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-rw-r--r--policy-utils/src/main/java/org/openecomp/policy/drools/utils/OrderedServiceImpl.java33
1 files changed, 32 insertions, 1 deletions
diff --git a/policy-utils/src/main/java/org/openecomp/policy/drools/utils/OrderedServiceImpl.java b/policy-utils/src/main/java/org/openecomp/policy/drools/utils/OrderedServiceImpl.java
index 2747e85e..809d3679 100644
--- a/policy-utils/src/main/java/org/openecomp/policy/drools/utils/OrderedServiceImpl.java
+++ b/policy-utils/src/main/java/org/openecomp/policy/drools/utils/OrderedServiceImpl.java
@@ -22,6 +22,7 @@ package org.openecomp.policy.drools.utils;
import java.util.Collections;
import java.util.Comparator;
+import java.util.HashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.ServiceLoader;
@@ -80,7 +81,7 @@ public class OrderedServiceImpl<T extends OrderedService>
List<T> tmp = new LinkedList<T>();
for (T service : serviceLoader)
{
- tmp.add(service);
+ tmp.add((T)getSingleton(service));
}
// Sort the list according to sequence number, and then alphabetically
@@ -114,4 +115,34 @@ public class OrderedServiceImpl<T extends OrderedService>
System.out.println("***** OrderedServiceImpl implementers:\n" + implementers);
return(implementers);
}
+
+ // use this to ensure that we only use one unique instance of each class
+ static private HashMap<Class,OrderedService> classToSingleton =
+ new HashMap<>();
+
+ /**
+ * If a service implements multiple APIs managed by 'ServiceLoader', a
+ * separate instance is created for each API. This method ensures that
+ * the first instance is used in all of the lists.
+ *
+ * @param service this is the object created by ServiceLoader
+ * @return the object to use in place of 'service'. If 'service' is the first
+ * object of this class created by ServiceLoader, it is returned. If not,
+ * the object of this class that was initially created is returned
+ * instead.
+ */
+ static private synchronized OrderedService
+ getSingleton(OrderedService service)
+ {
+ // see if we already have an instance of this class
+ OrderedService rval = classToSingleton.get(service.getClass());
+ if (rval == null)
+ {
+ // No previous instance of this class exists -- use the supplied
+ // instance, and place it in the table.
+ rval = service;
+ classToSingleton.put(service.getClass(), service);
+ }
+ return(rval);
+ }
}