Use request id instead of PDP name in listener

Modified the listener that receives messages from the PDPs
to use the request id instead of the PDP name for tracking
purposes.

Modified the listener to make it more generic so any arbitrary ID
can be used, depending on the context.

Combined extractId into handleEvent.

Corrected a comment.

Change-Id: I6b7097c67d73f51b78ae4063341bcb118eb14bbc
Issue-ID: POLICY-1542
Signed-off-by: Jim Hahn <jrh3@att.com>

2 files changed, 127 insertions, 50 deletions

diff --git a/main/src/main/java/org/onap/policy/pap/main/comm/MultiPdpStatusListener.java b/main/src/main/java/org/onap/policy/pap/main/comm/MultiPdpStatusListener.java
index 38588d89..652756a4 100644
--- a/main/src/main/java/org/onap/policy/pap/main/comm/MultiPdpStatusListener.java
+++ b/main/src/main/java/org/onap/policy/pap/main/comm/MultiPdpStatusListener.java
@@ -30,12 +30,15 @@ import java.util.concurrent.TimeUnit;
 import org.onap.policy.common.endpoints.event.comm.Topic.CommInfrastructure;
 import org.onap.policy.common.endpoints.listeners.TypedMessageListener;
 import org.onap.policy.pdp.common.models.PdpStatus;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
  * Listener for PDP Status messages expected to be received from multiple PDPs. The
  * listener "completes" once a message has been seen from all of the PDPs.
  */
-public class MultiPdpStatusListener implements TypedMessageListener<PdpStatus> {
+public abstract class MultiPdpStatusListener implements TypedMessageListener<PdpStatus> {
+    private static final Logger logger = LoggerFactory.getLogger(MultiPdpStatusListener.class);
 
     /**
      * This is decremented once a message has been received from every PDP.
@@ -43,40 +46,40 @@ public class MultiPdpStatusListener implements TypedMessageListener<PdpStatus> {
     private final CountDownLatch allSeen = new CountDownLatch(1);
 
     /**
-     * PDPs from which no message has been received yet.
+     * IDs for which no message has been received yet.
      */
-    private final Set<String> unseenPdpNames = ConcurrentHashMap.newKeySet();
+    private final Set<String> unseenIds = ConcurrentHashMap.newKeySet();
 
     /**
      * Constructs the object.
      *
-     * @param pdpName name of the PDP for which to wait
+     * @param id ID for which to wait
      */
-    public MultiPdpStatusListener(String pdpName) {
-        unseenPdpNames.add(pdpName);
+    public MultiPdpStatusListener(String id) {
+        unseenIds.add(id);
     }
 
     /**
      * Constructs the object.
      *
-     * @param pdpNames names of the PDP for which to wait
+     * @param ids IDs for which to wait
      */
-    public MultiPdpStatusListener(Collection<String> pdpNames) {
-        if (pdpNames.isEmpty()) {
+    public MultiPdpStatusListener(Collection<String> ids) {
+        if (ids.isEmpty()) {
             allSeen.countDown();
 
         } else {
-            unseenPdpNames.addAll(pdpNames);
+            unseenIds.addAll(ids);
         }
     }
 
     /**
-     * Gets the set of names for which messages have not yet been received.
+     * Gets the set of IDs for which messages have not yet been received.
      *
-     * @return the names of the PDPs that have not been seen yet
+     * @return the IDs that have not been seen yet
      */
-    public SortedSet<String> getUnseenPdpNames() {
-        return new TreeSet<>(unseenPdpNames);
+    public SortedSet<String> getUnseenIds() {
+        return new TreeSet<>(unseenIds);
     }
 
     /**
@@ -93,17 +96,37 @@ public class MultiPdpStatusListener implements TypedMessageListener<PdpStatus> {
     }
 
     /**
-     * Indicates that a message was received for a PDP. Triggers completion of
-     * {@link #await(long, TimeUnit)} if all PDPs have received a message. Threads may
-     * override this method to process a message. However, they should still invoke this
-     * method so that PDPs can be properly tracked.
+     * After giving the event to the subclass via
+     * {@link #handleEvent(CommInfrastructure, String, PdpStatus)}, this triggers
+     * completion of {@link #await(long, TimeUnit)}, if all PDPs have received a message.
      */
     @Override
-    public void onTopicEvent(CommInfrastructure infra, String topic, PdpStatus message) {
-        unseenPdpNames.remove(message.getName());
+    public final void onTopicEvent(CommInfrastructure infra, String topic, PdpStatus message) {
+        String id = null;
+        try {
+            id = handleEvent(infra, topic, message);
+        } catch (RuntimeException e) {
+            logger.warn("handleEvent failed due to: {}", e.getMessage(), e);
+        }
+
+        if (id == null) {
+            return;
+        }
+
+        unseenIds.remove(id);
 
-        if (unseenPdpNames.isEmpty()) {
+        if (unseenIds.isEmpty()) {
             allSeen.countDown();
         }
     }
+
+    /**
+     * Indicates that a message was received for a PDP.
+     *
+     * @param infra infrastructure with which the message was received
+     * @param topic topic on which the message was received
+     * @param message message that was received
+     * @return the ID extracted from the message, or {@code null} if it cannot be extracted
+     */
+    protected abstract String handleEvent(CommInfrastructure infra, String topic, PdpStatus message);
 }
diff --git a/main/src/test/java/org/onap/policy/pap/main/comm/MultiPdpStatusListenerTest.java b/main/src/test/java/org/onap/policy/pap/main/comm/MultiPdpStatusListenerTest.java
index 2dc1aa2c..d0dba808 100644
--- a/main/src/test/java/org/onap/policy/pap/main/comm/MultiPdpStatusListenerTest.java
+++ b/main/src/test/java/org/onap/policy/pap/main/comm/MultiPdpStatusListenerTest.java
@@ -32,78 +32,79 @@ import java.util.concurrent.atomic.AtomicBoolean;
 import org.junit.Test;
 import org.onap.policy.common.endpoints.event.comm.Topic.CommInfrastructure;
 import org.onap.policy.pap.main.comm.MultiPdpStatusListener;
+import org.onap.policy.pdp.common.models.PdpResponseDetails;
 import org.onap.policy.pdp.common.models.PdpStatus;
 
 public class MultiPdpStatusListenerTest {
     private static final CommInfrastructure INFRA = CommInfrastructure.NOOP;
     private static final String TOPIC = "my-topic";
-    private static final String NAME1 = "pdp_1";
-    private static final String NAME2 = "pdp_2";
-    private static final List<String> NAME_LIST = Arrays.asList(NAME1, NAME2);
+    private static final String ID1 = "request-1";
+    private static final String ID2 = "request-2";
+    private static final List<String> ID_LIST = Arrays.asList(ID1, ID2);
 
     private MultiPdpStatusListener listener;
     private PdpStatus status;
 
     @Test
     public void testMultiPdpStatusListenerString() throws Exception {
-        listener = new MultiPdpStatusListener(NAME1);
-        assertEquals(Arrays.asList(NAME1).toString(), listener.getUnseenPdpNames().toString());
+        listener = new MyListener(ID1);
+        assertEquals(Arrays.asList(ID1).toString(), listener.getUnseenIds().toString());
 
-        // a name is in the queue - not done yet
+        // an ID is in the queue - not done yet
         assertFalse(doWait(0));
     }
 
     @Test
     public void testMultiPdpStatusListenerCollectionOfString() throws Exception {
-        List<String> lst = NAME_LIST;
+        List<String> lst = ID_LIST;
 
-        listener = new MultiPdpStatusListener(lst);
-        assertEquals(lst.toString(), listener.getUnseenPdpNames().toString());
+        listener = new MyListener(lst);
+        assertEquals(lst.toString(), listener.getUnseenIds().toString());
 
-        // a name is in the queue - not done yet
+        // an ID is in the queue - not done yet
         assertFalse(doWait(0));
 
         /*
          * Try with an empty list - should already be complete.
          */
-        listener = new MultiPdpStatusListener(new LinkedList<>());
-        assertTrue(listener.getUnseenPdpNames().isEmpty());
+        listener = new MyListener(new LinkedList<>());
+        assertTrue(listener.getUnseenIds().isEmpty());
         assertTrue(doWait(0));
     }
 
     @Test
-    public void testGetUnseenPdpNames() {
-        List<String> lst = NAME_LIST;
+    public void testGetUnseenIds() {
+        List<String> lst = ID_LIST;
 
-        listener = new MultiPdpStatusListener(lst);
-        assertEquals(lst.toString(), listener.getUnseenPdpNames().toString());
+        listener = new MyListener(lst);
+        assertEquals(lst.toString(), listener.getUnseenIds().toString());
 
         // receive message from one PDP
         status = new PdpStatus();
-        status.setName(NAME2);
+        status.setResponse(makeResponse(ID2));
         listener.onTopicEvent(INFRA, TOPIC, status);
-        assertEquals(Arrays.asList(NAME1).toString(), listener.getUnseenPdpNames().toString());
+        assertEquals(Arrays.asList(ID1).toString(), listener.getUnseenIds().toString());
 
         // receive message from the other PDP
         status = new PdpStatus();
-        status.setName(NAME1);
+        status.setResponse(makeResponse(ID1));
         listener.onTopicEvent(INFRA, TOPIC, status);
-        assertTrue(listener.getUnseenPdpNames().isEmpty());
+        assertTrue(listener.getUnseenIds().isEmpty());
     }
 
     @Test
     public void testAwait() throws Exception {
         // try with an empty list - should already be complete
-        listener = new MultiPdpStatusListener(new LinkedList<>());
+        listener = new MyListener(new LinkedList<>());
         assertTrue(doWait(0));
 
         // try it with something in the list
-        listener = new MultiPdpStatusListener(NAME_LIST);
+        listener = new MyListener(ID_LIST);
         assertFalse(doWait(0));
 
         // process a message from one PDP - wait should block the entire time
         status = new PdpStatus();
-        status.setName(NAME1);
+        status.setResponse(makeResponse(ID1));
         listener.onTopicEvent(INFRA, TOPIC, status);
         long tbeg = System.currentTimeMillis();
         assertFalse(doWait(50));
@@ -111,7 +112,7 @@ public class MultiPdpStatusListenerTest {
 
         // process a message from the other PDP - wait should NOT block
         status = new PdpStatus();
-        status.setName(NAME2);
+        status.setResponse(makeResponse(ID2));
         listener.onTopicEvent(INFRA, TOPIC, status);
         tbeg = System.currentTimeMillis();
         assertTrue(doWait(4000));
@@ -120,28 +121,52 @@ public class MultiPdpStatusListenerTest {
 
     @Test
     public void testOnTopicEvent() throws Exception {
-        listener = new MultiPdpStatusListener(NAME_LIST);
+        listener = new MyListener(ID_LIST);
 
         // not done yet
         assertFalse(doWait(0));
 
-        // process a message - still not done as have another name to go
+        // process a message - still not done as have another ID to go
         status = new PdpStatus();
-        status.setName(NAME1);
+        status.setResponse(makeResponse(ID1));
         listener.onTopicEvent(INFRA, TOPIC, status);
         assertFalse(doWait(0));
 
         // process a message from the same PDP - still not done
         status = new PdpStatus();
-        status.setName(NAME1);
+        status.setResponse(makeResponse(ID1));
         listener.onTopicEvent(INFRA, TOPIC, status);
         assertFalse(doWait(0));
 
         // process another message - now we're done
         status = new PdpStatus();
-        status.setName(NAME2);
+        status.setResponse(makeResponse(ID2));
         listener.onTopicEvent(INFRA, TOPIC, status);
         assertTrue(doWait(0));
+
+        // handleEvent throws an exception - doWait does not return true
+        listener = new MyListener(ID1) {
+            @Override
+            protected String handleEvent(CommInfrastructure infra, String topic, PdpStatus message) {
+                throw new RuntimeException("expected exception");
+            }
+        };
+        status = new PdpStatus();
+        status.setResponse(makeResponse(ID1));
+        listener.onTopicEvent(INFRA, TOPIC, status);
+        assertFalse(doWait(0));
+
+        // handleEvent returns null - doWait does not return true
+        listener = new MyListener(ID1) {
+            @Override
+            protected String handleEvent(CommInfrastructure infra, String topic, PdpStatus message) {
+                return null;
+            }
+        };
+        status = new PdpStatus();
+        status.setResponse(makeResponse(ID1));
+        listener.onTopicEvent(INFRA, TOPIC, status);
+        assertFalse(doWait(0));
     }
 
     /**
@@ -174,4 +199,33 @@ public class MultiPdpStatusListenerTest {
 
         return done.get();
     }
+
+    /**
+     * Makes a response for the given request ID.
+     *
+     * @param id ID of the request
+     * @return a new response
+     */
+    private PdpResponseDetails makeResponse(String id) {
+        PdpResponseDetails resp = new PdpResponseDetails();
+        resp.setResponseTo(id);
+
+        return resp;
+    }
+
+    private static class MyListener extends MultiPdpStatusListener {
+
+        public MyListener(String id) {
+            super(id);
+        }
+
+        public MyListener(List<String> lst) {
+            super(lst);
+        }
+
+        @Override
+        protected String handleEvent(CommInfrastructure infra, String topic, PdpStatus message) {
+            return (message.getResponse().getResponseTo());
+        }
+    }
 }