fix: make analytic expression visitor null-safe (#1944)

src/main/java/net/sf/jsqlparser/expression/ExpressionVisitorAdapter.java

@@ -64,6 +64,8 @@
 import net.sf.jsqlparser.statement.select.UnPivot;
 import net.sf.jsqlparser.statement.select.WithItem;
 
+import java.util.Optional;
+
 @SuppressWarnings({"PMD.CyclomaticComplexity", "PMD.UncommentedEmptyMethodBody"})
 public class ExpressionVisitorAdapter
  implements ExpressionVisitor, PivotVisitor, SelectItemVisitor {
@@ -382,11 +384,19 @@ public void visit(AnalyticExpression expr) {
  element.getExpression().accept(this);
  }
  }
-
  if (expr.getWindowElement() != null) {
- expr.getWindowElement().getRange().getStart().getExpression().accept(this);
- expr.getWindowElement().getRange().getEnd().getExpression().accept(this);
- expr.getWindowElement().getOffset().getExpression().accept(this);
+ /*
+ * Visit expressions from the range and offset of the window element. Do this using
+ * optional chains, because several things down the tree can be null e.g. the
+ * expression. So, null-safe versions of e.g.:
+ * expr.getWindowElement().getOffset().getExpression().accept(this);
+ */
+ Optional.ofNullable(expr.getWindowElement().getRange()).map(WindowRange::getStart)
+ .map(WindowOffset::getExpression).ifPresent(e -> e.accept(this));
+ Optional.ofNullable(expr.getWindowElement().getRange()).map(WindowRange::getEnd)
+ .map(WindowOffset::getExpression).ifPresent(e -> e.accept(this));
+ Optional.ofNullable(expr.getWindowElement().getOffset())
+ .map(WindowOffset::getExpression).ifPresent(e -> e.accept(this));
  }
  }
 

src/test/java/net/sf/jsqlparser/expression/ExpressionVisitorAdapterTest.java

@@ -259,4 +259,13 @@ public void visit(AllTableColumns all) {
  assertNotNull(holder[0]);
  assertEquals("a.*", holder[0].toString());
  }
+
+ @Test
+ public void testAnalyticExpressionWithPartialWindowElement() throws JSQLParserException {
+ ExpressionVisitorAdapter adapter = new ExpressionVisitorAdapter();
+ Expression expression = CCJSqlParserUtil.parseExpression(
+ "SUM(\"Spent\") OVER (PARTITION BY \"ID\" ORDER BY \"Name\" ASC ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING)");
+
+ expression.accept(adapter);
+ }
 }