sruehl commented on a change in pull request #8: cleanup warnings in plc4j-api,
plc4j-core, dummy-driver
URL: https://github.com/apache/incubator-plc4x/pull/8#discussion_r170832548
##########
File path:
plc4j/api/src/main/java/org/apache/plc4x/java/api/messages/specific/TypeSafePlcReadResponse.java
##########
@@ -59,17 +59,49 @@ public TypeSafePlcReadResponse(TypeSafePlcReadRequest<T>
request, List<ReadRespo
return (Optional<ReadResponseItem<T>>) super.getResponseItem();
}
+ /**
+ * Cast or convert a PlcReadResponse to a TypeSafePlcReadReadResponse<T>.
+ *
+ * WARNING: this is inherently a non-type-safe operation. It was
introduced
+ * to serve the implementation of
PlcReader.read(TypeSafePlcReadRequest<T>).
+ * Additional use of it is not recommended. This interface is subject to
change.
+ *
+ * @param plcReadResponse the response implicitly with items of type T
+ * @return TypeSafePlcReadReadResponse<T>
+ */
@SuppressWarnings("unchecked")
public static <T> TypeSafePlcReadResponse<T> of(PlcReadResponse
plcReadResponse) {
+ // BUG: there seems to be no checking that the readResponse/items
+ // in fact are for type T.
+ // I don't even think it's possible to do that with the current 'of()'
signature
+ // and plcReadResponse content.
+ //
+ // The only consolation is that currently, 'of()' is only really used
in the
+ // impl of PlcReader.read(TypeSafePlcReadRequest<T>) and that case
guarantees
+ // that all items are a T. plcReadResponse isa
TypeSafePlcReadResponse in
+ // this case.
+ //
+ // Maybe we just need to doc that this conversion is unsafe and/or
rename
+ // the method to "unsafeOf()"?
+ // Or, if there were an AbstractPlcReader<T>, that could internally
implement
+ // this method without exposing this generally it, the PlcReader
interface
+ // could remove the default implementation of
read(TypeSafePlcReadRequest<T>),
+ // and protocol implementations could extend AbstractPlcReader.
+ //
+ // FWIW, in one case there is some checking that all of the items in a
response
+ // are at least of the same type.
+
if (plcReadResponse instanceof TypeSafePlcReadResponse) {
- return (TypeSafePlcReadResponse) plcReadResponse;
+ // Warning: no validation that everything in the response is a T.
Review comment:
then we would need to check here if the requested `Class class` is equals to
the supplied type
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