Implement close on LimboStatement and JDBC4Statement independently

bindings/java/src/main/java/org/github/tursodatabase/core/LimboResultSet.java

@@ -114,7 +114,6 @@ public class LimboResultSet {
   }
 
   public void close() throws SQLException {
-    this.statement.close();
     this.open = false;
   }
 

bindings/java/src/main/java/org/github/tursodatabase/core/LimboStatement.java

@@ -21,6 +21,8 @@ public class LimboStatement {
   private final long statementPointer;
   private final LimboResultSet resultSet;
 
+  private boolean closed;
+
   // TODO: what if the statement we ran was DDL, update queries and etc. Should we still create a
   // resultSet?
   public LimboStatement(String sql, long statementPointer) {
@@ -71,12 +73,26 @@ public class LimboStatement {
    * Closes the current statement and releases any resources associated with it. This method calls
    * the native `_close` method to perform the actual closing operation.
    */
-  public void close() {
+  public void close() throws SQLException {
+    if (closed) {
+      return;
+    }
+    this.resultSet.close();
     _close(statementPointer);
+    closed = true;
   }
 
   private native void _close(long statementPointer);
 
+  /**
+   * Checks if the statement is closed.
+   *
+   * @return true if the statement is closed, false otherwise.
+   */
+  public boolean isClosed() {
+    return closed;
+  }
+
   @Override
   public String toString() {
     return "LimboStatement{"

bindings/java/src/main/java/org/github/tursodatabase/jdbc4/JDBC4Statement.java

@@ -19,6 +19,8 @@ public class JDBC4Statement implements Statement {
   private final LimboConnection connection;
   @Nullable private LimboStatement statement = null;
 
+  // Because JDBC4Statement has different life cycle in compared to LimboStatement, let's use this
+  // field to manage JDBC4Statement lifecycle
   private boolean closed;
   private boolean closeOnCompletion;
 
@@ -73,8 +75,14 @@ public class JDBC4Statement implements Statement {
 
   @Override
   public void close() throws SQLException {
-    clearGeneratedKeys();
-    internalClose();
+    if (closed) {
+      return;
+    }
+
+    if (this.statement != null) {
+      this.statement.close();
+    }
+
     closed = true;
   }
 
@@ -148,8 +156,7 @@ public class JDBC4Statement implements Statement {
    */
   @Override
   public boolean execute(String sql) throws SQLException {
-    internalClose();
-
+    ensureOpen();
     return this.withConnectionTimeout(
         () -> {
           try {
@@ -296,8 +303,7 @@ public class JDBC4Statement implements Statement {
 
   @Override
   public boolean isClosed() throws SQLException {
-    // TODO
-    return false;
+    return this.closed;
   }
 
   @Override
@@ -344,14 +350,6 @@ public class JDBC4Statement implements Statement {
     return false;
   }
 
-  protected void internalClose() throws SQLException {
-    // TODO
-  }
-
-  protected void clearGeneratedKeys() throws SQLException {
-    // TODO
-  }
-
   protected void updateGeneratedKeys() throws SQLException {
     // TODO
   }
@@ -376,4 +374,10 @@ public class JDBC4Statement implements Statement {
   protected interface SQLCallable<T> {
     T call() throws SQLException;
   }
+
+  private void ensureOpen() throws SQLException {
+    if (closed) {
+      throw new SQLException("Statement is closed");
+    }
+  }
 }

bindings/java/src/test/java/org/github/tursodatabase/core/LimboStatementTest.java

@@ -0,0 +1,31 @@
+package org.github.tursodatabase.core;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import java.util.Properties;
+import org.github.tursodatabase.TestUtils;
+import org.github.tursodatabase.jdbc4.JDBC4Connection;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+class LimboStatementTest {
+
+  private JDBC4Connection connection;
+
+  @BeforeEach
+  void setUp() throws Exception {
+    String filePath = TestUtils.createTempFile();
+    String url = "jdbc:sqlite:" + filePath;
+    connection = new JDBC4Connection(url, filePath, new Properties());
+  }
+
+  @Test
+  void closing_statement_closes_related_resources() throws Exception {
+    LimboStatement stmt = connection.prepare("SELECT 1");
+    stmt.execute();
+
+    stmt.close();
+    assertTrue(stmt.isClosed());
+    assertFalse(stmt.getResultSet().isOpen());
+  }
+}

bindings/java/src/test/java/org/github/tursodatabase/jdbc4/JDBC4StatementTest.java

@@ -3,6 +3,7 @@ package org.github.tursodatabase.jdbc4;
 import static org.junit.jupiter.api.Assertions.*;
 
 import java.sql.ResultSet;
+import java.sql.SQLException;
 import java.sql.Statement;
 import java.util.Properties;
 import org.github.tursodatabase.TestUtils;
@@ -51,4 +52,22 @@ class JDBC4StatementTest {
     stmt.execute("INSERT INTO users VALUES (1, 'limbo');");
     assertTrue(stmt.execute("SELECT * FROM users;"));
   }
+
+  @Test
+  void close_statement_test() throws Exception {
+    stmt.close();
+    assertTrue(stmt.isClosed());
+  }
+
+  @Test
+  void double_close_is_no_op() throws SQLException {
+    stmt.close();
+    assertDoesNotThrow(() -> stmt.close());
+  }
+
+  @Test
+  void operations_on_closed_statement_should_throw_exception() throws Exception {
+    stmt.close();
+    assertThrows(SQLException.class, () -> stmt.execute("SELECT 1"));
+  }
 }