From aa134fc423d454f7d8ee4aa192d2c4a1f3c6cce5 Mon Sep 17 00:00:00 2001
From: "Karl M. Davis" <karl@justdavis.com>
Date: Thu, 1 Jun 2017 03:17:38 -0400
Subject: [PATCH] Hacky but workable fix for race condition surfaced by
 If-None-Exists creates.

Some notes from other attempts I made to fix this in a less hacky way:

* Tried to @Autowire myResourceDaos from a setter (rather than using the annotation on a field), and initialize myResourceTypeToDao in that setter, instead. Couldn't get it to work: Spring started throwing odd bean dependency errors. Don't really understand why.
* Tried to move the exceptions being thrown on null getDao(Class) results into that method, but that was breaking a test case. Didn't investigate why.
---
 .../main/java/ca/uhn/fhir/jpa/dao/BaseHapiFhirDao.java | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/hapi-fhir-jpaserver-base/src/main/java/ca/uhn/fhir/jpa/dao/BaseHapiFhirDao.java b/hapi-fhir-jpaserver-base/src/main/java/ca/uhn/fhir/jpa/dao/BaseHapiFhirDao.java
index 072a6fe34b9..b8db560cabd 100644
--- a/hapi-fhir-jpaserver-base/src/main/java/ca/uhn/fhir/jpa/dao/BaseHapiFhirDao.java
+++ b/hapi-fhir-jpaserver-base/src/main/java/ca/uhn/fhir/jpa/dao/BaseHapiFhirDao.java
@@ -636,19 +636,21 @@ public abstract class BaseHapiFhirDao<T extends IBaseResource> implements IDao {
 	@SuppressWarnings("unchecked")
 	public <R extends IBaseResource> IFhirResourceDao<R> getDao(Class<R> theType) {
 		if (myResourceTypeToDao == null) {
-			myResourceTypeToDao = new HashMap<Class<? extends IBaseResource>, IFhirResourceDao<?>>();
+			Map<Class<? extends IBaseResource>, IFhirResourceDao<?>> theResourceTypeToDao = new HashMap<Class<? extends IBaseResource>, IFhirResourceDao<?>>();
 			for (IFhirResourceDao<?> next : myResourceDaos) {
-				myResourceTypeToDao.put(next.getResourceType(), next);
+				theResourceTypeToDao.put(next.getResourceType(), next);
 			}
 
 			if (this instanceof IFhirResourceDao<?>) {
 				IFhirResourceDao<?> thiz = (IFhirResourceDao<?>) this;
-				myResourceTypeToDao.put(thiz.getResourceType(), thiz);
+				theResourceTypeToDao.put(thiz.getResourceType(), thiz);
 			}
 
+			myResourceTypeToDao = theResourceTypeToDao;
 		}
 
-		return (IFhirResourceDao<R>) myResourceTypeToDao.get(theType);
+		IFhirResourceDao<R> dao = (IFhirResourceDao<R>) myResourceTypeToDao.get(theType);
+		return dao;
 	}
 
 	@Override