[#1723] Add Factory.fetchLazy(ResultSet)

jOOQ-test/src/org/jooq/test/_/testcases/FetchTests.java

@@ -1132,10 +1132,25 @@ extends BaseTest<A, AP, B, S, B2S, BS, L, X, DATE, BOOL, D, T, U, I, IPK, T658,
     @Test
     public void testFetchResultSet() throws Exception {
         for (int i = 0; i < 2; i++) {
+            // Fetching ResultSets into Results
             assertEquals(
                 create().fetch("select * from t_author order by id"),
                 create().fetch(create().resultQuery("select * from t_author order by id").fetchResultSet()));
 
+            // [#1723] Fetching ResultSets into Cursors
+            Cursor<Record> c1 = create().fetchLazy("select * from t_author order by id");
+            Cursor<Record> c2 = create().fetchLazy(create().resultQuery("select * from t_author order by id").fetchResultSet());
+
+            for (int j = 0; j < 2; j++) {
+                assertTrue(c1.hasNext());
+                assertTrue(c2.hasNext());
+                assertEquals(c1.fetchOne(), c2.fetchOne());
+            }
+
+            assertFalse(c1.hasNext());
+            assertFalse(c2.hasNext());
+
+            // Fetching ResultSets
             ResultSet rs = create().resultQuery("select * from t_author order by id").fetchResultSet();
             assertTrue(rs.next());
             assertEquals(1, rs.getInt(1));

jOOQ/src/main/java/org/jooq/FactoryOperations.java

@@ -221,6 +221,10 @@ public interface FactoryOperations extends Configuration {
      * Fetch all data from a JDBC {@link ResultSet} and transform it to a jOOQ
      * {@link Result}. After fetching all data, the JDBC ResultSet will be
      * closed.
+     * <p>
+     * Use {@link #fetchLazy(ResultSet)}, to fetch one <code>Record</code> at a
+     * time, instead of load the entire <code>ResultSet</code> into a jOOQ
+     * <code>Result</code> at once.
      *
      * @param rs The JDBC ResultSet to fetch data from
      * @return The resulting jOOQ Result
@@ -229,6 +233,21 @@ public interface FactoryOperations extends Configuration {
     @Support
     Result<Record> fetch(ResultSet rs) throws DataAccessException;
 
+    /**
+     * Fetch all data from a JDBC {@link ResultSet} and transform it to a jOOQ
+     * {@link Result}. After fetching all data, the JDBC ResultSet will be
+     * closed.
+     * <p>
+     * Use {@link #fetch(ResultSet)}, to load the entire <code>ResultSet</code>
+     * into a jOOQ <code>Result</code> at once.
+     *
+     * @param rs The JDBC ResultSet to fetch data from
+     * @return The resulting jOOQ Result
+     * @throws DataAccessException if something went wrong executing the query
+     */
+    @Support
+    Cursor<Record> fetchLazy(ResultSet rs) throws DataAccessException;
+
     /**
      * Fetch all data from a CSV string.
      * <p>

jOOQ/src/main/java/org/jooq/impl/Factory.java

@@ -1682,15 +1682,18 @@ public class Factory implements FactoryOperations {
     // -------------------------------------------------------------------------
 
     /**
-     * Fetch all data from a JDBC {@link ResultSet} and transform it to a jOOQ
-     * {@link Result}. After fetching all data, the JDBC ResultSet will be
-     * closed.
-     *
-     * @param rs The JDBC ResultSet to fetch data from
-     * @return The resulting jOOQ Result
+     * {@inheritDoc}
      */
     @Override
     public final Result<Record> fetch(ResultSet rs) {
+        return fetchLazy(rs).fetch();
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public final Cursor<Record> fetchLazy(ResultSet rs) {
         ExecuteContext ctx = new DefaultExecuteContext(this);
         ExecuteListener listener = new ExecuteListeners(ctx);
 
@@ -1698,7 +1701,7 @@ public class Factory implements FactoryOperations {
             FieldProvider fields = new MetaDataFieldProvider(this, rs.getMetaData());
 
             ctx.resultSet(rs);
-            return new CursorImpl<Record>(ctx, listener, fields).fetch();
+            return new CursorImpl<Record>(ctx, listener, fields);
         }
         catch (SQLException e) {
             ctx.sqlException(e);

jOOQ/src/main/java/org/jooq/impl/FactoryProxy.java

@@ -397,6 +397,11 @@ public final class FactoryProxy implements FactoryOperations {
         return getDelegate().fetch(rs);
     }
 
+    @Override
+    public final Cursor<Record> fetchLazy(ResultSet rs) {
+        return getDelegate().fetchLazy(rs);
+    }
+
     @Override
     public final Result<Record> fetchFromCSV(String string) {
         return null;