fixes #195 foreach element outputs open and close values even when the passed collection is empty.

Author: harawata

src/main/java/org/apache/ibatis/scripting/xmltags/ForEachSqlNode.java

@@ -52,6 +52,9 @@ public ForEachSqlNode(Configuration configuration, SqlNode contents, String coll
   public boolean apply(DynamicContext context) {
     Map<String, Object> bindings = context.getBindings();
     final Iterable<?> iterable = evaluator.evaluateIterable(collectionExpression, bindings);
+    if (!iterable.iterator().hasNext()) {
+      return true;
+    }
     boolean first = true;
     applyOpen(context);
     int i = 0;

src/test/java/org/apache/ibatis/builder/xml/dynamic/DynamicSqlSourceTest.java

@@ -317,6 +317,20 @@ public void shouldIterateOnceForEachItemInCollection() throws Exception {
     assertEquals("__frch_item_2", boundSql.getParameterMappings().get(2).getProperty());
   }
 
+  @Test
+  public void shouldSkipForEachWhenCollectionIsEmpty() throws Exception {
+    final HashMap<String, Integer[]> parameterObject = new HashMap<String, Integer[]>() {{
+        put("array", new Integer[] {});
+    }};
+    final String expected = "SELECT * FROM BLOG";
+    DynamicSqlSource source = createDynamicSqlSource(new TextSqlNode("SELECT * FROM BLOG"),
+        new ForEachSqlNode(new Configuration(), mixedContents(
+            new TextSqlNode("#{item}")), "array", null, "item", "WHERE id in (", ")", ","));
+    BoundSql boundSql = source.getBoundSql(parameterObject);
+    assertEquals(expected, boundSql.getSql());
+    assertEquals(0, boundSql.getParameterMappings().size());
+  }
+
   @Test
   public void shouldPerformStrictMatchOnForEachVariableSubstitution() throws Exception {
     final Map<String, Object> param = new HashMap<String, Object>();