added TransformIntoSourceTriggeredAbility to simplify copied code

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

@@ -0,0 +1,58 @@
+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.permanent.Permanent;
+
+/**
+ * @author TheElk801
+ */
+public class TransformIntoSourceTriggeredAbility extends TriggeredAbilityImpl {
+
+    private final boolean whenever;
+
+    public TransformIntoSourceTriggeredAbility(Effect effect) {
+        this(effect, false);
+    }
+
+    public TransformIntoSourceTriggeredAbility(Effect effect, boolean optional) {
+        this(effect, optional, false);
+    }
+
+    public TransformIntoSourceTriggeredAbility(Effect effect, boolean optional, boolean whenever) {
+        super(Zone.BATTLEFIELD, effect, optional);
+        this.whenever = whenever;
+    }
+
+    private TransformIntoSourceTriggeredAbility(final TransformIntoSourceTriggeredAbility ability) {
+        super(ability);
+        this.whenever = ability.whenever;
+    }
+
+    @Override
+    public TransformIntoSourceTriggeredAbility copy() {
+        return new TransformIntoSourceTriggeredAbility(this);
+    }
+
+    @Override
+    public boolean checkEventType(GameEvent event, Game game) {
+        return event.getType() == GameEvent.EventType.TRANSFORMED;
+    }
+
+    @Override
+    public boolean checkTrigger(GameEvent event, Game game) {
+        if (!event.getTargetId().equals(this.getSourceId())) {
+            return false;
+        }
+        Permanent permanent = getSourcePermanentIfItStillExists(game);
+        return permanent != null && permanent.isTransformed();
+    }
+
+    @Override
+    public String getTriggerPhrase() {
+        return "When" + (whenever ? "ever" : "") + " this creature transforms into this {this}, ";
+    }
+}