A UUIDFetcher for techcable's uuid service with caching

UUIDFetcher.java

import java.lang.ref.SoftReference;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.IOException;
import java.net.URL;
import java.util.HashMap;
import java.util.Map;
import java.util.UUID;
 
/**
 * Utilities to lookup player names and uuids from techcable's uuid service
 * This caches results so you won't have issues with the rate limit
 * 
 * <p>
 * <b>DONT Rely on Bukkit.getOfflinePlayer()</b>
 * It doesn't cache and is a workaround solution
 * 
 * evilmidgets fetchers are a fair solution, but they don't cache so you can run into ratelimits
 * 
 * @author Techcable
 */
public class UUIDFetcher {
    private UUIDFetcher() {}
 
    private static Cache<String, PlayerProfile> nameCache = new Cache<String, PlayerProfile>();
    private static Cache<UUID, PlayerProfile> idCache = new Cache<UUID, PlayerProfile>();
 
    /**
     * Lookup a profile with the given name
     * 
     * Returns null in the event of failure
     * 
     * @param name look for a profile with this name
     * @return a profile with the given name, or null if failed
     */
    public static PlayerProfile lookup(String name) {
        if (name == null) return null;
        if (nameCache.contains(name)) return nameCache.get(name);
        String rawUuid = get("http://uuid.techcable.net/api/uuid/" + name);
        if (name == null) return null;
        if (rawUuid == "unknown" || rawUuid == "error") return null;
        UUID id = UUID.fromString(rawUuid);
        PlayerProfile player = new PlayerProfile(id, name);
        nameCache.put(name, player);
        return player;
    }
    
    /**
     * Lookup a profile with the given uuid
     * 
     * Returns null in the event of failure
     * 
     * @param id look for a profile with this uuid
     * @return a profile with the given id, or null if failed
     */
    public static PlayerProfile lookup(UUID id) {
        if (id == null) return null;
        if (idCache.contains(id)) return idCache.get(id);
        String name = get("http://uuid.techcable.net/api/name/" + id.toString());
        if (name == null) return null;
        if (name == "\"error\"") return null;
        PlayerProfile player = new PlayerProfile(id, name);
        idCache.put(id, player);
        return player;
    }
 
    /**
     * Represnents a player
     * Contains their uuid and username
     * 
     * @author Techcable
     */
    public static class PlayerProfile {
        
        public PlayerProfile(UUID id, String name) {
            this.id = id;
            this.name = name;
        }
        
        private final UUID id;
        private final String name;
        
        /**
         * Get this player's uuid
         * 
         * @return this players uuid
         */
        public UUID getId() {
            return id;
        }
        
        /**
         * Get this player's name
         *
         * @return this player's name
         */
        public String getName() {
            return name;
        }
    }
    
    //Utilities
    
    public static String get(String rawUrl) {
        BufferedReader reader = null;
        try {
            URL url = new URL(rawUrl);
            
            reader = new BufferedReader(new InputStreamReader(url.openStream()));
            StringBuffer result = new StringBuffer();
            String line;
            while ((line = reader.readLine()) != null) result.append(line);
            return result.toString();
        } catch (IOException ex) {
            ex.printStackTrace();
            return null;
        } finally {
            try {
                if (reader != null) reader.close();
            } catch (IOException ex) {
                ex.printStackTrace();
                return null;
            }
        }
    }
    
    private static class Cache<K, V> {
 
        private long expireTime = 1000 * 60 * 5; //default 5 min
        private Map<K, CachedEntry<V>> map = new HashMap<>();
 
        public boolean contains(K key) {
            return map.containsKey(key) && get(key) != null;
        }
 
        public V get(K key) {
            CachedEntry<V> entry = map.get(key);
            if (entry == null) return null;
            if (entry.isExpired()) {
                map.remove(key);
                return null;
            } else {
                return entry.getValue();
            }
        }
    
        public void put(K key, V value) {
            map.put(key, new CachedEntry<V>(value, expireTime));
        }
 
        private static class CachedEntry<V> {
 
            public CachedEntry(V value, long expireTime) {
                this.value = new SoftReference<V>(value);
                this.expires = expireTime + System.currentTimeMillis();
            }
 
            private final SoftReference<V> value; //Caching is low memory priortiy
            private final long expires;
 
            public V getValue() {
                if (isExpired()) {
                    return null;
                }
                return value.get();
            }
 
            public boolean isExpired() {
                if (value.get() == null) return true;
                return expires != -1 && expires > System.currentTimeMillis();
            }
        }
    }
}