Fix NPE when mapping insert / delete events. (#143)

Insert event does not have oldImage. Remove event does not have newImage. At this moment library just throws nullPointerException

Co-authored-by: Carl Zogheib <[email protected]>

Author: senioroman4uk

aws-lambda-java-events-sdk-transformer/src/main/java/com/amazonaws/services/lambda/runtime/events/transformers/dynamodb/DynamodbStreamRecordTransformer.java

@@ -5,18 +5,23 @@
 public class DynamodbStreamRecordTransformer {
 
     public static StreamRecord toStreamRecordV2(final com.amazonaws.services.lambda.runtime.events.models.dynamodb.StreamRecord streamRecord) {
+
         return StreamRecord.builder()
                 .approximateCreationDateTime(
-                        streamRecord.getApproximateCreationDateTime().toInstant()
+                    streamRecord.getApproximateCreationDateTime().toInstant()
                 )
                 .keys(
-                        DynamodbAttributeValueTransformer.toAttributeValueMapV2(streamRecord.getKeys())
+                    DynamodbAttributeValueTransformer.toAttributeValueMapV2(streamRecord.getKeys())
                 )
                 .newImage(
-                        DynamodbAttributeValueTransformer.toAttributeValueMapV2(streamRecord.getNewImage())
+                    streamRecord.getNewImage() != null
+                        ? DynamodbAttributeValueTransformer.toAttributeValueMapV2(streamRecord.getNewImage())
+                        : null
                 )
                 .oldImage(
-                        DynamodbAttributeValueTransformer.toAttributeValueMapV2(streamRecord.getOldImage())
+                    streamRecord.getOldImage() != null
+                        ? DynamodbAttributeValueTransformer.toAttributeValueMapV2(streamRecord.getOldImage())
+                        : null
                 )
                 .sequenceNumber(streamRecord.getSequenceNumber())
                 .sizeBytes(streamRecord.getSizeBytes())

aws-lambda-java-events-sdk-transformer/src/test/java/com/amazonaws/services/lambda/runtime/events/transformers/dynamodb/DynamodbStreamRecordTransformerTest.java

@@ -101,4 +101,24 @@ public void testToStreamRecordV2() {
         StreamRecord convertedStreamRecord = DynamodbStreamRecordTransformer.toStreamRecordV2(streamRecord_event);
         Assertions.assertEquals(streamRecord_v2, convertedStreamRecord);
     }
+
+    @Test
+    public void testToStreamRecordV2WhenOldImageIsNull() {
+        com.amazonaws.services.lambda.runtime.events.models.dynamodb.StreamRecord streamRecord = streamRecord_event.clone();
+        streamRecord.setOldImage(null);
+
+        Assertions.assertDoesNotThrow(() -> {
+            DynamodbStreamRecordTransformer.toStreamRecordV2(streamRecord);
+        });
+    }
+
+    @Test
+    public void testToStreamRecordV2WhenNewImageIsNull() {
+        com.amazonaws.services.lambda.runtime.events.models.dynamodb.StreamRecord streamRecord = streamRecord_event.clone();
+        streamRecord.setNewImage(null);
+
+        Assertions.assertDoesNotThrow(() -> {
+            DynamodbStreamRecordTransformer.toStreamRecordV2(streamRecord);
+        });
+    }
 }