From d14be82d2b549dc5bd252ad0f87b2772447d65e2 Mon Sep 17 00:00:00 2001
From: Tony Tam <fehguy@gmail.com>
Date: Fri, 6 Nov 2015 16:54:07 -0800
Subject: [PATCH] added null check for #132

---
 .../parser/processors/ExternalRefProcessor.java     | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/modules/swagger-parser/src/main/java/io/swagger/parser/processors/ExternalRefProcessor.java b/modules/swagger-parser/src/main/java/io/swagger/parser/processors/ExternalRefProcessor.java
index 639370675a..50f13f1e1f 100644
--- a/modules/swagger-parser/src/main/java/io/swagger/parser/processors/ExternalRefProcessor.java
+++ b/modules/swagger-parser/src/main/java/io/swagger/parser/processors/ExternalRefProcessor.java
@@ -60,14 +60,15 @@ public String processRefToExternalDefinition(String $ref, RefFormat refFormat) {
             //If this is a new model, then check it for other sub references
             //Loop the properties and recursively call this method;
             Map<String, Property> subProps = model.getProperties();
-            for(Map.Entry<String,Property> prop: subProps.entrySet()){
-            	if(prop.getValue() instanceof RefProperty){
-            		RefProperty subRef = (RefProperty)prop.getValue();
-            		subRef.set$ref(processRefToExternalDefinition(subRef.get$ref(),subRef.getRefFormat()));
-            	}            	
+            if(subProps != null) {
+                for (Map.Entry<String, Property> prop : subProps.entrySet()) {
+                    if (prop.getValue() instanceof RefProperty) {
+                        RefProperty subRef = (RefProperty) prop.getValue();
+                        subRef.set$ref(processRefToExternalDefinition(subRef.get$ref(), subRef.getRefFormat()));
+                    }
+                }
             }
             swagger.addDefinition(newRef, model);
-
         }
 
         return newRef;