Deny subsequent lock()

This is the final step of separating the lock "refresh" operation
from the original "lock" operation.  This step entails rejecting
subsequent "lock" requests, even by the same owner, when a resource
is already locked; "refresh" should now be used, instead, to extend
a lock.
Modified comments to indicate that the lock can only be extended
using "refresh".

Change-Id: I406cf60c076dbce87afbd94fb301732359dbd2db
Issue-ID: POLICY-872
Signed-off-by: Jim Hahn <jrh3@att.com>

2 files changed, 7 insertions, 12 deletions

diff --git a/policy-core/src/main/java/org/onap/policy/drools/core/lock/PolicyResourceLockFeatureAPI.java b/policy-core/src/main/java/org/onap/policy/drools/core/lock/PolicyResourceLockFeatureAPI.java
index ba6fe856..5aee490f 100644
--- a/policy-core/src/main/java/org/onap/policy/drools/core/lock/PolicyResourceLockFeatureAPI.java
+++ b/policy-core/src/main/java/org/onap/policy/drools/core/lock/PolicyResourceLockFeatureAPI.java
@@ -71,8 +71,7 @@ public interface PolicyResourceLockFeatureAPI extends OrderedService {
     }
 
     /**
-     * This method is called before a lock is acquired on a resource.  It may be
-     * invoked repeatedly to extend the time that a lock is held.
+     * This method is called before a lock is acquired on a resource.
      * 
      * @param resourceId
      * @param owner
diff --git a/policy-core/src/main/java/org/onap/policy/drools/core/lock/SimpleLockManager.java b/policy-core/src/main/java/org/onap/policy/drools/core/lock/SimpleLockManager.java
index 081ad4c1..243ba3cb 100644
--- a/policy-core/src/main/java/org/onap/policy/drools/core/lock/SimpleLockManager.java
+++ b/policy-core/src/main/java/org/onap/policy/drools/core/lock/SimpleLockManager.java
@@ -74,7 +74,9 @@ public class SimpleLockManager {
     }
 
     /**
-     * Attempts to lock a resource, extending the lock if the owner already holds it.
+     * Attempts to lock a resource, rejecting the lock if it is already owned, even if
+     * it's the same owner; the same owner can use {@link #refresh(String, String, int)
+     * refresh()}, instead, to extend a lock on a resource.
      * 
      * @param resourceId
      * @param owner
@@ -93,25 +95,19 @@ public class SimpleLockManager {
             throw makeNullArgException(MSG_NULL_OWNER);
         }
 
-        Data existingLock;
+        boolean locked = false;
         
         synchronized(locker) {
             cleanUpLocks();
 
-            if ((existingLock = resource2data.get(resourceId)) != null && existingLock.getOwner().equals(owner)) {
-                // replace the existing lock with an extended lock
-                locks.remove(existingLock);
-                existingLock = null;
-            }
-
-            if (existingLock == null) {
+            if(!resource2data.containsKey(resourceId)) {
                 Data data = new Data(owner, resourceId, currentTime.getMillis() + TimeUnit.SECONDS.toMillis(holdSec));
                 resource2data.put(resourceId, data);
                 locks.add(data);
+                locked = true;
             }
         }
 
-        boolean locked = (existingLock == null);
         logger.info("lock {} for resource {} owner {}", locked, resourceId, owner);
 
         return locked;