Reduce some duplication (by more duplication)

DynamoDB.scala.patch

diff --git a/dynamodb/src/main/scala/io/atlassian/aws/dynamodb/DynamoDB.scala b/dynamodb/src/main/scala/io/atlassian/aws/dynamodb/DynamoDB.scala
index e87be02..8331411 100644
--- a/dynamodb/src/main/scala/io/atlassian/aws/dynamodb/DynamoDB.scala
+++ b/dynamodb/src/main/scala/io/atlassian/aws/dynamodb/DynamoDB.scala
@@ -120,19 +120,7 @@ object DynamoDB {
   def query[PK, V](ck: Column[PK], cv: Column[V])(q: QueryImpl): DynamoDBAction[Page[PK, V]] =
     DynamoDBAction.withClient {
       _.query(q.asQueryRequest)
-    }.flatMap { res =>
-      DynamoDBAction.attempt {
-        res.getItems.asScala.toList.traverse[Attempt, V] {
-          cv.unmarshall.unmarshall
-        }.map { vs =>
-          Page(vs,
-            Option(res.getLastEvaluatedKey).flatMap {
-              lastKey => ck.unmarshall(lastKey.asScala.toMap).toOption
-            }
-          )
-        }
-      }
-    }
+    }.flatMap( _.decodeAsPage(ck, cv) )
 
   /**
    * Scan a table, with pagination.
@@ -143,19 +131,7 @@ object DynamoDB {
   def scan[PK, V](ck: Column[PK], cv: Column[V])(q: ScanImpl): DynamoDBAction[Page[PK, V]] =
     DynamoDBAction.withClient {
       _.scan(q.asScanRequest)
-    }.flatMap { res =>
-      DynamoDBAction.attempt {
-        res.getItems.asScala.toList.traverse[Attempt, V] { v =>
-          cv.unmarshall.unmarshall(v)
-        }.map { vs =>
-          Page(vs,
-            Option(res.getLastEvaluatedKey).flatMap {
-              lastKey => ck.unmarshall(lastKey.asScala.toMap).toOption
-            }
-          )
-        }
-      }
-    }
+    }.flatMap( _.decodeAsPage(ck, cv) )
 
   def tableExists(tableName: String): DynamoDBAction[Boolean] =
     withClient { client =>
@@ -259,6 +235,28 @@ object DynamoDB {
       _.deleteTable(Table.name)
     }
 
+  /** Describes the bit of the ScanResult and QueryResult classes which we use to read the results.
+    */
+  private type ReadOperationResult = {
+    def getItems(): java.util.List[java.util.Map[java.lang.String, AttributeValue]]
+    def getLastEvaluatedKey(): java.util.Map[java.lang.String, AttributeValue]
+  }
+
+  private implicit class ResultWithItems[Result <: ReadOperationResult](result: Result) {
+    def decodeAsPage[PK, V](ck: Column[PK], cv: Column[V]): DynamoDBAction[Page[PK, V]] =
+      DynamoDBAction.attempt {
+        result.getItems().asScala.toList.traverse[Attempt, V] {
+          cv.unmarshall.unmarshall
+        }.map { vs =>
+          Page(vs,
+            Option(result.getLastEvaluatedKey())flatMap {
+              lastKey => ck.unmarshall(lastKey.asScala.toMap).toOption
+            }
+          )
+        }
+      }
+  }
+
   sealed trait ReadConsistency
   object ReadConsistency {
     case object Strong extends ReadConsistency

Hmm. Except for the reflection I don't mind this new version.