better support for calcite types

Author: mspruc

wayang-api/wayang-api-sql/src/main/java/org/apache/wayang/api/sql/calcite/converter/functions/CallTreeFactory.java

@@ -87,11 +87,6 @@ class Literal implements Node {
     final Serializable value;
 
     Literal(final RexLiteral literal) {
-        System.out.println(literal.getValue().getClass());
-        System.out.println(literal.getValue2().getClass());
-        System.out.println(literal.getValue3().getClass());
-        System.out.println(literal.getValue4().getClass());
-
         value = switch (literal.getTypeName()) {
             case DATE         -> literal.getValueAs(Calendar.class);
             case INTEGER      -> literal.getValueAs(Double.class);

wayang-api/wayang-api-sql/src/main/java/org/apache/wayang/api/sql/calcite/converter/functions/FilterPredicateImpl.java

@@ -27,6 +27,7 @@
 import org.apache.calcite.runtime.SqlFunctions;
 import org.apache.calcite.sql.SqlKind;
 import org.apache.calcite.util.DateString;
+import org.apache.calcite.util.NlsString;
 import org.apache.wayang.basic.data.Record;
 import org.apache.wayang.core.function.FunctionDescriptor;
 import org.apache.wayang.core.function.FunctionDescriptor.SerializableFunction;
@@ -156,7 +157,9 @@ private boolean isEqualTo(final Object o1, final Object o2) {
             return (double) calendar.getTime().getTime();
         } else if (field instanceof final String string) {
             return string;
-        } else if (field instanceof final Character character) {
+        } else if (field instanceof final NlsString nlsString) {
+            return nlsString.getValue();
+        }  else if (field instanceof final Character character) {
             return character.toString();
         } else if (field instanceof final DateString dateString) {
             return (double) dateString.getMillisSinceEpoch();