Invoke lock callback in session thread

Injects the callback as a DroolsRunnable into the session, if
there is one.  Otherwise, it invokes it via the engine's
thread pool.

Issue-ID: POLICY-2246
Signed-off-by: Jim Hahn <jrh3@att.com>
Change-Id: I214480ae675d89e7335dde4eb4abe2684f7ef8ab
Signed-off-by: Jim Hahn <jrh3@att.com>

6 files changed, 134 insertions, 79 deletions

diff --git a/policy-management/src/main/java/org/onap/policy/drools/system/internal/FeatureLockImpl.java b/policy-management/src/main/java/org/onap/policy/drools/system/internal/FeatureLockImpl.java
index d4e4f5fc..5690b187 100644
--- a/policy-management/src/main/java/org/onap/policy/drools/system/internal/FeatureLockImpl.java
+++ b/policy-management/src/main/java/org/onap/policy/drools/system/internal/FeatureLockImpl.java
@@ -21,6 +21,8 @@
 package org.onap.policy.drools.system.internal;
 
 import java.util.concurrent.ScheduledExecutorService;
+import org.onap.policy.drools.core.DroolsRunnable;
+import org.onap.policy.drools.core.PolicySession;
 import org.onap.policy.drools.core.lock.LockCallback;
 import org.onap.policy.drools.core.lock.LockImpl;
 import org.onap.policy.drools.core.lock.LockState;
@@ -66,13 +68,9 @@ public abstract class FeatureLockImpl extends LockImpl {
     }
 
     /**
-     * Grants this lock. The notification is <i>always</i> invoked via a background
-     * thread.
-     *
-     * @param foreground {@code true} if to invoke the callback in the foreground thread,
-     *        {@code false} otherwise
+     * Grants this lock.
      */
-    protected synchronized void grant(boolean foreground) {
+    protected synchronized void grant() {
         if (isUnavailable()) {
             return;
         }
@@ -81,32 +79,37 @@ public abstract class FeatureLockImpl extends LockImpl {
         updateGrant();
 
         logger.info("lock granted: {}", this);
-
-        if (foreground) {
-            notifyAvailable();
-        } else {
-            getThreadPool().execute(this::notifyAvailable);
-        }
+        doNotify(this::notifyAvailable);
     }
 
     /**
      * Permanently denies this lock.
      *
      * @param reason the reason the lock was denied
-     * @param foreground {@code true} if to invoke the callback in the foreground thread,
-     *        {@code false} otherwise
      */
-    public void deny(String reason, boolean foreground) {
+    public void deny(String reason) {
         synchronized (this) {
             setState(LockState.UNAVAILABLE);
         }
 
         logger.info("{}: {}", reason, this);
+        doNotify(this::notifyUnavailable);
+    }
+
+    /**
+     * Notifies the session of a change in the lock state. If a session is attached, then
+     * it simply injects the notifier into the session. Otherwise, it executes it via a
+     * background thread.
+     *
+     * @param notifier function to invoke the callback
+     */
+    private void doNotify(DroolsRunnable notifier) {
+        PolicySession sess = getSession();
+        if (sess != null) {
+            sess.insertDrools(notifier);
 
-        if (foreground) {
-            notifyUnavailable();
         } else {
-            getThreadPool().execute(this::notifyUnavailable);
+            getThreadPool().execute(notifier);
         }
     }
 
@@ -164,7 +167,7 @@ public abstract class FeatureLockImpl extends LockImpl {
 
         // do a quick check of the state
         if (isUnavailable() || !attachFeature()) {
-            deny(LOCK_LOST_MSG, true);
+            deny(LOCK_LOST_MSG);
             return false;
         }
 
@@ -200,12 +203,13 @@ public abstract class FeatureLockImpl extends LockImpl {
      */
     protected abstract boolean addToFeature();
 
-    /**
-     * Gets the thread pool.
-     *
-     * @return the thread pool
-     */
+    // these may be overridden by junit tests
+
     protected ScheduledExecutorService getThreadPool() {
         return PolicyEngineConstants.getManager().getExecutorService();
     }
+
+    protected PolicySession getSession() {
+        return PolicySession.getCurrentSession();
+    }
 }
diff --git a/policy-management/src/main/java/org/onap/policy/drools/system/internal/LockManager.java b/policy-management/src/main/java/org/onap/policy/drools/system/internal/LockManager.java
index 7e4505be..ef6b48d2 100644
--- a/policy-management/src/main/java/org/onap/policy/drools/system/internal/LockManager.java
+++ b/policy-management/src/main/java/org/onap/policy/drools/system/internal/LockManager.java
@@ -156,7 +156,7 @@ public abstract class LockManager<T extends FeatureLockImpl> implements PolicyRe
             logger.debug("added lock to map {}", lock);
             finishLock(lock);
         } else {
-            lock.deny("resource is busy", true);
+            lock.deny("resource is busy");
         }
 
         return lock;
diff --git a/policy-management/src/main/java/org/onap/policy/drools/system/internal/SimpleLockManager.java b/policy-management/src/main/java/org/onap/policy/drools/system/internal/SimpleLockManager.java
index 839c17dc..a62d7667 100644
--- a/policy-management/src/main/java/org/onap/policy/drools/system/internal/SimpleLockManager.java
+++ b/policy-management/src/main/java/org/onap/policy/drools/system/internal/SimpleLockManager.java
@@ -158,14 +158,14 @@ public class SimpleLockManager extends LockManager<SimpleLockManager.SimpleLock>
 
             SimpleLock lock = lockref.get();
             if (lock != null) {
-                lock.deny("lock expired", false);
+                lock.deny("lock expired");
             }
         }
     }
 
     @Override
     protected void finishLock(SimpleLock lock) {
-        lock.grant(true);
+        lock.grant();
     }
 
     @Override
@@ -257,9 +257,9 @@ public class SimpleLockManager extends LockManager<SimpleLockManager.SimpleLock>
             }
 
             if (resource2lock.get(getResourceId()) == this) {
-                grant(true);
+                grant();
             } else {
-                deny(NOT_LOCKED_MSG, true);
+                deny(NOT_LOCKED_MSG);
             }
         }
 
diff --git a/policy-management/src/test/java/org/onap/policy/drools/system/internal/FeatureLockImplTest.java b/policy-management/src/test/java/org/onap/policy/drools/system/internal/FeatureLockImplTest.java
index 258ee0c5..a224a636 100644
--- a/policy-management/src/test/java/org/onap/policy/drools/system/internal/FeatureLockImplTest.java
+++ b/policy-management/src/test/java/org/onap/policy/drools/system/internal/FeatureLockImplTest.java
@@ -46,6 +46,8 @@ import org.junit.Test;
 import org.mockito.ArgumentCaptor;
 import org.mockito.Mock;
 import org.mockito.MockitoAnnotations;
+import org.onap.policy.drools.core.DroolsRunnable;
+import org.onap.policy.drools.core.PolicySession;
 import org.onap.policy.drools.core.lock.LockCallback;
 import org.onap.policy.drools.core.lock.LockState;
 import org.onap.policy.drools.system.PolicyEngineConstants;
@@ -126,30 +128,10 @@ public class FeatureLockImplTest {
         assertEquals(HOLD_SEC, lock.getHoldSec());
     }
 
-    /**
-     * Tests grant(), when using the foreground thread.
-     */
-    @Test
-    public void testGrantForeground() {
-        MyLock lock = new MyLock(LockState.WAITING, RESOURCE, OWNER_KEY, HOLD_SEC, callback);
-        lock.grant(true);
-
-        assertTrue(lock.isActive());
-        assertEquals(1, lock.nupdates);
-
-        verify(exsvc, never()).execute(any());
-
-        verify(callback).lockAvailable(any());
-        verify(callback, never()).lockUnavailable(any());
-    }
-
-    /**
-     * Tests grant(), when using the background thread.
-     */
     @Test
-    public void testGrantBackground() {
+    public void testGrant() {
         MyLock lock = new MyLock(LockState.WAITING, RESOURCE, OWNER_KEY, HOLD_SEC, callback);
-        lock.grant(false);
+        lock.grant();
 
         assertTrue(lock.isActive());
         assertEquals(1, lock.nupdates);
@@ -166,7 +148,7 @@ public class FeatureLockImplTest {
     public void testGrantUnavailable() {
         MyLock lock = new MyLock(LockState.UNAVAILABLE, RESOURCE, OWNER_KEY, HOLD_SEC, callback);
         lock.setState(LockState.UNAVAILABLE);
-        lock.grant(true);
+        lock.grant();
 
         assertTrue(lock.isUnavailable());
         assertEquals(0, lock.nupdates);
@@ -174,35 +156,65 @@ public class FeatureLockImplTest {
         verify(exsvc, never()).execute(any());
     }
 
-    /**
-     * Tests deny(), when using the foreground thread.
-     */
     @Test
-    public void testDenyForeground() {
+    public void testDeny() {
         MyLock lock = new MyLock(LockState.WAITING, RESOURCE, OWNER_KEY, HOLD_SEC, callback);
-        lock.deny("my reason", true);
+        lock.deny("my reason");
 
         assertTrue(lock.isUnavailable());
 
-        verify(exsvc, never()).execute(any());
-
+        invokeCallback(1);
         verify(callback, never()).lockAvailable(any());
         verify(callback).lockUnavailable(any());
     }
 
     /**
-     * Tests deny(), when using the background thread.
+     * Tests doNotify() when a session exists.
      */
     @Test
-    public void testDenyBackground() {
+    public void testDoNotifySession() {
+        PolicySession session = mock(PolicySession.class);
+
+        MyLock lock = new MyLock(LockState.WAITING, RESOURCE, OWNER_KEY, HOLD_SEC, callback) {
+            private static final long serialVersionUID = 1L;
+
+            @Override
+            protected PolicySession getSession() {
+                return session;
+            }
+        };
+
+        lock.grant();
+
+        assertTrue(lock.isActive());
+        assertEquals(1, lock.nupdates);
+
+        verify(exsvc, never()).execute(any());
+
+        ArgumentCaptor<Object> captor = ArgumentCaptor.forClass(Object.class);
+        verify(session).insertDrools(captor.capture());
+
+        DroolsRunnable runner = (DroolsRunnable) captor.getValue();
+        runner.run();
+
+        verify(callback).lockAvailable(any());
+        verify(callback, never()).lockUnavailable(any());
+    }
+
+    /**
+     * Tests doNotify() when there is no session.
+     */
+    @Test
+    public void testDoNotifyNoSession() {
         MyLock lock = new MyLock(LockState.WAITING, RESOURCE, OWNER_KEY, HOLD_SEC, callback);
-        lock.deny("my reason", false);
+        lock.grant();
 
-        assertTrue(lock.isUnavailable());
+        assertTrue(lock.isActive());
+        assertEquals(1, lock.nupdates);
 
         invokeCallback(1);
-        verify(callback, never()).lockAvailable(any());
-        verify(callback).lockUnavailable(any());
+        verify(callback).lockAvailable(any());
+        verify(callback, never()).lockUnavailable(any());
     }
 
     @Test
@@ -283,6 +295,7 @@ public class FeatureLockImplTest {
         assertEquals(HOLD_SEC2, lock.getHoldSec());
         assertSame(scallback, lock.getCallback());
 
+        invokeCallback(1);
         verify(scallback, never()).lockAvailable(lock);
         verify(scallback).lockUnavailable(lock);
     }
@@ -324,11 +337,20 @@ public class FeatureLockImplTest {
         assertEquals(HOLD_SEC2, lock.getHoldSec());
         assertSame(scallback, lock.getCallback());
 
+        invokeCallback(1);
         verify(scallback, never()).lockAvailable(lock);
         verify(scallback).lockUnavailable(lock);
     }
 
     @Test
+    public void testGetSession() {
+        MyLockStdSession lock = new MyLockStdSession(LockState.WAITING, RESOURCE, OWNER_KEY, HOLD_SEC, callback);
+
+        // this should invoke the real policy session without throwing an exception
+        lock.grant();
+    }
+
+    @Test
     public void testToString() {
         String text = new MyLock(LockState.WAITING, RESOURCE, OWNER_KEY, HOLD_SEC, callback).toString();
         assertNotNull(text);
@@ -361,15 +383,19 @@ public class FeatureLockImplTest {
         }
     }
 
-    public static class MyLock extends FeatureLockImpl {
+    /**
+     * Lock that inherits the normal getSession() method.
+     */
+    public static class MyLockStdSession extends FeatureLockImpl {
         private static final long serialVersionUID = 1L;
-        private int nupdates = 0;
+        protected int nupdates = 0;
 
-        public MyLock() {
+        public MyLockStdSession() {
             super();
         }
 
-        public MyLock(LockState state, String resourceId, String ownerKey, int holdSec, LockCallback callback) {
+        public MyLockStdSession(LockState state, String resourceId, String ownerKey, int holdSec,
+                        LockCallback callback) {
             super(state, resourceId, ownerKey, holdSec, callback);
         }
 
@@ -395,6 +421,23 @@ public class FeatureLockImplTest {
         }
     }
 
+    public static class MyLock extends MyLockStdSession {
+        private static final long serialVersionUID = 1L;
+
+        public MyLock() {
+            super();
+        }
+
+        public MyLock(LockState state, String resourceId, String ownerKey, int holdSec, LockCallback callback) {
+            super(state, resourceId, ownerKey, holdSec, callback);
+        }
+
+        @Override
+        protected PolicySession getSession() {
+            return null;
+        }
+    }
+
     public static class MyLockNoFeature extends MyLock {
         private static final long serialVersionUID = 1L;
 
diff --git a/policy-management/src/test/java/org/onap/policy/drools/system/internal/LockManagerTest.java b/policy-management/src/test/java/org/onap/policy/drools/system/internal/LockManagerTest.java
index 1cda079d..6b6e7363 100644
--- a/policy-management/src/test/java/org/onap/policy/drools/system/internal/LockManagerTest.java
+++ b/policy-management/src/test/java/org/onap/policy/drools/system/internal/LockManagerTest.java
@@ -208,7 +208,7 @@ public class LockManagerTest {
 
         @Override
         protected void finishLock(MyLock lock) {
-            lock.grant(true);
+            lock.grant();
         }
 
         @Override
diff --git a/policy-management/src/test/java/org/onap/policy/drools/system/internal/SimpleLockManagerTest.java b/policy-management/src/test/java/org/onap/policy/drools/system/internal/SimpleLockManagerTest.java
index 79e20673..b1c34c24 100644
--- a/policy-management/src/test/java/org/onap/policy/drools/system/internal/SimpleLockManagerTest.java
+++ b/policy-management/src/test/java/org/onap/policy/drools/system/internal/SimpleLockManagerTest.java
@@ -55,11 +55,13 @@ import org.junit.AfterClass;
 import org.junit.Before;
 import org.junit.BeforeClass;
 import org.junit.Test;
+import org.kie.api.runtime.KieSession;
 import org.mockito.ArgumentCaptor;
 import org.mockito.Mock;
 import org.mockito.MockitoAnnotations;
 import org.onap.policy.common.utils.time.CurrentTime;
 import org.onap.policy.common.utils.time.TestTime;
+import org.onap.policy.drools.core.PolicySession;
 import org.onap.policy.drools.core.lock.Lock;
 import org.onap.policy.drools.core.lock.LockCallback;
 import org.onap.policy.drools.core.lock.LockState;
@@ -85,12 +87,16 @@ public class SimpleLockManagerTest {
     private static ScheduledExecutorService saveExec;
     private static ScheduledExecutorService realExec;
 
+    private PolicySession session;
     private TestTime testTime;
     private AtomicInteger nactive;
     private AtomicInteger nsuccesses;
     private SimpleLockManager feature;
 
     @Mock
+    private KieSession kieSess;
+
+    @Mock
     private ScheduledExecutorService exsvc;
 
     @Mock
@@ -130,6 +136,16 @@ public class SimpleLockManagerTest {
     public void setUp() {
         MockitoAnnotations.initMocks(this);
 
+        // grant() and deny() calls will come through here and be immediately executed
+        session = new PolicySession(null, null, kieSess) {
+            @Override
+            public void insertDrools(Object object) {
+                ((Runnable) object).run();
+            }
+        };
+
+        session.setPolicySession();
+
         testTime = new TestTime();
         nactive = new AtomicInteger(0);
         nsuccesses = new AtomicInteger(0);
@@ -252,10 +268,6 @@ public class SimpleLockManagerTest {
         assertFalse(lock2.isActive());
         assertTrue(lock3.isActive());
 
-        // run the callbacks
-        captor = ArgumentCaptor.forClass(Runnable.class);
-        verify(exsvc, times(2)).execute(captor.capture());
-        captor.getAllValues().forEach(Runnable::run);
         verify(callback).lockUnavailable(lock);
         verify(callback).lockUnavailable(lock2);
         verify(callback, never()).lockUnavailable(lock3);
@@ -272,10 +284,6 @@ public class SimpleLockManagerTest {
         checker.run();
         assertFalse(lock3.isActive());
 
-        // run the callback
-        captor = ArgumentCaptor.forClass(Runnable.class);
-        verify(exsvc, times(3)).execute(captor.capture());
-        captor.getValue().run();
         verify(callback).lockUnavailable(lock3);
     }
 
@@ -433,7 +441,7 @@ public class SimpleLockManagerTest {
     @Test
     public void testSimpleLockExpired() {
         SimpleLock lock = getLock(RESOURCE, OWNER_KEY, HOLD_SEC, callback, false);
-        lock.grant(true);
+        lock.grant();
 
         assertFalse(lock.expired(testTime.getMillis()));
         assertFalse(lock.expired(testTime.getMillis() + HOLD_MS - 1));