package io.atlassian.fugue.optic.law;
   
   import io.atlassian.fugue.law.IsEq;
   import io.atlassian.fugue.optic.PSetter;
   
   import java.util.function.Function;
   
   import static io.atlassian.fugue.law.IsEq.isEq;
   
  public final class SetterLaws<S, A> {
  
    private final PSetter<S, S, A, A> setter;
  
    public SetterLaws(PSetter<S, S, A, A> setter) {
      this.setter = setter;
    }
  
    /**
     * set idempotent
     */
    public IsEq<S> setIdempotent(S s, A a) {
      return isEq(setter.set(a).apply(setter.set(a).apply(s)), setter.set(a).apply(s));
    }
  
    /**
     * modify id = id
     */
    public IsEq<S> modifyIdentity(S s) {
      return isEq(setter.modify(Function.<A> identity()).apply(s), s);
    }
  
  }