Fix issue in jar.

Author: Ghislain Fourny

src/jsoniq/jars/rumbledb-2.0.0.jar

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:6e55a44233af9e937db13f5db036521860a74f4396b88c1a82d085f1b6933ef0
-size 33054930
+oid sha256:f559c7bc57eb22ba5257a6ba6c79d3fd4cebd89f5cebe6dba0bca0ff68f724e3
+size 33207084

src/jsoniq/sequence.py

@@ -54,10 +54,16 @@ def rdd(self):
         return self._rumblesession.lastResult
 
     def df(self):
+        if (not "DataFrame" in self._jsequence.availableOutputs()):
+            sys.stderr.write(self.schema_str)
+            return None
         self._rumblesession.lastResult = DataFrame(self._jsequence.getAsDataFrame(), self._sparksession)
         return self._rumblesession.lastResult
 
     def pdf(self):
+        if (not "DataFrame" in self._jsequence.availableOutputs()):
+            sys.stderr.write(self.schema_str)
+            return None
         self._rumblesession.lastResult = self.df().toPandas()
         return self._rumblesession.lastResult