Implemented Ajani's Last Stand

Mage/src/main/java/mage/abilities/common/DiscardedByOpponentTriggeredAbility.java

@@ -0,0 +1,54 @@
+package mage.abilities.common;
+
+import mage.abilities.TriggeredAbilityImpl;
+import mage.abilities.effects.Effect;
+import mage.constants.Zone;
+import mage.game.Game;
+import mage.game.events.GameEvent;
+import mage.game.events.GameEvent.EventType;
+import mage.game.stack.StackObject;
+
+/**
+ *
+ * @author Styxo
+ */
+public class DiscardedByOpponentTriggeredAbility extends TriggeredAbilityImpl {
+
+    public DiscardedByOpponentTriggeredAbility(Effect effect) {
+        this(effect, false);
+    }
+
+    public DiscardedByOpponentTriggeredAbility(Effect effect, boolean optional) {
+        super(Zone.GRAVEYARD, effect, optional);
+    }
+
+    public DiscardedByOpponentTriggeredAbility(final DiscardedByOpponentTriggeredAbility ability) {
+        super(ability);
+    }
+
+    @Override
+    public DiscardedByOpponentTriggeredAbility copy() {
+        return new DiscardedByOpponentTriggeredAbility(this);
+    }
+
+    @Override
+    public boolean checkEventType(GameEvent event, Game game) {
+        return event.getType() == EventType.DISCARDED_CARD;
+    }
+
+    @Override
+    public boolean checkTrigger(GameEvent event, Game game) {
+        if (getSourceId().equals(event.getTargetId())) {
+            StackObject stackObject = game.getStack().getStackObject(event.getSourceId());
+            if (stackObject != null) {
+                return game.getOpponents(this.getControllerId()).contains(stackObject.getControllerId());
+            }
+        }
+        return false;
+    }
+
+    @Override
+    public String getRule() {
+        return "When a spell or ability an opponent controls causes you to discard this card, " + super.getRule();
+    }
+}