adds proxy sessions, fixing auto login from bungee messages issues (#2285)

src/main/java/fr/xephi/authme/data/ProxySessionManager.java

@@ -0,0 +1,48 @@
+package fr.xephi.authme.data;
+
+import fr.xephi.authme.initialization.HasCleanup;
+import fr.xephi.authme.util.expiring.ExpiringSet;
+
+import javax.inject.Inject;
+import java.util.concurrent.TimeUnit;
+
+public class ProxySessionManager implements HasCleanup {
+
+    private final ExpiringSet<String> activeProxySessions;
+
+    @Inject
+    public ProxySessionManager() {
+        long countTimeout = 5;
+        activeProxySessions = new ExpiringSet<>(countTimeout, TimeUnit.SECONDS);
+    }
+
+    /**
+     * Saves the player in the set
+     * @param name the player's name
+     */
+    private void setActiveSession(String name) {
+        activeProxySessions.add(name.toLowerCase());
+    }
+
+    /**
+     * Process a proxy session message from AuthMeBungee
+     * @param name the player to process
+     */
+    public void processProxySessionMessage(String name) {
+        setActiveSession(name);
+    }
+
+    /**
+     * Returns if the player should be logged in or not
+     * @param name the name of the player to check
+     * @return true if player has to be logged in, false otherwise
+     */
+    public boolean shouldResumeSession(String name) {
+        return activeProxySessions.contains(name);
+    }
+
+    @Override
+    public void performCleanup() {
+        activeProxySessions.removeExpiredEntries();
+    }
+}