From 5603b0703e9b9f72a5a5da0c8595e96fe1157c43 Mon Sep 17 00:00:00 2001
From: Gustavo Durand <gdurand@iq.harvard.edu>
Date: Mon, 20 Jun 2016 17:48:24 -0400
Subject: [PATCH] fixed null pointer on optional values for citation (and used
 functional programming)

---
 .../java/edu/harvard/iq/dataverse/DataCitation.java   | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/src/main/java/edu/harvard/iq/dataverse/DataCitation.java b/src/main/java/edu/harvard/iq/dataverse/DataCitation.java
index 9ee3d0a89f8..b12dd3b63b3 100644
--- a/src/main/java/edu/harvard/iq/dataverse/DataCitation.java
+++ b/src/main/java/edu/harvard/iq/dataverse/DataCitation.java
@@ -100,9 +100,12 @@ public DataCitation(DatasetVersion dsv) {
         UNF = dsv.getUNF();
 
         // optional values
-        for (DatasetFieldType dsfType : dsv.getDataset().getOwner().getCitationDatasetFieldTypes()) {
-            optionalValues.add(dsv.getDatasetField(dsfType));
-        }
+        dsv.getDataset().getOwner().getCitationDatasetFieldTypes().stream()
+                .map(dsfType -> dsv.getDatasetField(dsfType))
+                .filter(dsf -> dsf != null)
+                .forEach(dsf -> {
+                    optionalValues.add(dsf);
+                });
 
     }
 
@@ -166,7 +169,7 @@ public String toString(boolean html) {
             } else {
                 displayValue = formatString(dsf.getDisplayValue(), html);
             }
-            
+
             citation.append(" [").append(dsf.getDatasetFieldType().getDisplayName()).append(":")
                     .append(displayValue)
                     .append("]");