fixed sonar rule violations

src/main/java/com/alibaba/druid/sql/dialect/oracle/ast/stmt/OracleCommitStatement.java

@@ -27,9 +27,7 @@ public class OracleCommitStatement extends OracleStatementImpl {
 
     @Override
     public void accept0(OracleASTVisitor visitor) {
-        if (visitor.visit(this)) {
-
-        }
+        visitor.visit(this);
         visitor.endVisit(this);
     }
 

src/main/java/com/alibaba/druid/sql/dialect/postgresql/parser/PGExprParser.java

@@ -73,9 +73,9 @@ public class PGExprParser extends SQLExprParser{
 
             over.setOrderBy(parseOrderBy());
             
-            if (over.getOrderBy() != null) {
-            	//TODO window
-            }
+            // if (over.getOrderBy() != null) {
+            // //TODO window
+            // }
         	
         	accept(Token.RPAREN);
         	aggregateExpr.setOver(over);

src/main/java/com/alibaba/druid/sql/dialect/postgresql/parser/PGSelectParser.java

@@ -147,9 +147,6 @@ public class PGSelectParser extends SQLSelectParser {
 
             if (lexer.token() == Token.ROW || lexer.token() == Token.ROWS) {
                 lexer.nextToken();
-            } else {
-                // TODO
-                // throw new ParserException("expect 'ROW' or 'ROWS'");
             }
         }
 

src/main/java/com/alibaba/druid/sql/dialect/sqlserver/ast/Top.java

@@ -55,9 +55,8 @@ public class Top extends SQLServerObjectImpl {
 
     @Override
     public void accept0(SQLServerASTVisitor visitor) {
-        if (visitor.visit(this)) {
-
-        }
+        visitor.visit(this);
+        visitor.endVisit(this);
     }
 
 }

src/main/java/com/alibaba/druid/sql/dialect/sqlserver/ast/expr/SQLServerObjectReferenceExpr.java

@@ -60,9 +60,7 @@ public class SQLServerObjectReferenceExpr extends SQLServerObjectImpl implements
 
     @Override
     public void accept0(SQLServerASTVisitor visitor) {
-        if (visitor.visit(this)) {
-
-        }
+        visitor.visit(this);
         visitor.endVisit(this);
     }