Cyclomatic复杂性巨大 - 克隆对象更好的方法？

Question

我的度量工具说copyTo（）方法的圈复数为44.这是非常巨大的。 如何使用更好更快的方法创建地址对象的克隆？注意：我没有可用的Cloneable接口（移动应用程序）。

这是班级：

class Address
{
    Address()
    {
        init();
    }

    String company1;
    String company2;
    String degree;
    String firstName;
    String lastName;
    String salutation;
    String toPerson;
    String poBox;
    String country;
    String postalCode;
    String place;
    String street;
    String telephone1;
    String telephone2;
    String mobilePhone;
    String privatePhone;
    String fax;
    String eMail;
    String homepage;
    String socialSecurityNumber;
    String bank1Name;
    String bank1BCN;
    String bank1AccountNr;
    String bank2Name;
    String bank2BCN;
    String bank2AccountNr;
    String free01Name;
    String free01Value;
    String free02Name;
    String free02Value;
    String free03Name;
    String free03Value;
    String free04Name;
    String free04Value;
    String free05Name;
    String free05Value;
    String comment;
    String cityCode;
    GpsPosition position;
    int recId;
    int recStatus;
    DateTime recCreated;
    String recCreatedBy;
    String recCreatedByProg;
    DateTime recChanged;
    String recChangedBy;
    String recChangedByProg;
    AddressPropertyUsage usage;

    /* Generates a duplicate of the Address object */
    Address clone()
    {
        Address clonedObject = new Address();

        copyTo(clonedObject);

        return clonedObject;
    }

    void copyTo(Address destination)
    {
        if (destination.usage == null)
            destination.usage = new AddressPropertyUsage(this.usage.value);
        else
            destination.usage.value = this.usage.value;

        destination.recId = this.recId;
        destination.recStatus = this.recStatus;
        destination.recChanged = this.recChanged.clone();

        if (this.recChangedBy == null)
            destination.recChangedBy = null;
        else
            destination.recChangedBy = this.recChangedBy.substring(0);

        if (this.recChangedByProg == null)
            destination.recChangedByProg = null;
        else
            destination.recChangedByProg = this.recChangedByProg.substring(0);

        destination.recCreated = this.recCreated.clone();

        if (this.recCreatedBy == null)
            destination.recCreatedBy = null;
        else
            destination.recCreatedBy = this.recCreatedBy.substring(0);

        if (this.recCreatedByProg == null)
            destination.recCreatedByProg = null;
        else
            destination.recCreatedByProg = this.recCreatedByProg.substring(0);

        if (this.company1 == null)
            destination.company1 = null;
        else
            destination.company1 = this.company1.substring(0);

        if (this.company2 == null)
            destination.company2 = null;
        else
            destination.company2 = this.company2.substring(0);

        if (this.degree == null)
            destination.degree = null;
        else
            destination.degree = this.degree.substring(0);

        if (this.firstName == null)
            destination.firstName = null;
        else
            destination.firstName = this.firstName.substring(0);

        if (this.lastName == null)
            destination.lastName = null;
        else
            destination.lastName = this.lastName.substring(0);

        if (this.street == null)
            destination.street = null;
        else
            destination.street = this.street.substring(0);

        if (this.postalCode == null)
            destination.postalCode = null;
        else
            destination.postalCode = this.postalCode.substring(0);

        if (this.place == null)
            destination.place = null;
        else
            destination.place = this.place.substring(0);

        if (this.country == null)
            destination.country = null;
        else
            destination.country = this.country.substring(0);

        if (this.poBox == null)
            destination.poBox = null;
        else
            destination.poBox = this.poBox.substring(0);

        if (this.telephone1 == null)
            destination.telephone1 = null;
        else
            destination.telephone1 = this.telephone1.substring(0);

        if (this.telephone2 == null)
            destination.telephone2 = null;
        else
            destination.telephone2 = this.telephone2.substring(0);

        if (this.mobilePhone == null)
            destination.mobilePhone = null;
        else
            destination.mobilePhone = this.mobilePhone.substring(0);

        if (this.fax == null)
            destination.fax = null;
        else
            destination.fax = this.fax.substring(0);

        if (this.eMail == null)
            destination.eMail = null;
        else
            destination.eMail = this.eMail.substring(0);

        if (this.homepage == null)
            destination.homepage = null;
        else
            destination.homepage = this.homepage.substring(0);

        if (this.salutation == null)
            destination.salutation = null;
        else
            destination.salutation = this.salutation.substring(0);

        if (this.toPerson == null)
            destination.toPerson = null;
        else
            destination.toPerson = this.toPerson.substring(0);

        if (this.privatePhone == null)
            destination.privatePhone = null;
        else
            destination.privatePhone = this.privatePhone.substring(0);

        if (this.comment == null)
            destination.comment = null;
        else
            destination.comment = this.comment.substring(0);

        if (this.cityCode == null)
            destination.cityCode = null;
        else
            destination.cityCode = this.cityCode.substring(0);

        this.position.copyTo(destination.position);

        if (this.bank1AccountNr == null)
            destination.bank1AccountNr = null;
        else
            destination.bank1AccountNr = this.bank1AccountNr.substring(0);

        if (this.bank1BCN == null)
            destination.bank1BCN = null;
        else
            destination.bank1BCN = this.bank1BCN.substring(0);

        if (this.bank1Name == null)
            destination.bank1Name = null;
        else
            destination.bank1Name = this.bank1Name.substring(0);

        if (this.bank2AccountNr == null)
            destination.bank2AccountNr = null;
        else
            destination.bank2AccountNr = this.bank2AccountNr.substring(0);

        if (this.bank2BCN == null)
            destination.bank2BCN = null;
        else
            destination.bank2BCN = this.bank2BCN.substring(0);

        if (this.bank2Name == null)
            destination.bank2Name = null;
        else
            destination.bank2Name = this.bank2Name.substring(0);

        if (this.socialSecurityNumber == null)
            destination.socialSecurityNumber = null;
        else
            destination.socialSecurityNumber = this.socialSecurityNumber.substring(0);

        if (this.free01Name == null)
            destination.free01Name = null;
        else
            destination.free01Name = this.free01Name.substring(0);

        if (this.free01Value == null)
            destination.free01Value = null;
        else
            destination.free01Value = this.free01Value.substring(0);

        if (this.free02Name == null)
            destination.free02Name = null;
        else
            destination.free02Name = this.free02Name.substring(0);

        if (this.free02Value == null)
            destination.free02Value = null;
        else
            destination.free02Value = this.free02Value.substring(0);

        if (this.free03Name == null)
            destination.free03Name = null;
        else
            destination.free03Name = this.free03Name.substring(0);

        if (this.free03Value == null)
            destination.free03Value = null;
        else
            destination.free03Value = this.free03Value.substring(0);

        if (this.free04Name == null)
            destination.free04Name = null;
        else
            destination.free04Name = this.free04Name.substring(0);

        if (this.free04Value == null)
            destination.free04Value = null;
        else
            destination.free04Value = this.free04Value.substring(0);

        if (this.free05Name == null)
            destination.free05Name = null;
        else
            destination.free05Name = this.free05Name.substring(0);

        if (this.free05Value == null)
            destination.free05Value = null;
        else
            destination.free05Value = this.free05Value.substring(0);
    }


    private void init()
    {
        this.company1 = StringHelper.emptyString;
        this.company2 = StringHelper.emptyString;
        this.degree = StringHelper.emptyString;
        this.firstName = StringHelper.emptyString;
        this.lastName = StringHelper.emptyString;
        this.salutation = StringHelper.emptyString;
        this.toPerson = StringHelper.emptyString;
        this.poBox = StringHelper.emptyString;
        this.country = StringHelper.emptyString;
        this.postalCode = StringHelper.emptyString;
        this.place = StringHelper.emptyString;
        this.street = StringHelper.emptyString;
        this.telephone1 = StringHelper.emptyString;
        this.telephone2 = StringHelper.emptyString;
        this.mobilePhone = StringHelper.emptyString;
        this.privatePhone = StringHelper.emptyString;
        this.fax = StringHelper.emptyString;
        this.eMail = StringHelper.emptyString;
        this.homepage = StringHelper.emptyString;
        this.socialSecurityNumber = StringHelper.emptyString;
        this.bank1Name = StringHelper.emptyString;
        this.bank1BCN = StringHelper.emptyString;
        this.bank1AccountNr = StringHelper.emptyString;
        this.bank2Name = StringHelper.emptyString;
        this.bank2BCN = StringHelper.emptyString;
        this.bank2AccountNr = StringHelper.emptyString;
        this.free01Name = StringHelper.emptyString;
        this.free01Value = StringHelper.emptyString;
        this.free02Name = StringHelper.emptyString;
        this.free02Value = StringHelper.emptyString;
        this.free03Name = StringHelper.emptyString;
        this.free03Value = StringHelper.emptyString;
        this.free04Name = StringHelper.emptyString;
        this.free04Value = StringHelper.emptyString;
        this.free05Name = StringHelper.emptyString;
        this.free05Value = StringHelper.emptyString;
        this.comment = StringHelper.emptyString;
        this.cityCode = StringHelper.emptyString;
        this.position = new GpsPosition();

        this.recId = 0;
        this.recStatus = -1;
        this.recCreated = DateTime.UNKNOWN_PC.clone();
        this.recCreatedBy = StringHelper.emptyString;
        this.recCreatedByProg = StringHelper.emptyString;
        this.recChanged = DateTime.UNKNOWN_PC.clone();
        this.recChangedBy = StringHelper.emptyString;
        this.recChangedByProg = StringHelper.emptyString;
        this.usage = new AddressPropertyUsage(AddressPropertyUsage.VERSION3_ALL);
    }

Answer 1

你有很多someString.substring(0)个东西（如果我计算正确的话，有43个出现）。由于字符串在Java中是不可变的，因此只需分配它们就足够了，因此对null的检查将是过时的。

Answer 2

您的Address类包含太多字段。理想情况下，您应该将对象拆分为许多小对象，例如：BankInfo，RecInfo，PhoneInfo，FreeValues等。然后让您的Address类包含变量这些对象。

Answer 3

您希望通过.substring(0)来电达到什么目的？

这创建了另一个具有与原始相同的底层char数组的对象，我可以看到它可能诱使您使用它。但是为什么你还需要另一个物体呢？字符串是不可变的，因此Address的两个实例都可以直接使用相同的String。

一旦这样做，你不需要任何if语句，并且可以直接赋值，例如：

// No need to create new instances of String...
//  if (this.recChangedBy == null)
//      destination.recChangedBy = null;
//  else
//      destination.recChangedBy = this.recChangedBy.substring(0);

// so above is replaced by:
destination.recChangedBy = this.recChangedBy;

Voila，大多数/所有条件已经消失，并且圈复杂度已经急剧下降。

---

（在另一个主题上，你的地址修改的频率是多少？我很想把它变成一个不可变的对象，并在构造函数中设置所有的值，这样恕我直言就可以更容易推理和使用它。与构建空地址相比。

也没有调用私有init方法的构造函数 - 只需将该方法的主体作为构造函数。

我不认为地址确实有44个字段，这看起来像God Object。如果Address类仅代表地址，银行详细信息转到Account类，最后的更改详细信息显示在AuditDetails类中，则您的代码可能会更清晰，等等。）

Answer 4

我同意其他所有人说你不应该试图复制字符串，并且不这样做可以让你摆脱条件。但值得补充的是：如果 需要进行条件复制 - 例如，如果这些东西不是字符串而是其他类型的对象 - 那么你最好考虑因素重复的逻辑：

String copyUnlessNull(String s) {
  if (s==null) return null;
  return s.substring(0);
}

void copyTo(Address destination) {
  // ...
  destination.recChangedBy     = copyUnlessNull(this.recChangedBy);
  destination.recChangedByProg = copyUnlessNull(this.recChangedByProg);
  // ...
}

为了避免疑问，上面的不在这种特殊情况下是正确的解决方案 - 你根本不应该打扰substring（）的东西，然后你就不需要了条件逻辑 - 但是每当你发现自己一遍又一遍地编写相同的代码时，你应该寻找一种方法来只写一次并重复使用它。