Fix NullPointerException with -s flag; add -s message

Change-Id: I6bc1e2326d0d260a0469e64b8d0ec2937694534c

@@ -22,13 +22,14 @@ import org.onosproject.cli.AbstractShellCommand;
 import org.onosproject.core.ApplicationId;
 import org.onosproject.core.ApplicationId;
 import org.onosproject.core.CoreService;
 import org.onosproject.core.CoreService;
 import org.onosproject.net.intent.Intent;
 import org.onosproject.net.intent.Intent;
-import org.onosproject.net.intent.IntentEvent;
-import org.onosproject.net.intent.IntentListener;
-import org.onosproject.net.intent.IntentService;
 import org.onosproject.net.intent.IntentState;
 import org.onosproject.net.intent.IntentState;
+import org.onosproject.net.intent.IntentService;
+import org.onosproject.net.intent.IntentListener;
+import org.onosproject.net.intent.IntentEvent;
 import org.onosproject.net.intent.Key;
 import org.onosproject.net.intent.Key;
 
 
 import java.math.BigInteger;
 import java.math.BigInteger;
+import java.util.EnumSet;
 import java.util.Objects;
 import java.util.Objects;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.TimeUnit;
@@ -64,11 +65,18 @@ public class IntentRemoveCommand extends AbstractShellCommand {
             required = false, multiValued = false)
             required = false, multiValued = false)
     private boolean sync = false;
     private boolean sync = false;
 
 
+    private static final EnumSet<IntentState> CAN_PURGE = EnumSet.of(WITHDRAWN, FAILED);
+
     @Override
     @Override
     protected void execute() {
     protected void execute() {
         IntentService intentService = get(IntentService.class);
         IntentService intentService = get(IntentService.class);
         CoreService coreService = get(CoreService.class);
         CoreService coreService = get(CoreService.class);
 
 
+        if (sync) {
+            print("Use Sync to remove intents - this may take a while...");
+            print("Check \"summary\" to see remove progress.");
+        }
+
         ApplicationId appId = appId();
         ApplicationId appId = appId();
         if (!isNullOrEmpty(applicationIdString)) {
         if (!isNullOrEmpty(applicationIdString)) {
             appId = coreService.getAppId(applicationIdString);
             appId = coreService.getAppId(applicationIdString);
@@ -137,21 +145,19 @@ public class IntentRemoveCommand extends AbstractShellCommand {
             } catch (InterruptedException e) {
             } catch (InterruptedException e) {
                 print("Timed out waiting for intent {} withdraw", key);
                 print("Timed out waiting for intent {} withdraw", key);
             }
             }
-            // double check the state
-            IntentState state = intentService.getIntentState(key);
-            if (purgeAfterRemove && (state == WITHDRAWN || state == FAILED)) {
+            if (purgeAfterRemove && CAN_PURGE.contains(intentService.getIntentState(key))) {
                 intentService.purge(intent);
                 intentService.purge(intent);
-            }
-            if (sync) { // wait for purge event
+                if (sync) { // wait for purge event
                     /* TODO
                     /* TODO
                        Technically, the event comes before map.remove() is called.
                        Technically, the event comes before map.remove() is called.
                        If we depend on sync and purge working together, we will
                        If we depend on sync and purge working together, we will
                        need to address this.
                        need to address this.
                     */
                     */
-                try {
-                    purgeLatch.await(5, TimeUnit.SECONDS);
-                } catch (InterruptedException e) {
-                    print("Timed out waiting for intent {} purge", key);
+                    try {
+                        purgeLatch.await(5, TimeUnit.SECONDS);
+                    } catch (InterruptedException e) {
+                        print("Timed out waiting for intent {} purge", key);
+                    }
                 }
                 }
             }
             }
         }
         }