Initial pass on step function

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

@@ -23,7 +23,7 @@ public abstract class LimboConnection implements Connection {
     }
 
     /**
-     * Creates a connection to limbo database.
+     * Creates a connection to limbo database
      *
      * @param url      e.g. "jdbc:sqlite:fileName"
      * @param filePath path to file

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

@@ -4,7 +4,6 @@ package org.github.tursodatabase.core;
 import org.github.tursodatabase.LimboErrorCode;
 import org.github.tursodatabase.annotations.NativeInvocation;
 import org.github.tursodatabase.annotations.VisibleForTesting;
-import org.github.tursodatabase.utils.ByteArrayUtils;
 import org.github.tursodatabase.utils.LimboExceptionUtils;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;

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

@@ -1,9 +1,13 @@
 package org.github.tursodatabase.core;
 
+import org.github.tursodatabase.annotations.NativeInvocation;
 import org.github.tursodatabase.annotations.Nullable;
 import org.github.tursodatabase.jdbc4.JDBC4ResultSet;
+import org.github.tursodatabase.utils.LimboExceptionUtils;
 
 import java.sql.SQLException;
+import java.util.ArrayList;
+import java.util.List;
 
 public abstract class LimboStatement {
 
@@ -30,20 +34,33 @@ public abstract class LimboStatement {
         // TODO
     }
 
-    /**
-     * Calls sqlite3_step() and sets up results.
-     *
-     * @return true if the ResultSet has at least one row; false otherwise;
-     * @throws SQLException If the given SQL statement is nul or no database is open;
-     */
-    protected boolean exec(long stmtPointer) throws SQLException {
-        if (sql == null) throw new SQLException("SQL must not be null");
+    // TODO: enhance
+    protected List<Object[]> execute(long stmtPointer) throws SQLException {
+        List<Object[]> result = new ArrayList<>();
+        while (true) {
+            Object[] stepResult = step(stmtPointer);
+            if (stepResult != null) {
+                for (int i = 0; i < stepResult.length; i++) {
+                    System.out.println("stepResult" + i + ": " + stepResult[i]);
+                }
+            }
+            if (stepResult == null) break;
+            result.add(stepResult);
+        }
 
-        // TODO
-        return true;
+        return result;
     }
 
-    protected void step(long stmtPointer) throws SQLException {
-        // TODO
+    private native Object[] step(long stmtPointer) throws SQLException;
+
+    /**
+     * Throws formatted SQLException with error code and message.
+     *
+     * @param errorCode         Error code.
+     * @param errorMessageBytes Error message.
+     */
+    @NativeInvocation
+    private void throwLimboException(int errorCode, byte[] errorMessageBytes) throws SQLException {
+        LimboExceptionUtils.throwLimboException(errorCode, errorMessageBytes);
     }
 }

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

@@ -1,10 +1,12 @@
 package org.github.tursodatabase.jdbc4;
 
 import org.github.tursodatabase.annotations.SkipNullableCheck;
-import org.github.tursodatabase.core.LimboStatement;
 import org.github.tursodatabase.core.LimboConnection;
+import org.github.tursodatabase.core.LimboStatement;
 
 import java.sql.*;
+import java.util.ArrayList;
+import java.util.List;
 import java.util.concurrent.locks.ReentrantLock;
 
 /**
@@ -128,11 +130,10 @@ public class JDBC4Statement extends LimboStatement implements Statement {
                     try {
                         connectionLock.lock();
                         final long stmtPointer = connection.prepare(sql);
-                        boolean result = exec(stmtPointer);
+                        List<Object[]> result = execute(stmtPointer);
                         updateGeneratedKeys();
-                        // TODO: updateCount = connection.changes();
                         exhaustedResults = false;
-                        return result;
+                        return !result.isEmpty();
                     } finally {
                         connectionLock.unlock();
                     }

bindings/java/src/test/java/org/github/tursodatabase/jdbc4/JDBC4ConnectionTest.java

@@ -64,7 +64,9 @@ class JDBC4ConnectionTest {
     @Test
     void exec_simple_create_table() throws Exception {
         Statement stmt = createDefaultStatement();
-        stmt.execute("CREATE TABLE users (id PRIMARY KEY INT, username TEXT)");
+        stmt.execute("CREATE TABLE users (id INT PRIMARY KEY, username TEXT);");
+        stmt.execute("INSERT INTO users VALUES (1, 'seonwoo');");
+        stmt.execute("SELECT * FROM users;");
     }
 
     private Statement createDefaultStatement() throws SQLException {