How to use

LockedInDynamicValue

in

mage.abilities.dynamicvalue

@Override
public LockedInDynamicValue copy() {
  return new LockedInDynamicValue(this, true);
}

public GideonChampionOfJustice(UUID ownerId, CardSetInfo setInfo) {
  super(ownerId,setInfo,new CardType[]{CardType.PLANESWALKER},"{2}{W}{W}");
  this.addSuperType(SuperType.LEGENDARY);
  this.subtype.add(SubType.GIDEON);
  this.addAbility(new PlaneswalkerEntersWithLoyaltyCountersAbility(4));
  // +1: Put a loyalty counter on Gideon, Champion of Justice for each creature target opponent controls.
  LoyaltyAbility ability1 = new LoyaltyAbility(
      new AddCountersSourceEffect(CounterType.LOYALTY.createInstance(0), new PermanentsTargetOpponentControlsCount(new FilterCreaturePermanent()), true), 1);
  ability1.addTarget(new TargetOpponent());
  this.addAbility(ability1);
  // 0: Until end of turn, Gideon becomes an indestructible Human Soldier creature with power and toughness each equal to the number of loyalty counters on him. He's still a planeswalker. Prevent all damage that would be dealt to him this turn.
  LockedInDynamicValue loyaltyCount = new LockedInDynamicValue(new CountersSourceCount(CounterType.LOYALTY));
  LoyaltyAbility ability2 = new LoyaltyAbility(new BecomesCreatureSourceEffect(
      new GideonChampionOfJusticeToken(), "planeswalker", Duration.EndOfTurn, false, false, loyaltyCount, loyaltyCount), 0);
  ability2.addEffect(new PreventAllDamageToSourceEffect(Duration.EndOfTurn));
  this.addAbility(ability2);
  // -15: Exile all other permanents.
  this.addAbility(new LoyaltyAbility(new GideonExileAllOtherPermanentsEffect(), -15));
}