    public void cleanup(long maxAgeMillis) {
        long threshold = System.currentTimeMillis() - maxAgeMillis;
        SqlFieldsQuery deleteQuery = new SqlFieldsQuery(
            "DELETE FROM UserSession WHERE createdAt < ?"
        );
        deleteQuery.setArgs(threshold);
        sessionCache.query(deleteQuery);
    }

    public void shutdown() {
        if (ignite != null) {
            ignite.close();
        }
    }

    public static class UserSession {
        private String sessionId;
        private String userId;
        private String ipAddress;
        private long createdAt;

        public UserSession(String sessionId, String userId, String ipAddress, long createdAt) {
            this.sessionId = sessionId;
            this.userId = userId;
            this.ipAddress = ipAddress;
            this.createdAt = createdAt;
        }

        public String getSessionId() { return sessionId; }
        public String getUserId() { return userId; }
        public String getIpAddress() { return ipAddress; }
        public long getCreatedAt() { return createdAt; }
    }
}