diff options
Diffstat (limited to 'policy-utils/src')
| -rw-r--r-- | policy-utils/src/main/java/org/openecomp/policy/drools/utils/OrderedServiceImpl.java | 33 |
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); + } } |