this.color.setBlack(true);
// As long as you control exactly one creature, that creature gets +3/+1 and has lifelink.
ContinuousEffect boostEffect = new BoostControlledEffect(3, 1, Duration.WhileOnBattlefield);
Effect effect = new ConditionalContinousEffect(boostEffect, new OneControlledCreatureCondition(), rule);
Ability ability = new SimpleStaticAbility(Zone.BATTLEFIELD, effect);
ContinuousEffect lifelinkEffect = new GainAbilityControlledEffect(LifelinkAbility.getInstance(), Duration.WhileOnBattlefield);
effect = new ConditionalContinousEffect(lifelinkEffect, new OneControlledCreatureCondition(), "and has lifelink");
ability.addEffect(effect);
this.addAbility(ability);