UML中类图的代码实现

Question

更新 3

下面的图表（来自 Eric 的 ddd 书 p195）中的符号（单线、带星形的菱形和箭头）是什么意思：

任何用于说明的代码示例都将不胜感激。

Answer 1

菱形是组合（也称为聚合）或has-a 关系。箭头是继承，或is-a 关系。该行是一个协会。这就引出了一个问题：组合和关联之间有什么区别。答案是组合更强大，通常拥有另一个对象。如果主对象被销毁，它也会销毁它的组合对象，但不会销毁它的关联对象。

在您的示例中，Facility 包含 (has-a) LoanInvestment，而 LoanInvestment 继承自 (is-a) Investment

这是对class diagrams using UML的精彩描述。

这是一个 c++ 代码示例，我不太了解 c#，我可能会把它搞砸:)

class Facility
{
public:
    Facility() : loan_(NULL) {}

    // Association, weaker than Composition, wont be destroyed with this class
    void setLoan(Loan *loan) { loan_ = loan; } 

private:
    // Composition, owned by this class and will be destroyed with this class
    // Defined like this, its a 1 to 1 relationship
    LoanInvestment loanInvestment_;
    // OR
    // One of the following 2 definitions for a multiplicity relation
    // The list is simpler, whereas the map would allow faster searches
    //std::list<LoanInvestment> loanInvList_;
    //std::map<LoanInvestment> loanInvMap_;

    Loan *loan_:
    // define attributes here: limit
};

class Loan
{
public:
    // define attributes here: amount
    // define methods here: increase(), decrease()
private:
    // 1 to 1 relationship, could consider multiplicity with a list or map
    LoanInvestment loanInvestment_;
};

class Investment
{
    // define attributes here: investor, percentage
};

class LoanInvestment : public LoanInvestment
{
    // define attributes here
};