* Jandor's Ring - FIxed possible null pointer exception (discard has to be a cost still lacking).

Mage.Sets/src/mage/cards/j/JandorsRing.java

@@ -27,6 +27,8 @@
  */
 package mage.cards.j;
 
+import java.util.HashMap;
+import java.util.Map;
 import java.util.UUID;
 import mage.abilities.Ability;
 import mage.abilities.condition.Condition;
@@ -35,6 +37,7 @@ import mage.abilities.costs.mana.ManaCostsImpl;
 import mage.abilities.decorator.ConditionalActivatedAbility;
 import mage.abilities.effects.OneShotEffect;
 import mage.abilities.effects.common.discard.DiscardCardYouChooseTargetEffect;
+import mage.cards.Card;
 import mage.cards.CardImpl;
 import mage.cards.CardSetInfo;
 import mage.constants.CardType;
@@ -59,7 +62,9 @@ public class JandorsRing extends CardImpl {
 
         Watcher watcher = new JandorsRingWatcher();
         // {2}, {tap}, Discard the last card you drew this turn: Draw a card.
-        Ability ability = new ConditionalActivatedAbility(Zone.BATTLEFIELD, new DiscardAndDrawEffect(), new ManaCostsImpl("{2}"), WatchedCardInHandCondition.instance, "Last drawn card still in hand?");
+        // TODO: discard has to be a cost not a payment during resolution
+        Ability ability = new ConditionalActivatedAbility(Zone.BATTLEFIELD,
+                new JandorsRingEffect(), new ManaCostsImpl("{2}"), WatchedCardInHandCondition.instance, "Last drawn card still in hand?");
         ability.addCost(new TapSourceCost());
         this.addAbility(ability, watcher);
     }
@@ -74,61 +79,60 @@ public class JandorsRing extends CardImpl {
     }
 }
 
-class DiscardAndDrawEffect extends OneShotEffect {
+class JandorsRingEffect extends OneShotEffect {
 
-
+    public JandorsRingEffect() {
-    public DiscardAndDrawEffect() {
         super(Outcome.Discard);
+        staticText = "Draw a card";
     }
 
-    public DiscardAndDrawEffect(final DiscardAndDrawEffect effect) {
+    public JandorsRingEffect(final JandorsRingEffect effect) {
         super(effect);
     }
 
     @Override
-    public DiscardAndDrawEffect copy() {
+    public JandorsRingEffect copy() {
-        return new DiscardAndDrawEffect(this);
+        return new JandorsRingEffect(this);
     }
 
     @Override
     public boolean apply(Game game, Ability source) {
         JandorsRingWatcher watcher = (JandorsRingWatcher) game.getState().getWatchers().get(JandorsRingWatcher.class.getSimpleName());
-
+        if (watcher != null) {
-        FilterCard filter = new FilterCard(game.getCard(watcher.lastDrawnCard).getName());
+            UUID cardId = watcher.getLastDrewCard(source.getControllerId());
-        filter.add(new CardIdPredicate(watcher.lastDrawnCard));
+            Card card = game.getCard(cardId);
+            if (card != null) {
+                FilterCard filter = new FilterCard(card.getName());
+                filter.add(new CardIdPredicate(card.getId()));
                 DiscardCardYouChooseTargetEffect effect = new DiscardCardYouChooseTargetEffect(filter, TargetController.YOU);
-
                 if (effect.apply(game, source)) {//Conditional was already checked, card should be in hand, but if for some weird reason it fails, the card won't be drawn, although the cost will already be paid
                     Player controller = game.getPlayer(source.getControllerId());
                     controller.drawCards(1, game);
+                }
+            }
             return true;
         }
         return false;
     }
 }
 
-
 class JandorsRingWatcher extends Watcher {
 
-    UUID lastDrawnCard;
+    Map<UUID, UUID> lastDrawnCards = new HashMap<>();
 
     public JandorsRingWatcher() {
-        super(JandorsRingWatcher.class.getSimpleName(), WatcherScope.PLAYER);
+        super(JandorsRingWatcher.class.getSimpleName(), WatcherScope.GAME);
-        this.lastDrawnCard = null;
     }
 
     public JandorsRingWatcher(final JandorsRingWatcher watcher) {
         super(watcher);
-        this.lastDrawnCard = watcher.lastDrawnCard;
+        this.lastDrawnCards.putAll(watcher.lastDrawnCards);
     }
 
     @Override
     public void watch(GameEvent event, Game game) {
         if (event.getType() == GameEvent.EventType.DREW_CARD) {
-            lastDrawnCard = event.getTargetId();
+            lastDrawnCards.putIfAbsent(event.getPlayerId(), event.getTargetId());
-        }
-        if (event.getType() == GameEvent.EventType.CLEANUP_STEP_POST) {
-            lastDrawnCard = null;
         }
     }
 
@@ -140,7 +144,11 @@ class JandorsRingWatcher extends Watcher {
     @Override
     public void reset() {
         super.reset();
-        lastDrawnCard = null;
+        lastDrawnCards.clear();
+    }
+
+    public UUID getLastDrewCard(UUID playerId) {
+        return lastDrawnCards.getOrDefault(null, playerId);
     }
 }
 
@@ -152,7 +160,8 @@ enum WatchedCardInHandCondition implements Condition {
     public boolean apply(Game game, Ability source) {
         JandorsRingWatcher watcher = (JandorsRingWatcher) game.getState().getWatchers().get(JandorsRingWatcher.class.getSimpleName());
 
-        return watcher.lastDrawnCard != null && game.getPlayer(source.getControllerId()).getHand().contains(watcher.lastDrawnCard);
+        return watcher != null
+                && watcher.lastDrawnCards != null && game.getPlayer(source.getControllerId()).getHand().contains(watcher.getLastDrewCard(source.getControllerId()));
     }
 
     @Override
@@ -160,5 +169,4 @@ enum WatchedCardInHandCondition implements Condition {
         return "if last drawn card is still in hand";
     }
 
-
 }

Mage/src/main/java/mage/watchers/common/CastFromHandWatcher.java

@@ -4,7 +4,6 @@ import java.util.HashSet;
 import java.util.Objects;
 import java.util.Set;
 import java.util.UUID;
-
 import mage.constants.WatcherScope;
 import mage.constants.Zone;
 import mage.game.Game;
@@ -43,9 +42,11 @@ public class CastFromHandWatcher extends Watcher {
                 step = game.getTurn().getStep();
             }
             Spell spell = (Spell) game.getObject(event.getTargetId());
+            if (spell != null) {
                 spellsCastFromHand.add(spell.getSourceId());
             }
         }
+    }
 
     public boolean spellWasCastFromHand(UUID sourceId) {
         return spellsCastFromHand.contains(sourceId);