所以我对这个游戏还比较陌生。我有一个java类“family”，我想在其中实现一个boolean方法，告诉我x是y的兄弟（true还是false）等等。

public class Family {

  private final Gender gender; // enum
  private final String name;
  private Family parent;
  private Family firstChild;
  private Family seccondChild;
  private Family thirdChild;

  public Family (final String name, final Gender gender) {
    this.name = name;
    this.gender = gender;
  }

  public String getName() {
    return name;
  }

  public Gender getGender() {
    return gender;
  }

  public Family getThirdChild() {
    return thirdChild;
  }

  public void setThirdChild(Family thirdChild) {
    this.thirdChild = thirdChild;
  }

  public void setSeccondChild(Family seccondChild) {
    this.seccondChild = seccondChild;
  }

  public Family getSeccondChild() {
    return seccondChild;
  }

  public Family getFirstChild() {
    return firstChild;
  }

  public void setFirstChild(Family firstChild) {
    this.firstChild = firstChild;
  }

  public Family getParent() {
    return parent;
  }

  public void setParent(Family parent) {
    this.parent = parent;
  }

  // So here is my problem I don't know how to show, that two children are siblings or not

public boolean isTheSiblingOf(Family x) {
    if ( ) {    // If  y is sibling of x return true.. How?? 
      return true;
    }
    return false;
  }

  public String toString() {
    return "Family: " + name;
  }

}

这是我的对象的另一个类。如你所见，我只提到母亲。我需要父亲做别的事，但不是现在。

Family theo = new Family("Theo", Gender.M); // Father
Family clara = new Family ("Clara", Gender.F); // Mother

Family john = new Family("John", Gender.M);
john.setParent(clara); // I'm only choosing one parent
clara.setFirstChild(john);

Family rachel = new Family("Rachel", Gender.F);
rachel.setParent(clara);
clara.setSeccondChild(rachel);

Family jennifer = new Family("Jennifer", Gender.F);
jennifer.setParent(clara);
clara.setThirdChild(jennifer);