Replace the chain of if/else with a switch expression.

Author: thomasturrell

xapi-client/src/main/java/dev/learning/xapi/client/StatementHttpMessageWriter.java

@@ -164,14 +164,16 @@ private List<Object> getParts(Object object) {
 
     final var list = new ArrayList<>();
 
-    Stream<Attachment> attachments;
-    if (object instanceof final Statement statement) {
-      attachments = getRealAttachments(statement);
-    } else if (object instanceof final List<?> statements
-        && !statements.isEmpty()
-        && statements.get(0) instanceof Statement) {
-      attachments = ((List<Statement>) statements).stream().flatMap(this::getRealAttachments);
-    } else {
+    final Stream<Attachment> attachments =
+        switch (object) {
+          case Statement statement -> getRealAttachments(statement);
+          case List<?> statements
+              when !statements.isEmpty() && statements.get(0) instanceof Statement ->
+                  ((List<Statement>) statements).stream().flatMap(this::getRealAttachments);
+          default -> null;
+        };
+
+    if (attachments == null) {
       // The object is not a statement or list of statements
       return list;
     }