Apply minor changes to PurgeService

- Remove various imports / unused fields
- Make CacheDataSource call source for purging on DB
- Minor: SQLite - place creation of PreparedStatement outside of loop
- Make specific purge actions called from task package-private (clearer from the outside which methods can be called from the outside)

src/main/java/fr/xephi/authme/datasource/CacheDataSource.java

@@ -145,6 +145,7 @@ public class CacheDataSource implements DataSource {
 
     @Override
     public void purgeRecords(Set<String> toPurge) {
+        source.purgeRecords(toPurge);
         for (String name : toPurge) {
             cachedAuths.invalidate(name);
         }

src/main/java/fr/xephi/authme/datasource/FlatFile.java

@@ -8,7 +8,6 @@ import fr.xephi.authme.cache.auth.PlayerCache;
 import fr.xephi.authme.security.crypts.HashedPassword;
 import fr.xephi.authme.settings.Settings;
 
-import javax.swing.*;
 import java.io.BufferedReader;
 import java.io.BufferedWriter;
 import java.io.Closeable;

src/main/java/fr/xephi/authme/datasource/SQLite.java

@@ -1,5 +1,14 @@
 package fr.xephi.authme.datasource;
 
+import com.google.common.annotations.VisibleForTesting;
+import fr.xephi.authme.ConsoleLogger;
+import fr.xephi.authme.cache.auth.PlayerAuth;
+import fr.xephi.authme.security.crypts.HashedPassword;
+import fr.xephi.authme.settings.NewSetting;
+import fr.xephi.authme.settings.Settings;
+import fr.xephi.authme.settings.properties.DatabaseSettings;
+import fr.xephi.authme.util.StringUtils;
+
 import java.sql.Connection;
 import java.sql.DriverManager;
 import java.sql.PreparedStatement;
@@ -11,16 +20,6 @@ import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
 
-import com.google.common.annotations.VisibleForTesting;
-
-import fr.xephi.authme.ConsoleLogger;
-import fr.xephi.authme.cache.auth.PlayerAuth;
-import fr.xephi.authme.security.crypts.HashedPassword;
-import fr.xephi.authme.settings.NewSetting;
-import fr.xephi.authme.settings.Settings;
-import fr.xephi.authme.settings.properties.DatabaseSettings;
-import fr.xephi.authme.util.StringUtils;
-
 /**
  */
 public class SQLite implements DataSource {
@@ -314,13 +313,13 @@ public class SQLite implements DataSource {
     @Override
     public void purgeRecords(Set<String> toPurge) {
         String delete = "DELETE FROM " + tableName + " WHERE " + col.NAME + "=?;";
-        for (String name : toPurge) {
-            try (PreparedStatement deletePst = con.prepareStatement(delete)) {
+        try (PreparedStatement deletePst = con.prepareStatement(delete)) {
+            for (String name : toPurge) {
                 deletePst.setString(1, name);
                 deletePst.executeUpdate();
-            } catch (SQLException ex) {
-                logSqlException(ex);
             }
+        } catch (SQLException ex) {
+            logSqlException(ex);
         }
     }