Add JDBC4ResultSet

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

@@ -0,0 +1,42 @@
+package org.github.tursodatabase.core;
+
+import java.sql.SQLException;
+
+/**
+ * JDBC ResultSet.
+ */
+public abstract class CoreResultSet {
+
+    protected final CoreStatement statement;
+
+    // Whether the result set does not have any rows.
+    protected boolean isEmptyResultSet = false;
+    // If the result set is open. Doesn't mean it has results.
+    protected boolean isOpen = false;
+    // Maximum number of rows as set by the statement
+    protected long maxRows;
+    // number of current row, starts at 1 (0 is used to represent loading data)
+    protected int row = 0;
+
+    protected CoreResultSet(CoreStatement statement) {
+        this.statement = statement;
+    }
+
+    /**
+     * Checks the status of the result set.
+     *
+     * @return true if it's ready to iterate over the result set; false otherwise.
+     */
+    public boolean isOpen() {
+        return isOpen;
+    }
+
+    /**
+     * @throws SQLException if not {@link #isOpen}
+     */
+    protected void checkOpen() throws SQLException {
+        if (!isOpen) {
+            throw new SQLException("ResultSet closed");
+        }
+    }
+}