Generate notifications when policies change

Updated existing PAP code to make use of new notification classes.

Change-Id: I4637ad92ac4f432f215cfc837e672c75074d88b5
Issue-ID: POLICY-1841
Signed-off-by: Jim Hahn <jrh3@att.com>

14 files changed, 292 insertions, 49 deletions

diff --git a/main/src/main/java/org/onap/policy/pap/main/PapConstants.java b/main/src/main/java/org/onap/policy/pap/main/PapConstants.java
index 3fc36f35..b8b199e6 100644
--- a/main/src/main/java/org/onap/policy/pap/main/PapConstants.java
+++ b/main/src/main/java/org/onap/policy/pap/main/PapConstants.java
@@ -31,10 +31,12 @@ public class PapConstants {
     public static final String REG_PDP_MODIFY_LOCK = "lock:pdp";
     public static final String REG_PDP_MODIFY_MAP = "object:pdp/modify/map";
     public static final String REG_PDP_TRACKER = "object:pdp/tracker";
+    public static final String REG_POLICY_NOTIFIER = "object:policy/notifier";
     public static final String REG_PAP_DAO_FACTORY = "object:pap/dao/factory";
 
     // topic names
     public static final String TOPIC_POLICY_PDP_PAP = "POLICY-PDP-PAP";
+    public static final String TOPIC_POLICY_NOTIFICATION = "POLICY-NOTIFICATION";
 
     private PapConstants() {
         super();
diff --git a/main/src/main/java/org/onap/policy/pap/main/comm/PdpModifyRequestMap.java b/main/src/main/java/org/onap/policy/pap/main/comm/PdpModifyRequestMap.java
index 3f0b5c11..f058da32 100644
--- a/main/src/main/java/org/onap/policy/pap/main/comm/PdpModifyRequestMap.java
+++ b/main/src/main/java/org/onap/policy/pap/main/comm/PdpModifyRequestMap.java
@@ -41,6 +41,7 @@ import org.onap.policy.pap.main.comm.msgdata.Request;
 import org.onap.policy.pap.main.comm.msgdata.RequestListener;
 import org.onap.policy.pap.main.comm.msgdata.StateChangeReq;
 import org.onap.policy.pap.main.comm.msgdata.UpdateReq;
+import org.onap.policy.pap.main.notification.PolicyNotifier;
 import org.onap.policy.pap.main.parameters.PdpModifyRequestMapParams;
 import org.onap.policy.pap.main.parameters.RequestParams;
 import org.slf4j.Logger;
@@ -74,6 +75,11 @@ public class PdpModifyRequestMap {
      */
     private final PolicyModelsProviderFactoryWrapper daoFactory;
 
+    /**
+     * Used to notify when policy updates completes.
+     */
+    private final PolicyNotifier policyNotifier;
+
 
     /**
      * Constructs the object.
@@ -88,6 +94,7 @@ public class PdpModifyRequestMap {
         this.params = params;
         this.modifyLock = params.getModifyLock();
         this.daoFactory = params.getDaoFactory();
+        this.policyNotifier = params.getPolicyNotifier();
     }
 
     /**
@@ -150,7 +157,7 @@ public class PdpModifyRequestMap {
             .setMaxRetryCount(params.getParams().getUpdateParameters().getMaxRetryCount())
             .setTimers(params.getUpdateTimers())
             .setModifyLock(params.getModifyLock())
-            .setPublisher(params.getPublisher())
+            .setPdpPublisher(params.getPdpPublisher())
             .setResponseDispatcher(params.getResponseDispatcher());
         // @formatter:on
 
@@ -179,7 +186,7 @@ public class PdpModifyRequestMap {
             .setMaxRetryCount(params.getParams().getStateChangeParameters().getMaxRetryCount())
             .setTimers(params.getStateChangeTimers())
             .setModifyLock(params.getModifyLock())
-            .setPublisher(params.getPublisher())
+            .setPdpPublisher(params.getPdpPublisher())
             .setResponseDispatcher(params.getResponseDispatcher());
         // @formatter:on
 
@@ -299,7 +306,7 @@ public class PdpModifyRequestMap {
      * @return a new set of requests
      */
     protected PdpRequests makePdpRequests(String pdpName) {
-        return new PdpRequests(pdpName);
+        return new PdpRequests(pdpName, policyNotifier);
     }
 
     /**
@@ -359,6 +366,8 @@ public class PdpModifyRequestMap {
          */
         private void disablePdp(PdpRequests requests) {
 
+            policyNotifier.removePdp(requests.getPdpName());
+
             // remove the requests from the map
             if (!pdp2requests.remove(requests.getPdpName(), requests)) {
                 // don't have the info we need to disable it
diff --git a/main/src/main/java/org/onap/policy/pap/main/comm/PdpRequests.java b/main/src/main/java/org/onap/policy/pap/main/comm/PdpRequests.java
index 5863b2cb..4e1e9233 100644
--- a/main/src/main/java/org/onap/policy/pap/main/comm/PdpRequests.java
+++ b/main/src/main/java/org/onap/policy/pap/main/comm/PdpRequests.java
@@ -23,6 +23,7 @@ package org.onap.policy.pap.main.comm;
 import lombok.Getter;
 import org.onap.policy.models.pdp.concepts.PdpMessage;
 import org.onap.policy.pap.main.comm.msgdata.Request;
+import org.onap.policy.pap.main.notification.PolicyNotifier;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -45,6 +46,12 @@ public class PdpRequests {
     private final String pdpName;
 
     /**
+     * Notifier for policy update completions.
+     */
+    @Getter
+    private final PolicyNotifier notifier;
+
+    /**
      * Index of request currently being published.
      */
     private int curIndex = 0;
@@ -60,8 +67,9 @@ public class PdpRequests {
      *
      * @param pdpName name of the PDP with which the requests are associated
      */
-    public PdpRequests(String pdpName) {
+    public PdpRequests(String pdpName, PolicyNotifier notifier) {
         this.pdpName = pdpName;
+        this.notifier = notifier;
     }
 
     /**
@@ -71,6 +79,8 @@ public class PdpRequests {
      */
     public void addSingleton(Request request) {
 
+        request.setNotifier(notifier);
+
         if (request.getMessage().getName() == null) {
             throw new IllegalArgumentException("unexpected broadcast for " + pdpName);
         }
@@ -86,7 +96,7 @@ public class PdpRequests {
         singletons[priority] = request;
 
         // stop publishing anything of a lower priority
-        QueueToken<PdpMessage> token = stopPublishingLowerPriority(priority);
+        final QueueToken<PdpMessage> token = stopPublishingLowerPriority(priority);
 
         // start publishing if nothing of higher priority
         if (higherPrioritySingleton(priority)) {
diff --git a/main/src/main/java/org/onap/policy/pap/main/comm/msgdata/Request.java b/main/src/main/java/org/onap/policy/pap/main/comm/msgdata/Request.java
index 1f69dcb5..62aea789 100644
--- a/main/src/main/java/org/onap/policy/pap/main/comm/msgdata/Request.java
+++ b/main/src/main/java/org/onap/policy/pap/main/comm/msgdata/Request.java
@@ -23,6 +23,7 @@ package org.onap.policy.pap.main.comm.msgdata;
 import org.onap.policy.models.pdp.concepts.PdpMessage;
 import org.onap.policy.models.pdp.concepts.PdpStatus;
 import org.onap.policy.pap.main.comm.QueueToken;
+import org.onap.policy.pap.main.notification.PolicyNotifier;
 
 /**
  * Request data, whose message may be changed at any point, possibly triggering a restart
@@ -61,6 +62,13 @@ public interface Request {
     public void setListener(RequestListener listener);
 
     /**
+     * Sets the notifier to track responses to the request.
+     *
+     * @param notifier notifier used to publish notifications
+     */
+    public void setNotifier(PolicyNotifier notifier);
+
+    /**
      * Determines if this request is currently being published.
      *
      * @return {@code true} if this request is being published, {@code false} otherwise
diff --git a/main/src/main/java/org/onap/policy/pap/main/comm/msgdata/RequestImpl.java b/main/src/main/java/org/onap/policy/pap/main/comm/msgdata/RequestImpl.java
index 1945b32d..a110ef44 100644
--- a/main/src/main/java/org/onap/policy/pap/main/comm/msgdata/RequestImpl.java
+++ b/main/src/main/java/org/onap/policy/pap/main/comm/msgdata/RequestImpl.java
@@ -30,6 +30,7 @@ import org.onap.policy.models.pdp.concepts.PdpMessage;
 import org.onap.policy.models.pdp.concepts.PdpStatus;
 import org.onap.policy.pap.main.comm.QueueToken;
 import org.onap.policy.pap.main.comm.TimerManager;
+import org.onap.policy.pap.main.notification.PolicyNotifier;
 import org.onap.policy.pap.main.parameters.RequestParams;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -64,6 +65,13 @@ public abstract class RequestImpl implements Request {
     private RequestListener listener;
 
     /**
+     * Notifier for policy update completions.
+     */
+    @Getter
+    @Setter
+    private PolicyNotifier notifier;
+
+    /**
      * Current retry count.
      */
     @Getter
@@ -217,7 +225,7 @@ public abstract class RequestImpl implements Request {
 
         // couldn't take the other's place - add our own token to the queue
         token = new QueueToken<>(message);
-        params.getPublisher().enqueue(token);
+        params.getPdpPublisher().enqueue(token);
     }
 
     /**
diff --git a/main/src/main/java/org/onap/policy/pap/main/comm/msgdata/StateChangeReq.java b/main/src/main/java/org/onap/policy/pap/main/comm/msgdata/StateChangeReq.java
index e38cb0fd..40acd3ad 100644
--- a/main/src/main/java/org/onap/policy/pap/main/comm/msgdata/StateChangeReq.java
+++ b/main/src/main/java/org/onap/policy/pap/main/comm/msgdata/StateChangeReq.java
@@ -20,7 +20,6 @@
 
 package org.onap.policy.pap.main.comm.msgdata;
 
-import org.onap.policy.models.pdp.concepts.PdpMessage;
 import org.onap.policy.models.pdp.concepts.PdpStateChange;
 import org.onap.policy.models.pdp.concepts.PdpStatus;
 import org.onap.policy.pap.main.parameters.RequestParams;
@@ -39,7 +38,7 @@ public class StateChangeReq extends RequestImpl {
      *
      * @throws IllegalArgumentException if a required parameter is not set
      */
-    public StateChangeReq(RequestParams params, String name, PdpMessage message) {
+    public StateChangeReq(RequestParams params, String name, PdpStateChange message) {
         super(params, name, message);
     }
 
diff --git a/main/src/main/java/org/onap/policy/pap/main/comm/msgdata/UpdateReq.java b/main/src/main/java/org/onap/policy/pap/main/comm/msgdata/UpdateReq.java
index 8efdb7ca..6b04e726 100644
--- a/main/src/main/java/org/onap/policy/pap/main/comm/msgdata/UpdateReq.java
+++ b/main/src/main/java/org/onap/policy/pap/main/comm/msgdata/UpdateReq.java
@@ -26,7 +26,6 @@ import java.util.List;
 import java.util.Set;
 import java.util.stream.Collectors;
 import org.apache.commons.lang3.StringUtils;
-import org.onap.policy.models.pdp.concepts.PdpMessage;
 import org.onap.policy.models.pdp.concepts.PdpStatus;
 import org.onap.policy.models.pdp.concepts.PdpUpdate;
 import org.onap.policy.models.tosca.authorative.concepts.ToscaPolicy;
@@ -48,7 +47,7 @@ public class UpdateReq extends RequestImpl {
      *
      * @throws IllegalArgumentException if a required parameter is not set
      */
-    public UpdateReq(RequestParams params, String name, PdpMessage message) {
+    public UpdateReq(RequestParams params, String name, PdpUpdate message) {
         super(params, name, message);
     }
 
@@ -61,10 +60,15 @@ public class UpdateReq extends RequestImpl {
     public String checkResponse(PdpStatus response) {
         String reason = super.checkResponse(response);
         if (reason != null) {
+            // response isn't for this PDP - don't generate notifications
             return reason;
         }
 
+        Set<ToscaPolicyIdentifier> actualSet = new HashSet<>(alwaysList(response.getPolicies()));
+        getNotifier().processResponse(getName(), actualSet);
+
         PdpUpdate message = getMessage();
+
         if (!StringUtils.equals(message.getPdpGroup(), response.getPdpGroup())) {
             return "group does not match";
         }
@@ -74,11 +78,11 @@ public class UpdateReq extends RequestImpl {
         }
 
         // see if the policies match
-        Set<ToscaPolicyIdentifier> set1 = new HashSet<>(alwaysList(response.getPolicies()));
-        Set<ToscaPolicyIdentifier> set2 = new HashSet<>(alwaysList(message.getPolicies()).stream()
+
+        Set<ToscaPolicyIdentifier> expectedSet = new HashSet<>(alwaysList(message.getPolicies()).stream()
                         .map(ToscaPolicy::getIdentifier).collect(Collectors.toSet()));
 
-        if (!set1.equals(set2)) {
+        if (!actualSet.equals(expectedSet)) {
             return "policies do not match";
         }
 
diff --git a/main/src/main/java/org/onap/policy/pap/main/parameters/PdpModifyRequestMapParams.java b/main/src/main/java/org/onap/policy/pap/main/parameters/PdpModifyRequestMapParams.java
index 2f74bf3d..9a3e7a45 100644
--- a/main/src/main/java/org/onap/policy/pap/main/parameters/PdpModifyRequestMapParams.java
+++ b/main/src/main/java/org/onap/policy/pap/main/parameters/PdpModifyRequestMapParams.java
@@ -22,10 +22,12 @@ package org.onap.policy.pap.main.parameters;
 
 import lombok.Getter;
 import org.onap.policy.common.endpoints.listeners.RequestIdDispatcher;
+import org.onap.policy.models.pdp.concepts.PdpMessage;
 import org.onap.policy.models.pdp.concepts.PdpStatus;
 import org.onap.policy.pap.main.PolicyModelsProviderFactoryWrapper;
 import org.onap.policy.pap.main.comm.Publisher;
 import org.onap.policy.pap.main.comm.TimerManager;
+import org.onap.policy.pap.main.notification.PolicyNotifier;
 
 
 /**
@@ -33,13 +35,14 @@ import org.onap.policy.pap.main.comm.TimerManager;
  */
 @Getter
 public class PdpModifyRequestMapParams {
-    private Publisher publisher;
+    private Publisher<PdpMessage> pdpPublisher;
     private RequestIdDispatcher<PdpStatus> responseDispatcher;
     private Object modifyLock;
     private PdpParameters params;
     private TimerManager updateTimers;
     private TimerManager stateChangeTimers;
     private PolicyModelsProviderFactoryWrapper daoFactory;
+    private PolicyNotifier policyNotifier;
 
     public PdpModifyRequestMapParams setParams(PdpParameters params) {
         this.params = params;
@@ -61,8 +64,13 @@ public class PdpModifyRequestMapParams {
         return this;
     }
 
-    public PdpModifyRequestMapParams setPublisher(Publisher publisher) {
-        this.publisher = publisher;
+    public PdpModifyRequestMapParams setPolicyNotifier(PolicyNotifier policyNotifier) {
+        this.policyNotifier = policyNotifier;
+        return this;
+    }
+
+    public PdpModifyRequestMapParams setPdpPublisher(Publisher<PdpMessage> pdpPublisher) {
+        this.pdpPublisher = pdpPublisher;
         return this;
     }
 
@@ -80,7 +88,7 @@ public class PdpModifyRequestMapParams {
      * Validates the parameters.
      */
     public void validate() {
-        if (publisher == null) {
+        if (pdpPublisher == null) {
             throw new IllegalArgumentException("missing publisher");
         }
 
@@ -103,5 +111,13 @@ public class PdpModifyRequestMapParams {
         if (stateChangeTimers == null) {
             throw new IllegalArgumentException("missing stateChangeTimers");
         }
+
+        if (daoFactory == null) {
+            throw new IllegalArgumentException("missing DAO factory");
+        }
+
+        if (policyNotifier == null) {
+            throw new IllegalArgumentException("missing policy notifier");
+        }
     }
 }
diff --git a/main/src/main/java/org/onap/policy/pap/main/parameters/RequestParams.java b/main/src/main/java/org/onap/policy/pap/main/parameters/RequestParams.java
index b9083864..57d4ddaa 100644
--- a/main/src/main/java/org/onap/policy/pap/main/parameters/RequestParams.java
+++ b/main/src/main/java/org/onap/policy/pap/main/parameters/RequestParams.java
@@ -22,6 +22,7 @@ package org.onap.policy.pap.main.parameters;
 
 import lombok.Getter;
 import org.onap.policy.common.endpoints.listeners.RequestIdDispatcher;
+import org.onap.policy.models.pdp.concepts.PdpMessage;
 import org.onap.policy.models.pdp.concepts.PdpStatus;
 import org.onap.policy.pap.main.comm.Publisher;
 import org.onap.policy.pap.main.comm.TimerManager;
@@ -32,15 +33,15 @@ import org.onap.policy.pap.main.comm.TimerManager;
  */
 @Getter
 public class RequestParams {
-    private Publisher publisher;
+    private Publisher<PdpMessage> pdpPublisher;
     private RequestIdDispatcher<PdpStatus> responseDispatcher;
     private Object modifyLock;
     private TimerManager timers;
     private int maxRetryCount;
 
 
-    public RequestParams setPublisher(Publisher publisher) {
-        this.publisher = publisher;
+    public RequestParams setPdpPublisher(Publisher<PdpMessage> publisher) {
+        this.pdpPublisher = publisher;
         return this;
     }
 
@@ -68,7 +69,7 @@ public class RequestParams {
      * Validates the parameters.
      */
     public void validate() {
-        if (publisher == null) {
+        if (pdpPublisher == null) {
             throw new IllegalArgumentException("missing publisher");
         }
 
diff --git a/main/src/main/java/org/onap/policy/pap/main/rest/depundep/PdpGroupDeleteProvider.java b/main/src/main/java/org/onap/policy/pap/main/rest/depundep/PdpGroupDeleteProvider.java
index 0ca32451..09ad862b 100644
--- a/main/src/main/java/org/onap/policy/pap/main/rest/depundep/PdpGroupDeleteProvider.java
+++ b/main/src/main/java/org/onap/policy/pap/main/rest/depundep/PdpGroupDeleteProvider.java
@@ -21,12 +21,13 @@
 package org.onap.policy.pap.main.rest.depundep;
 
 import java.util.Iterator;
-import java.util.function.BiFunction;
+import java.util.Set;
 import java.util.function.Predicate;
+import java.util.stream.Collectors;
 import javax.ws.rs.core.Response.Status;
 import org.onap.policy.models.base.PfModelException;
+import org.onap.policy.models.pdp.concepts.Pdp;
 import org.onap.policy.models.pdp.concepts.PdpGroup;
-import org.onap.policy.models.pdp.concepts.PdpSubGroup;
 import org.onap.policy.models.pdp.enums.PdpState;
 import org.onap.policy.models.tosca.authorative.concepts.ToscaPolicy;
 import org.onap.policy.models.tosca.authorative.concepts.ToscaPolicyIdentifier;
@@ -122,7 +123,7 @@ public class PdpGroupDeleteProvider extends ProviderBase {
      * Returns a function that will remove the desired policy from a subgroup.
      */
     @Override
-    protected BiFunction<PdpGroup, PdpSubGroup, Boolean> makeUpdater(ToscaPolicy policy,
+    protected Updater makeUpdater(SessionData data, ToscaPolicy policy,
                     ToscaPolicyIdentifierOptVersion desiredIdent) {
 
         // construct a matcher based on whether or not the version was specified
@@ -142,6 +143,8 @@ public class PdpGroupDeleteProvider extends ProviderBase {
         // return a function that will remove the policy from the subgroup
         return (group, subgroup) -> {
 
+            Set<String> pdps = subgroup.getPdpInstances().stream().map(Pdp::getInstanceId).collect(Collectors.toSet());
+
             boolean result = false;
 
             Iterator<ToscaPolicyIdentifier> iter = subgroup.getPolicies().iterator();
@@ -153,6 +156,8 @@ public class PdpGroupDeleteProvider extends ProviderBase {
                     iter.remove();
                     logger.info("remove policy {} {} from subgroup {} {} count={}", ident.getName(), ident.getVersion(),
                                     group.getName(), subgroup.getPdpType(), subgroup.getPolicies().size());
+
+                    data.trackUndeploy(ident, pdps);
                 }
             }
 
diff --git a/main/src/main/java/org/onap/policy/pap/main/rest/depundep/PdpGroupDeployProvider.java b/main/src/main/java/org/onap/policy/pap/main/rest/depundep/PdpGroupDeployProvider.java
index bc3148ef..1e00528e 100644
--- a/main/src/main/java/org/onap/policy/pap/main/rest/depundep/PdpGroupDeployProvider.java
+++ b/main/src/main/java/org/onap/policy/pap/main/rest/depundep/PdpGroupDeployProvider.java
@@ -28,8 +28,8 @@ import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
-import java.util.function.BiFunction;
 import java.util.function.Consumer;
+import java.util.stream.Collectors;
 import javax.ws.rs.core.Response.Status;
 import org.onap.policy.common.parameters.BeanValidationResult;
 import org.onap.policy.common.parameters.ObjectValidationResult;
@@ -269,8 +269,9 @@ public class PdpGroupDeployProvider extends ProviderBase {
      * @param dbgroup the group, as it appears within the DB
      * @param group the group being updated
      * @return {@code true} if a subgroup was removed, {@code false} otherwise
+     * @throws PfModelException if an error occurred
      */
-    private boolean notifyPdpsDelSubGroups(SessionData data, PdpGroup dbgroup, PdpGroup group) {
+    private boolean notifyPdpsDelSubGroups(SessionData data, PdpGroup dbgroup, PdpGroup group) throws PfModelException {
         boolean updated = false;
 
         // subgroups, as they appear within the updated group
@@ -284,6 +285,7 @@ public class PdpGroupDeployProvider extends ProviderBase {
                 // this subgroup no longer appears - notify its PDPs
                 updated = true;
                 notifyPdpsDelSubGroup(data, subgrp);
+                trackPdpsDelSubGroup(data, subgrp);
             }
         }
 
@@ -314,10 +316,26 @@ public class PdpGroupDeployProvider extends ProviderBase {
     }
 
     /**
+     * Tracks PDP responses when their subgroup is removed.
+     *
+     * @param data session data
+     * @param subgrp subgroup that is being removed
+     * @throws PfModelException if an error occurred
+     */
+    private void trackPdpsDelSubGroup(SessionData data, PdpSubGroup subgrp) throws PfModelException {
+        Set<String> pdps = subgrp.getPdpInstances().stream().map(Pdp::getInstanceId).collect(Collectors.toSet());
+
+        for (ToscaPolicyIdentifier policyId : subgrp.getPolicies()) {
+            data.trackUndeploy(policyId, pdps);
+        }
+    }
+
+    /**
      * Adds a new subgroup.
      *
      * @param data session data
-     * @param subgrp the subgroup to be added, updated to fully qualified versions upon return
+     * @param subgrp the subgroup to be added, updated to fully qualified versions upon
+     *        return
      * @return the validation result
      * @throws PfModelException if an error occurred
      */
@@ -339,7 +357,8 @@ public class PdpGroupDeployProvider extends ProviderBase {
      * @param data session data
      * @param dbgroup the group, from the DB, containing the subgroup
      * @param dbsub the subgroup, from the DB
-     * @param subgrp the subgroup to be updated, updated to fully qualified versions upon return
+     * @param subgrp the subgroup to be updated, updated to fully qualified versions upon
+     *        return
      * @param container container for additional validation results
      * @return {@code true} if the subgroup content was changed, {@code false} if there
      *         were no changes
@@ -356,7 +375,7 @@ public class PdpGroupDeployProvider extends ProviderBase {
         /*
          * first, apply the changes about which the PDPs care
          */
-        boolean updated = updateList(dbsub.getPolicies(), subgrp.getPolicies(), dbsub::setPolicies);
+        boolean updated = updatePolicies(data, dbsub, subgrp);
 
         // publish any changes to the PDPs
         if (updated) {
@@ -373,12 +392,40 @@ public class PdpGroupDeployProvider extends ProviderBase {
                         dbsub::setDesiredInstanceCount) || updated;
     }
 
+    private boolean updatePolicies(SessionData data, PdpSubGroup dbsub, PdpSubGroup subgrp) throws PfModelException {
+        Set<ToscaPolicyIdentifier> undeployed = new HashSet<>(dbsub.getPolicies());
+        undeployed.removeAll(subgrp.getPolicies());
+
+        Set<ToscaPolicyIdentifier> deployed = new HashSet<>(subgrp.getPolicies());
+        deployed.removeAll(dbsub.getPolicies());
+
+        if (deployed.isEmpty() && undeployed.isEmpty()) {
+            // lists are identical
+            return false;
+        }
+
+
+        Set<String> pdps = subgrp.getPdpInstances().stream().map(Pdp::getInstanceId).collect(Collectors.toSet());
+
+        for (ToscaPolicyIdentifier policyId : deployed) {
+            data.trackDeploy(policyId, pdps);
+        }
+
+        for (ToscaPolicyIdentifier policyId : undeployed) {
+            data.trackUndeploy(policyId, pdps);
+        }
+
+        dbsub.setPolicies(new ArrayList<>(subgrp.getPolicies()));
+        return true;
+    }
+
     /**
      * Performs additional validations of a subgroup.
      *
      * @param data session data
      * @param dbsub the subgroup, from the DB
-     * @param subgrp the subgroup to be validated, updated to fully qualified versions upon return
+     * @param subgrp the subgroup to be validated, updated to fully qualified versions
+     *        upon return
      * @param container container for additional validation results
      * @return {@code true} if the subgroup is valid, {@code false} otherwise
      * @throws PfModelException if an error occurred
@@ -455,7 +502,8 @@ public class PdpGroupDeployProvider extends ProviderBase {
     private ValidationResult validatePolicies(SessionData data, PdpSubGroup dbsub, PdpSubGroup subgrp)
                     throws PfModelException {
 
-        // build a map of the DB data, from policy name to (fully qualified) policy version
+        // build a map of the DB data, from policy name to (fully qualified) policy
+        // version
         Map<String, String> dbname2vers = new HashMap<>();
         if (dbsub != null) {
             dbsub.getPolicies().forEach(ident -> dbname2vers.put(ident.getName(), ident.getVersion()));
@@ -557,7 +605,7 @@ public class PdpGroupDeployProvider extends ProviderBase {
      * Adds a policy to a subgroup, if it isn't there already.
      */
     @Override
-    protected BiFunction<PdpGroup, PdpSubGroup, Boolean> makeUpdater(ToscaPolicy policy,
+    protected Updater makeUpdater(SessionData data, ToscaPolicy policy,
                     ToscaPolicyIdentifierOptVersion requestedIdent) {
 
         ToscaPolicyIdentifier desiredIdent = policy.getIdentifier();
@@ -586,6 +634,10 @@ public class PdpGroupDeployProvider extends ProviderBase {
             logger.info("add policy {} {} to subgroup {} {} count={}", desiredIdent.getName(),
                             desiredIdent.getVersion(), group.getName(), subgroup.getPdpType(),
                             subgroup.getPolicies().size());
+
+            Set<String> pdps = subgroup.getPdpInstances().stream().map(Pdp::getInstanceId).collect(Collectors.toSet());
+            data.trackDeploy(desiredIdent, pdps);
+
             return true;
         };
     }
diff --git a/main/src/main/java/org/onap/policy/pap/main/rest/depundep/ProviderBase.java b/main/src/main/java/org/onap/policy/pap/main/rest/depundep/ProviderBase.java
index 70ccd7ab..fd8edf17 100644
--- a/main/src/main/java/org/onap/policy/pap/main/rest/depundep/ProviderBase.java
+++ b/main/src/main/java/org/onap/policy/pap/main/rest/depundep/ProviderBase.java
@@ -21,17 +21,13 @@
 package org.onap.policy.pap.main.rest.depundep;
 
 import java.util.Collection;
-import java.util.Collections;
-import java.util.function.BiFunction;
 import java.util.stream.Collectors;
 import javax.ws.rs.core.Response.Status;
-import org.apache.commons.lang3.tuple.Pair;
 import org.onap.policy.common.utils.services.Registry;
 import org.onap.policy.models.base.PfModelException;
 import org.onap.policy.models.base.PfModelRuntimeException;
 import org.onap.policy.models.pdp.concepts.Pdp;
 import org.onap.policy.models.pdp.concepts.PdpGroup;
-import org.onap.policy.models.pdp.concepts.PdpStateChange;
 import org.onap.policy.models.pdp.concepts.PdpSubGroup;
 import org.onap.policy.models.pdp.concepts.PdpUpdate;
 import org.onap.policy.models.provider.PolicyModelsProvider;
@@ -41,6 +37,7 @@ import org.onap.policy.models.tosca.authorative.concepts.ToscaPolicyTypeIdentifi
 import org.onap.policy.pap.main.PapConstants;
 import org.onap.policy.pap.main.PolicyModelsProviderFactoryWrapper;
 import org.onap.policy.pap.main.comm.PdpModifyRequestMap;
+import org.onap.policy.pap.main.notification.PolicyNotifier;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -70,6 +67,11 @@ public abstract class ProviderBase {
     private final PdpModifyRequestMap requestMap;
 
     /**
+     * Generates policy notifications based on responses from PDPs.
+     */
+    private final PolicyNotifier notifier;
+
+    /**
      * Factory for PAP DAO.
      */
     private final PolicyModelsProviderFactoryWrapper daoFactory;
@@ -82,6 +84,7 @@ public abstract class ProviderBase {
         this.updateLock = Registry.get(PapConstants.REG_PDP_MODIFY_LOCK, Object.class);
         this.requestMap = Registry.get(PapConstants.REG_PDP_MODIFY_MAP, PdpModifyRequestMap.class);
         this.daoFactory = Registry.get(PapConstants.REG_PAP_DAO_FACTORY, PolicyModelsProviderFactoryWrapper.class);
+        this.notifier = Registry.get(PapConstants.REG_POLICY_NOTIFIER, PolicyNotifier.class);
     }
 
     /**
@@ -94,19 +97,16 @@ public abstract class ProviderBase {
     protected <T> void process(T request, BiConsumerWithEx<SessionData, T> processor) throws PfModelException {
 
         synchronized (updateLock) {
-            // list of requests to be published to the PDPs
-            Collection<Pair<PdpUpdate, PdpStateChange>> requests = Collections.emptyList();
+            SessionData data;
 
             try (PolicyModelsProvider dao = daoFactory.create()) {
 
-                SessionData data = new SessionData(dao);
+                data = new SessionData(dao);
                 processor.accept(data, request);
 
                 // make all of the DB updates
                 data.updateDb();
 
-                requests = data.getPdpRequests();
-
             } catch (PfModelException | PfModelRuntimeException e) {
                 logger.warn(DEPLOY_FAILED, e);
                 throw e;
@@ -116,9 +116,12 @@ public abstract class ProviderBase {
                 throw new PfModelException(Status.INTERNAL_SERVER_ERROR, "request failed", e);
             }
 
+            // track responses for notification purposes
+            data.getDeployData().forEach(notifier::addDeploymentData);
+            data.getUndeployData().forEach(notifier::addUndeploymentData);
 
             // publish the requests
-            requests.forEach(pair -> requestMap.addRequest(pair.getLeft(), pair.getRight()));
+            data.getPdpRequests().forEach(pair -> requestMap.addRequest(pair.getLeft(), pair.getRight()));
         }
     }
 
@@ -140,7 +143,7 @@ public abstract class ProviderBase {
                             + desiredPolicy.getName() + " " + desiredPolicy.getVersion());
         }
 
-        BiFunction<PdpGroup, PdpSubGroup, Boolean> updater = makeUpdater(policy, desiredPolicy);
+        Updater updater = makeUpdater(data, policy, desiredPolicy);
 
         for (PdpGroup group : groups) {
             upgradeGroup(data, group, updater);
@@ -152,11 +155,12 @@ public abstract class ProviderBase {
      * {@code true} if the subgroup was updated, {@code false} if no update was
      * necessary/appropriate.
      *
+     * @param data session data
      * @param policy policy to be added to or removed from each subgroup
      * @param desiredPolicy request policy
      * @return a function to update a subgroup
      */
-    protected abstract BiFunction<PdpGroup, PdpSubGroup, Boolean> makeUpdater(ToscaPolicy policy,
+    protected abstract Updater makeUpdater(SessionData data, ToscaPolicy policy,
                     ToscaPolicyIdentifierOptVersion desiredPolicy);
 
     /**
@@ -180,9 +184,9 @@ public abstract class ProviderBase {
      * @param data session data
      * @param group the original group, to be updated
      * @param updater function to update a group
-     * @throws PfModelRuntimeException if an error occurred
+     * @throws PfModelException if an error occurred
      */
-    private void upgradeGroup(SessionData data, PdpGroup group, BiFunction<PdpGroup, PdpSubGroup, Boolean> updater) {
+    private void upgradeGroup(SessionData data, PdpGroup group, Updater updater) throws PfModelException {
 
         boolean updated = false;
 
@@ -275,4 +279,9 @@ public abstract class ProviderBase {
          */
         void accept(F firstArg, S secondArg) throws PfModelException;
     }
+
+    @FunctionalInterface
+    public static interface Updater {
+        boolean apply(PdpGroup group, PdpSubGroup subgroup) throws PfModelException;
+    }
 }
diff --git a/main/src/main/java/org/onap/policy/pap/main/rest/depundep/SessionData.java b/main/src/main/java/org/onap/policy/pap/main/rest/depundep/SessionData.java
index 437d7a11..5b2a8eea 100644
--- a/main/src/main/java/org/onap/policy/pap/main/rest/depundep/SessionData.java
+++ b/main/src/main/java/org/onap/policy/pap/main/rest/depundep/SessionData.java
@@ -23,8 +23,10 @@ package org.onap.policy.pap.main.rest.depundep;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 import java.util.regex.Pattern;
 import java.util.stream.Collectors;
 import org.apache.commons.lang3.tuple.Pair;
@@ -38,9 +40,11 @@ import org.onap.policy.models.provider.PolicyModelsProvider;
 import org.onap.policy.models.tosca.authorative.concepts.ToscaPolicy;
 import org.onap.policy.models.tosca.authorative.concepts.ToscaPolicyFilter;
 import org.onap.policy.models.tosca.authorative.concepts.ToscaPolicyFilter.ToscaPolicyFilterBuilder;
+import org.onap.policy.models.tosca.authorative.concepts.ToscaPolicyIdentifier;
 import org.onap.policy.models.tosca.authorative.concepts.ToscaPolicyIdentifierOptVersion;
 import org.onap.policy.models.tosca.authorative.concepts.ToscaPolicyType;
 import org.onap.policy.models.tosca.authorative.concepts.ToscaPolicyTypeIdentifier;
+import org.onap.policy.pap.main.notification.PolicyPdpNotificationData;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -88,6 +92,18 @@ public class SessionData {
      */
     private final Map<ToscaPolicyTypeIdentifier, ToscaPolicyType> typeCache = new HashMap<>();
 
+    /**
+     * Policies to be deployed. This is just used to build up the data, which is then
+     * passed to the notifier once the update is "committed".
+     */
+    private final Map<ToscaPolicyIdentifier, PolicyPdpNotificationData> deploy = new HashMap<>();
+
+    /**
+     * Policies to be undeployed. This is just used to build up the data, which is then
+     * passed to the notifier once the update is "committed".
+     */
+    private final Map<ToscaPolicyIdentifier, PolicyPdpNotificationData> undeploy = new HashMap<>();
+
 
     /**
      * Constructs the object.
@@ -402,4 +418,90 @@ public class SessionData {
         logger.info("deleting DB group {}", group.getName());
         dao.deletePdpGroup(group.getName());
     }
+
+    /**
+     * Adds policy deployment data.
+     *
+     * @param policyId ID of the policy being deployed
+     * @param pdps PDPs to which the policy is being deployed
+     * @throws PfModelException if an error occurred
+     */
+    protected void trackDeploy(ToscaPolicyIdentifier policyId, Collection<String> pdps) throws PfModelException {
+        trackDeploy(policyId, new HashSet<>(pdps));
+    }
+
+    /**
+     * Adds policy deployment data.
+     *
+     * @param policyId ID of the policy being deployed
+     * @param pdps PDPs to which the policy is being deployed
+     * @throws PfModelException if an error occurred
+     */
+    protected void trackDeploy(ToscaPolicyIdentifier policyId, Set<String> pdps) throws PfModelException {
+        addData(policyId, pdps, deploy, undeploy);
+    }
+
+    /**
+     * Adds policy undeployment data.
+     *
+     * @param policyId ID of the policy being undeployed
+     * @param pdps PDPs to which the policy is being undeployed
+     * @throws PfModelException if an error occurred
+     */
+    protected void trackUndeploy(ToscaPolicyIdentifier policyId, Collection<String> pdps) throws PfModelException {
+        trackUndeploy(policyId, new HashSet<>(pdps));
+    }
+
+    /**
+     * Adds policy undeployment data.
+     *
+     * @param policyId ID of the policy being undeployed
+     * @param pdps PDPs to which the policy is being undeployed
+     * @throws PfModelException if an error occurred
+     */
+    protected void trackUndeploy(ToscaPolicyIdentifier policyId, Set<String> pdps) throws PfModelException {
+        addData(policyId, pdps, undeploy, deploy);
+    }
+
+    /**
+     * Adds policy deployment/undeployment data.
+     *
+     * @param policyId ID of the policy being deployed/undeployed
+     * @param pdps PDPs to which the policy is being deployed/undeployed
+     * @param addMap map to which it should be added
+     * @param removeMap map from which it should be removed
+     * @throws PfModelException if an error occurred
+     */
+    private void addData(ToscaPolicyIdentifier policyId, Set<String> pdps,
+                    Map<ToscaPolicyIdentifier, PolicyPdpNotificationData> addMap,
+                    Map<ToscaPolicyIdentifier, PolicyPdpNotificationData> removeMap) throws PfModelException {
+
+        PolicyPdpNotificationData removeData = removeMap.get(policyId);
+        if (removeData != null) {
+            removeData.removeAll(pdps);
+        }
+
+        ToscaPolicyIdentifierOptVersion optid = new ToscaPolicyIdentifierOptVersion(policyId);
+        ToscaPolicyTypeIdentifier policyType = getPolicy(optid).getTypeIdentifier();
+
+        addMap.computeIfAbsent(policyId, key -> new PolicyPdpNotificationData(policyId, policyType)).addAll(pdps);
+    }
+
+    /**
+     * Gets the policies to be deployed.
+     *
+     * @return the policies to be deployed
+     */
+    public Collection<PolicyPdpNotificationData> getDeployData() {
+        return deploy.values();
+    }
+
+    /**
+     * Gets the policies to be undeployed.
+     *
+     * @return the policies to be undeployed
+     */
+    public Collection<PolicyPdpNotificationData> getUndeployData() {
+        return undeploy.values();
+    }
 }
diff --git a/main/src/main/java/org/onap/policy/pap/main/startstop/PapActivator.java b/main/src/main/java/org/onap/policy/pap/main/startstop/PapActivator.java
index d119044f..8d2fd3ea 100644
--- a/main/src/main/java/org/onap/policy/pap/main/startstop/PapActivator.java
+++ b/main/src/main/java/org/onap/policy/pap/main/startstop/PapActivator.java
@@ -31,6 +31,8 @@ import org.onap.policy.common.endpoints.listeners.RequestIdDispatcher;
 import org.onap.policy.common.parameters.ParameterService;
 import org.onap.policy.common.utils.services.Registry;
 import org.onap.policy.common.utils.services.ServiceManagerContainer;
+import org.onap.policy.models.pap.concepts.PolicyNotification;
+import org.onap.policy.models.pdp.concepts.PdpMessage;
 import org.onap.policy.models.pdp.concepts.PdpStatus;
 import org.onap.policy.models.pdp.enums.PdpMessageType;
 import org.onap.policy.pap.main.PapConstants;
@@ -41,6 +43,7 @@ import org.onap.policy.pap.main.comm.PdpModifyRequestMap;
 import org.onap.policy.pap.main.comm.PdpTracker;
 import org.onap.policy.pap.main.comm.Publisher;
 import org.onap.policy.pap.main.comm.TimerManager;
+import org.onap.policy.pap.main.notification.PolicyNotifier;
 import org.onap.policy.pap.main.parameters.PapParameterGroup;
 import org.onap.policy.pap.main.parameters.PdpModifyRequestMapParams;
 import org.onap.policy.pap.main.parameters.PdpParameters;
@@ -112,13 +115,15 @@ public class PapActivator extends ServiceManagerContainer {
 
         final Object pdpUpdateLock = new Object();
         final PdpParameters pdpParams = papParameterGroup.getPdpParameters();
-        final AtomicReference<Publisher> pdpPub = new AtomicReference<>();
+        final AtomicReference<Publisher<PdpMessage>> pdpPub = new AtomicReference<>();
+        final AtomicReference<Publisher<PolicyNotification>> notifyPub = new AtomicReference<>();
         final AtomicReference<TimerManager> pdpUpdTimers = new AtomicReference<>();
         final AtomicReference<TimerManager> pdpStChgTimers = new AtomicReference<>();
         final AtomicReference<TimerManager> heartBeatTimers = new AtomicReference<>();
         final AtomicReference<PolicyModelsProviderFactoryWrapper> daoFactory = new AtomicReference<>();
         final AtomicReference<PdpModifyRequestMap> requestMap = new AtomicReference<>();
         final AtomicReference<RestServer> restServer = new AtomicReference<>();
+        final AtomicReference<PolicyNotifier> notifier = new AtomicReference<>();
 
         // @formatter:off
         addAction("PAP parameters",
@@ -156,11 +161,23 @@ public class PapActivator extends ServiceManagerContainer {
 
         addAction("PDP publisher",
             () -> {
-                pdpPub.set(new Publisher(PapConstants.TOPIC_POLICY_PDP_PAP));
+                pdpPub.set(new Publisher<>(PapConstants.TOPIC_POLICY_PDP_PAP));
                 startThread(pdpPub.get());
             },
             () -> pdpPub.get().stop());
 
+        addAction("Policy Notification publisher",
+            () -> {
+                notifyPub.set(new Publisher<>(PapConstants.TOPIC_POLICY_NOTIFICATION));
+                startThread(notifyPub.get());
+                notifier.set(new PolicyNotifier(notifyPub.get()));
+            },
+            () -> notifyPub.get().stop());
+
+        addAction("Policy Notifier",
+            () -> Registry.register(PapConstants.REG_POLICY_NOTIFIER, notifier.get()),
+            () -> Registry.unregister(PapConstants.REG_POLICY_NOTIFIER));
+
         addAction("PDP heart beat timers",
             () -> {
                 long maxWaitHeartBeatMs = MAX_MISSED_HEARTBEATS * pdpParams.getHeartBeatMs();
@@ -194,7 +211,8 @@ public class PapActivator extends ServiceManagerContainer {
                                     .setDaoFactory(daoFactory.get())
                                     .setModifyLock(pdpUpdateLock)
                                     .setParams(pdpParams)
-                                    .setPublisher(pdpPub.get())
+                                    .setPolicyNotifier(notifier.get())
+                                    .setPdpPublisher(pdpPub.get())
                                     .setResponseDispatcher(reqIdDispatcher)
                                     .setStateChangeTimers(pdpStChgTimers.get())
                                     .setUpdateTimers(pdpUpdTimers.get())));