Some minor code reworks.

Mage.Sets/src/mage/sets/championsofkamigawa/CallousDeceiver.java

@@ -28,19 +28,14 @@
 package mage.sets.championsofkamigawa;
 
 import java.util.UUID;
-
-import mage.constants.CardType;
-import mage.constants.Duration;
-import mage.constants.Rarity;
-import mage.constants.Zone;
 import mage.MageInt;
+import mage.MageObject;
 import mage.abilities.Ability;
 import mage.abilities.common.LimitedTimesPerTurnActivatedAbility;
-import mage.abilities.costs.mana.GenericManaCost;
 import mage.abilities.common.SimpleActivatedAbility;
-import mage.abilities.costs.Cost;
+import mage.abilities.costs.mana.GenericManaCost;
 import mage.abilities.costs.mana.ManaCostsImpl;
-import mage.abilities.effects.Effect;
+import mage.abilities.effects.OneShotEffect;
 import mage.abilities.effects.common.LookLibraryControllerEffect;
 import mage.abilities.effects.common.continuous.BoostSourceEffect;
 import mage.abilities.effects.common.continuous.GainAbilitySourceEffect;
@@ -49,6 +44,11 @@ import mage.cards.Card;
 import mage.cards.CardImpl;
 import mage.cards.Cards;
 import mage.cards.CardsImpl;
+import mage.constants.CardType;
+import mage.constants.Duration;
+import mage.constants.Outcome;
+import mage.constants.Rarity;
+import mage.constants.Zone;
 import mage.game.Game;
 import mage.players.Player;
 
@@ -68,10 +68,8 @@ public class CallousDeceiver extends CardImpl {
         // {1}: Look at the top card of your library.
         this.addAbility(new SimpleActivatedAbility(Zone.BATTLEFIELD, new LookLibraryControllerEffect(), new GenericManaCost(1)));
 
-        // {2}: Reveal the top card of your library. If it's a land card, {this} gets +1/+0 and gains flying until end of turn.
+        // {2}: Reveal the top card of your library. If it's a land card, {this} gets +1/+0 and gains flying until end of turn. Activate this ability only once each turn.
-        Ability ability = new CallousDeceiverAbility(Zone.BATTLEFIELD, new BoostSourceEffect(1,0,Duration.EndOfTurn), new ManaCostsImpl("{2}"));
+        this.addAbility(new LimitedTimesPerTurnActivatedAbility(Zone.BATTLEFIELD, new CallousDeceiverEffect(), new ManaCostsImpl("{2}")));
-        ability.addEffect(new GainAbilitySourceEffect(FlyingAbility.getInstance(),Duration.EndOfTurn));
-        this.addAbility(ability);
     }
 
     public CallousDeceiver(final CallousDeceiver card) {
@@ -85,38 +83,39 @@ public class CallousDeceiver extends CardImpl {
 
 }
 
-class CallousDeceiverAbility extends LimitedTimesPerTurnActivatedAbility {
+class CallousDeceiverEffect extends OneShotEffect {
 
-        public CallousDeceiverAbility(Zone zone, Effect effect, Cost cost) {
+    public CallousDeceiverEffect() {
-        super(zone, effect, cost);
+        super(Outcome.BoostCreature);
+        this.staticText = "Reveal the top card of your library. If it's a land card, {this} gets +1/+0 and gains flying until end of turn";
     }
 
-        public CallousDeceiverAbility(CallousDeceiverAbility ability) {
+    public CallousDeceiverEffect(final CallousDeceiverEffect effect) {
-        super(ability);
+        super(effect);
     }
 
-        @Override
+    @Override
-        public CallousDeceiverAbility copy() {
+    public CallousDeceiverEffect copy() {
-                return new CallousDeceiverAbility(this);
+        return new CallousDeceiverEffect(this);
-        }
+    }
 
-        @Override
+    @Override
-    public boolean checkIfClause(Game game) {
+    public boolean apply(Game game, Ability source) {
-                Player player = game.getPlayer(this.getControllerId());
+        Player controller = game.getPlayer(source.getControllerId());
-                if (player != null) {
+        MageObject sourceObject = source.getSourceObject(game);
-                    Cards cards = new CardsImpl();
+        if (controller != null && sourceObject != null) {
-                    Card card = player.getLibrary().getFromTop(game);
+            Cards cards = new CardsImpl();
-                    cards.add(card);
+            Card card = controller.getLibrary().getFromTop(game);
-                    player.revealCards("Callous Deceiver", cards, game);
+            if (card != null) {
-                    if (card != null && card.getCardType().contains(CardType.LAND)) {
+                cards.add(card);
-                            return true;
+                controller.revealCards(sourceObject.getIdName(), cards, game);
-                    }
+                if (card.getCardType().contains(CardType.LAND)) {
+                    game.addEffect(new BoostSourceEffect(1, 0, Duration.EndOfTurn), source);
+                    game.addEffect(new GainAbilitySourceEffect(FlyingAbility.getInstance(), Duration.EndOfTurn), source);
                 }
-        return false;
+            }
+            return true;
         }
-
+        return false;
-        @Override
-    public String getRule() {
-        return "{2}: Reveal the top card of your library. If it's a land card, {this} gets +1/+0 and gains flying until end of turn. Activate this ability only once each turn."; 
     }
 }

Mage.Sets/src/mage/sets/khansoftarkir/CleverImpersonator.java

@@ -52,7 +52,7 @@ public class CleverImpersonator extends CardImpl {
         this.power = new MageInt(0);
         this.toughness = new MageInt(0);
 
-        // You have may Clever Impersonator enter the battlefield as a copy of any nonland permanent on the battlefield.
+        // You may have Clever Impersonator enter the battlefield as a copy of any nonland permanent on the battlefield.
         this.addAbility(new SimpleStaticAbility(Zone.BATTLEFIELD,
                 new EntersBattlefieldEffect(new CopyPermanentEffect(new FilterNonlandPermanent()),
                         "You may have {this} enter the battlefield as a copy of any nonland permanent on the battlefield",

Mage.Sets/src/mage/sets/magic2015/SliverHive.java

@@ -33,10 +33,10 @@ import mage.MageInt;
 import mage.MageObject;
 import mage.Mana;
 import mage.abilities.Ability;
-import mage.abilities.common.SimpleActivatedAbility;
+import mage.abilities.condition.common.PermanentsOnTheBattlefieldCondition;
-import mage.abilities.costs.common.ControlPermanentCost;
 import mage.abilities.costs.common.TapSourceCost;
 import mage.abilities.costs.mana.GenericManaCost;
+import mage.abilities.decorator.ConditionalActivatedAbility;
 import mage.abilities.effects.common.CreateTokenEffect;
 import mage.abilities.mana.ColorlessManaAbility;
 import mage.abilities.mana.ConditionalAnyColorManaAbility;
@@ -58,6 +58,7 @@ import mage.game.permanent.token.Token;
 public class SliverHive extends CardImpl {
 
     private static final FilterControlledPermanent filter = new FilterControlledPermanent("Sliver");
+
     static {
         filter.add(new SubtypePredicate("Sliver"));
     }
@@ -73,9 +74,10 @@ public class SliverHive extends CardImpl {
         this.addAbility(new ConditionalAnyColorManaAbility(new TapSourceCost(), 1, new SliverHiveManaBuilder(), true));
 
         // {5}, {T}: Put a 1/1 colorless Sliver creature token onto the battlefield. Activate this ability only if you control a Sliver.
-        Ability ability = new SimpleActivatedAbility(Zone.BATTLEFIELD, new CreateTokenEffect(new SliverToken()), new TapSourceCost());
+        Ability ability = new ConditionalActivatedAbility(Zone.BATTLEFIELD, new CreateTokenEffect(new SliverToken()), new TapSourceCost(),
+                new PermanentsOnTheBattlefieldCondition(filter),
+                "{5}, {T}: Put a 1/1 colorless Sliver creature token onto the battlefield. Activate this ability only if you control a Sliver.");
         ability.addCost(new GenericManaCost(5));
-        ability.addCost(new ControlPermanentCost(filter));
         this.addAbility(ability);
     }