improved sql format output

src/main/java/com/alibaba/druid/sql/ast/SQLObjectImpl.java

@@ -15,6 +15,7 @@
  */
 package com.alibaba.druid.sql.ast;
 
+import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -107,4 +108,70 @@ public abstract class SQLObjectImpl implements SQLObject {
     public Map<String, Object> getAttributesDirect() {
         return attributes;
     }
+    
+    @SuppressWarnings("unchecked")
+    public void addBeforeComment(String comment) {
+        if (attributes == null) {
+            attributes = new HashMap<String, Object>(1);
+        }
+        
+        List<String> comments = (List<String>) attributes.get("format.before_comment");
+        if (comments == null) {
+            comments = new ArrayList<String>(2);
+            attributes.put("format.before_comment", comments);
+        }
+        
+        comments.add(comment);
+    }
+    
+    @SuppressWarnings("unchecked")
+    public List<String> getBeforeCommentsDirect() {
+        if (attributes == null) {
+            return null;
+        }
+        
+        return (List<String>) attributes.get("format.before_comment");
+    }
+    
+    @SuppressWarnings("unchecked")
+    public void addAfterComment(String comment) {
+        if (attributes == null) {
+            attributes = new HashMap<String, Object>(1);
+        }
+        
+        List<String> comments = (List<String>) attributes.get("format.after_comment");
+        if (comments == null) {
+            comments = new ArrayList<String>(2);
+            attributes.put("format.after_comment", comments);
+        }
+        
+        comments.add(comment);
+    }
+    
+    @SuppressWarnings("unchecked")
+    public List<String> getAfterCommentsDirect() {
+        if (attributes == null) {
+            return null;
+        }
+        
+        return (List<String>) attributes.get("format.after_comment");
+    }
+    
+    public boolean hasBeforeComment() {
+        List<String> comments = getBeforeCommentsDirect();
+        if (comments == null) {
+            return false;
+        }
+        
+        return !comments.isEmpty();
+    }
+    
+    public boolean hasAfterComment() {
+        List<String> comments = getAfterCommentsDirect();
+        if (comments == null) {
+            return false;
+        }
+        
+        return !comments.isEmpty();
+    }
 }