fix: Bucket name is not required

Author: afranken

server/src/main/kotlin/com/adobe/testing/s3mock/dto/Bucket.kt

@@ -31,7 +31,7 @@ data class Bucket(
   @param:JsonProperty("CreationDate", namespace = "http://s3.amazonaws.com/doc/2006-03-01/")
   val creationDate: String?,
   @param:JsonProperty("Name", namespace = "http://s3.amazonaws.com/doc/2006-03-01/")
-  val name: String,
+  val name: String?,
   @JsonIgnore
   val path: Path?
 ) {

server/src/main/kotlin/com/adobe/testing/s3mock/service/BucketService.kt

@@ -43,6 +43,7 @@ import com.adobe.testing.s3mock.util.AwsHttpHeaders.X_AMZ_BUCKET_LOCATION_TYPE
 import software.amazon.awssdk.utils.http.SdkHttpUtils.urlEncodeIgnoreSlashes
 import java.util.UUID
 import java.util.concurrent.ConcurrentHashMap
+import kotlin.let
 
 open class BucketService(
   private val bucketStore: BucketStore,
@@ -92,7 +93,9 @@ open class BucketService(
     if (buckets.size > maxBuckets) {
       nextContinuationToken = UUID.randomUUID().toString()
       buckets = buckets.subList(0, maxBuckets)
-      listBucketsPagingStateCache[nextContinuationToken] = buckets[maxBuckets - 1].name
+      buckets[maxBuckets - 1].name?.let {
+        listBucketsPagingStateCache[nextContinuationToken] = it
+      }
     }
 
     return ListAllMyBucketsResult(Owner.DEFAULT_OWNER, Buckets(buckets), prefix, nextContinuationToken)

server/src/main/kotlin/com/adobe/testing/s3mock/service/ServiceBase.kt

@@ -93,15 +93,12 @@ abstract class ServiceBase {
 
     fun <T> filterBy(
       contents: List<T>,
-      selector: (T) -> String,
+      selector: (T) -> String?,
       compareTo: String?
-    ): List<T> {
-      return if (!compareTo.isNullOrEmpty()) {
-        contents.filter { selector(it) > compareTo }
-      } else {
-        contents
-      }
-    }
+    ): List<T> =
+      compareTo?.let { threshold ->
+        contents.filter { selector(it)?.let { candidate -> candidate > threshold } == true }
+      } ?: contents
 
     fun <T> filterBy(
       contents: List<T>,
@@ -117,11 +114,11 @@ abstract class ServiceBase {
 
     fun <T> filterBy(
       contents: List<T>,
-      selector: (T) -> String,
+      selector: (T) -> String?,
       prefixes: List<String>?
     ): List<T> {
       return if (!prefixes.isNullOrEmpty()) {
-        contents.filter { content -> prefixes.none { prefix -> selector(content).startsWith(prefix) } }
+        contents.filter { content -> prefixes.none { prefix -> selector(content)?.startsWith(prefix) ?: false } }
       } else {
         contents
       }