#472 Store recovery codes in memory instead of in data source

src/main/java/fr/xephi/authme/service/RecoveryCodeManager.java

@@ -0,0 +1,73 @@
+package fr.xephi.authme.service;
+
+import fr.xephi.authme.initialization.SettingsDependent;
+import fr.xephi.authme.security.RandomString;
+import fr.xephi.authme.settings.Settings;
+import fr.xephi.authme.settings.properties.SecuritySettings;
+
+import javax.inject.Inject;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+import static fr.xephi.authme.settings.properties.SecuritySettings.RECOVERY_CODE_HOURS_VALID;
+import static fr.xephi.authme.util.Utils.MILLIS_PER_HOUR;
+
+/**
+ * Manager for recovery codes.
+ */
+public class RecoveryCodeManager implements SettingsDependent {
+
+    private Map<String, TimedEntry> recoveryCodes = new ConcurrentHashMap<>();
+
+    private int recoveryCodeLength;
+    private long recoveryCodeExpirationMillis;
+
+    @Inject
+    RecoveryCodeManager(Settings settings) {
+        reload(settings);
+    }
+
+    public boolean isRecoveryCodeNeeded() {
+        return recoveryCodeExpirationMillis > 0;
+    }
+
+    public String generateCode(String player) {
+        String code = RandomString.generateHex(recoveryCodeLength);
+        recoveryCodes.put(player, new TimedEntry(code, System.currentTimeMillis() + recoveryCodeExpirationMillis));
+        return code;
+    }
+
+    public boolean isCodeValid(String player, String code) {
+        TimedEntry entry = recoveryCodes.get(player);
+        if (entry != null) {
+            return code != null && code.equals(entry.getCode());
+        }
+        return false;
+    }
+
+    public void removeCode(String player) {
+        recoveryCodes.remove(player);
+    }
+
+    @Override
+    public void reload(Settings settings) {
+        recoveryCodeLength = settings.getProperty(SecuritySettings.RECOVERY_CODE_LENGTH);
+        recoveryCodeExpirationMillis = settings.getProperty(RECOVERY_CODE_HOURS_VALID) * MILLIS_PER_HOUR;
+    }
+
+    private static final class TimedEntry {
+
+        private final String code;
+        private final long expiration;
+
+        TimedEntry(String code, long expiration) {
+            this.code = code;
+            this.expiration = expiration;
+        }
+
+        public String getCode() {
+            return System.currentTimeMillis() < expiration ? code : null;
+        }
+    }
+
+}