add lock to modify sql storage

Author: HSGamer

storage/simple/src/main/java/me/hsgamer/topper/storage/simple/supplier/SqlStorageSupplier.java

@@ -11,15 +11,22 @@
 import java.sql.Connection;
 import java.sql.SQLException;
 import java.util.*;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReentrantLock;
 import java.util.stream.Collectors;
 
 public abstract class SqlStorageSupplier implements DataStorageSupplier {
     protected final Logger logger = LoggerProvider.getLogger(getClass());
+    private final Lock lock = new ReentrantLock();
 
     protected abstract Connection getConnection() throws SQLException;
 
     protected abstract void flushConnection(Connection connection);
 
+    protected boolean shouldLockWhenModify() {
+        return false;
+    }
+
     protected abstract List<String> toSaveStatement(String name, String[] keyColumns, String[] valueColumns);
 
     protected abstract List<Object[]> toSaveValues(Object[] keys, Object[] values);
@@ -86,6 +93,9 @@ public Optional<V> load(K key) {
 
             @Override
             public Optional<Modifier<K, V>> modify() {
+                if (shouldLockWhenModify()) {
+                    lock.lock();
+                }
                 try {
                     Connection connection = getConnection();
                     Modifier<K, V> modifier = new Modifier<K, V>() {
@@ -144,6 +154,9 @@ public void commit() {
                                 logger.log(LogLevel.ERROR, "Failed to commit", e);
                             } finally {
                                 flushConnection(connection);
+                                if (shouldLockWhenModify()) {
+                                    lock.unlock();
+                                }
                             }
                         }
 
@@ -155,6 +168,9 @@ public void rollback() {
                                 logger.log(LogLevel.ERROR, "Failed to rollback", e);
                             } finally {
                                 flushConnection(connection);
+                                if (shouldLockWhenModify()) {
+                                    lock.unlock();
+                                }
                             }
                         }
                     };

storage/simple/src/main/java/me/hsgamer/topper/storage/simple/supplier/SqliteStorageSupplier.java

@@ -45,6 +45,11 @@ protected void flushConnection(Connection connection) {
         // EMPTY
     }
 
+    @Override
+    protected boolean shouldLockWhenModify() {
+        return true;
+    }
+
     @Override
     protected List<String> toSaveStatement(String name, String[] keyColumns, String[] valueColumns) {
         StringBuilder insertStatement = new StringBuilder("INSERT OR IGNORE INTO `")