refactor merger into ShardingResultSet 17th version, refactor OrderByValue

sharding-jdbc-core/src/main/java/com/dangdang/ddframe/rdb/sharding/merger/stream/OrderByStreamResultSetMerger.java

@@ -49,7 +49,7 @@ public class OrderByStreamResultSetMerger extends AbstractStreamResultSetMerger
     private void orderResultSetsToQueue(final Collection<ResultSet> resultSets) throws SQLException {
         for (ResultSet each : resultSets) {
             OrderByValue orderByValue = new OrderByValue(each, orderByItems);
-            if (orderByValue.next(false)) {
+            if (orderByValue.next()) {
                 orderByValuesQueue.offer(orderByValue);
             }
         }
@@ -63,16 +63,14 @@ public class OrderByStreamResultSetMerger extends AbstractStreamResultSetMerger
         if (orderByValuesQueue.isEmpty()) {
             return false;
         }
-        OrderByValue firstResultSet = orderByValuesQueue.poll();
-        setCurrentResultSet(firstResultSet.getResultSet());
-        if (firstResultSet.next(isFirstNext)) {
-            orderByValuesQueue.offer(firstResultSet);
+        if (isFirstNext) {
+            isFirstNext = false;
+            return true;
+        }
+        OrderByValue firstOrderByValue = orderByValuesQueue.poll();
+        if (firstOrderByValue.next()) {
+            orderByValuesQueue.offer(firstOrderByValue);
         }
-        isFirstNext = false;
-        return hasNext();
-    }
-    
-    private boolean hasNext() {
         if (orderByValuesQueue.isEmpty()) {
             return false;
         }

sharding-jdbc-core/src/main/java/com/dangdang/ddframe/rdb/sharding/merger/stream/OrderByValue.java

@@ -47,12 +47,11 @@ public final class OrderByValue implements Comparable<OrderByValue> {
     /**
      * 遍历下一个结果集游标.
      * 
-     * @param isFirstNext 是否第一次调用
      * @return 是否有下一个结果集
      * @throws SQLException SQL异常
      */
-    public boolean next(final boolean isFirstNext) throws SQLException {
-        boolean result = isFirstNext || resultSet.next();
+    public boolean next() throws SQLException {
+        boolean result = resultSet.next();
         orderValues = result ? getOrderValues() : Collections.<Comparable<?>>emptyList();
         return result;
     }

sharding-jdbc-core/src/test/java/com/dangdang/ddframe/rdb/sharding/merger/row/OrderByValueTest.java

@@ -39,10 +39,10 @@ public final class OrderByValueTest {
     public void assertCompareToForAsc() throws SQLException {
         OrderByValue orderByValue1 = new OrderByValue(
                 createResultSet("order_1", "order_2", "other_1"), Arrays.asList(new OrderItem(1, OrderType.ASC), new OrderItem(2, OrderType.ASC)));
-        orderByValue1.next(false);
+        orderByValue1.next();
         OrderByValue orderByValue2 = new OrderByValue(
                 createResultSet("order_3", "order_4", "other_2"), Arrays.asList(new OrderItem(1, OrderType.ASC), new OrderItem(2, OrderType.ASC)));
-        orderByValue2.next(false);
+        orderByValue2.next();
         assertTrue(orderByValue1.compareTo(orderByValue2) < 0);
     }
     
@@ -50,10 +50,10 @@ public final class OrderByValueTest {
     public void assertCompareToForDesc() throws SQLException {
         OrderByValue orderByValue1 = new OrderByValue(
                 createResultSet("order_1", "order_2", "other_1"), Arrays.asList(new OrderItem(1, OrderType.DESC), new OrderItem(2, OrderType.DESC)));
-        orderByValue1.next(false);
+        orderByValue1.next();
         OrderByValue orderByValue2 = new OrderByValue(
                 createResultSet("order_3", "order_4", "other_2"), Arrays.asList(new OrderItem(1, OrderType.DESC), new OrderItem(2, OrderType.DESC)));
-        orderByValue2.next(false);
+        orderByValue2.next();
         assertTrue(orderByValue1.compareTo(orderByValue2) > 0);
     }
     
@@ -61,7 +61,7 @@ public final class OrderByValueTest {
     public void assertCompareToWhenEqual() throws SQLException {
         OrderByValue orderByValue = new OrderByValue(
                 createResultSet("order_1", "order_2", "other"), Arrays.asList(new OrderItem(1, OrderType.DESC), new OrderItem(2, OrderType.DESC)));
-        orderByValue.next(false);
+        orderByValue.next();
         assertThat(orderByValue.compareTo(orderByValue), is(0));
     }