use predicate instead of method

extensions/data-plane/data-plane-aws-s3/src/main/java/org/eclipse/edc/connector/dataplane/aws/s3/S3DataSource.java

@@ -27,8 +27,8 @@
 
 import java.io.InputStream;
 import java.util.ArrayList;
-import java.util.Collection;
 import java.util.List;
+import java.util.function.Predicate;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
@@ -109,7 +109,9 @@ private List<S3Object> fetchPrefixedS3Objects() {
 
             var response = client.listObjectsV2(listObjectsRequest);
 
-            s3Objects.addAll(filterOutFolderFile(response.contents()));
+            Predicate<S3Object> isFile = object -> !object.key().endsWith("/");
+
+            s3Objects.addAll(response.contents().stream().filter(isFile).collect(Collectors.toList()));
 
             continuationToken = response.nextContinuationToken();
 
@@ -118,10 +120,6 @@ private List<S3Object> fetchPrefixedS3Objects() {
         return s3Objects;
     }
 
-    private Collection<S3Object> filterOutFolderFile(List<S3Object> contents) {
-        return contents.stream().filter(object -> !object.key().endsWith("/")).collect(Collectors.toSet());
-    }
-
     @Override
     public void close() {
         client.close();