c# - 使用带有构建器模式的流畅界面

Question

我试图通过创建下面的 person builder 对象来理解流畅的构建器模式。我已经按照我想使用的方式编写了代码，但是在实现它时遇到了问题。我的问题如下:

1. 当调用 HavingJob() 时，这应该创建一个新的作业，然后可以仅使用作业的适用方法进行配置，并最终添加到 Jobs 集合中人。感觉应该返回它，以便可以调用其他流畅的工作方法。不确定如何在允许在该级别及更高级别进行链接的同时实现它。
2. 在实现 IJobBuilder 方法时，我无法访问它们在 HavingJob() 方法中创建的特定作业，因为我需要返回 IJobBuilder 将流畅的方法限制为仅与作业相关的方法。 HavingJob() 的诀窍是什么，以便那些特定的作业方法可以在特定的作业上运行，同时仍然允许链接？
3. 一旦我沿着以 IJobBuilder 结尾的流畅路径前进，我就不能再调用 Build() 或 HavingJob() 来添加额外的工作。对此问题的答案是否是拥有一个继承自 PersonBuilder 的 IJobBuilder 的单独实现？

    public class Person
    {
        public string Name { get; set; }
        public List<Job> Jobs { get; set; }
        public List<Phone> Phones { get; set; }
    }

    public class Phone
    {
        public string Number { get; set; }
        public string Usage { get; set; }
    }

    public class Job
    {
        public string CompanyName { get; set; }
        public int Salary { get; set; }
    }

    class Program
    {
        static void Main(string[] args)
        {
            var p = PersonBuilder
                .Create()
                    .WithName("My Name")
                    .HavingPhone("222-222-2222")
                        .WithUsage("CELL")
                    .HavingJob()
                        .WithCompanyName("First Company")
                        .WithSalary(100)
                    .HavingJob()
                        .WithCompanyName("Second Company")
                        .WithSalary(200)
                .Build();

            Console.WriteLine(JsonConvert.SerializeObject(p));
        }
    }

    public class PersonBuilder : IJobBuilder
    {
        protected Person Person;
        public PersonBuilder() { Person = new Person(); }
        public static PersonBuilder Create() => new PersonBuilder();
        public PersonBuilder WithName(string name)
        {
            Person.Name = name;
            return this;
        }

        public PersonBuilder HavingPhone(string phoneNumber)
        {
            // Need instance of phone
            return this;
        }

        public PersonBuilder WithUsage(string phoneUsage)
        {
            // Need instance of phone
            return this;
        }

        public IJobBuilder HavingJob()
        {
            // Need to create a job here and return it so that IJobBuilder methods work on specific instance right?
            return this;
        }

        public Person Build() => Person;

        public IJobBuilder WithCompanyName(string companyName)
        {
            // How do I set the company name if I don't have the job instance here
            job.CompanyName = companyName;
            return this;
        }

        public IJobBuilder WithSalary(int amount)
        {
            // How do I set the salary if I don't have a specific job instance here
            job.Salary = amount;
            return this;
        }
    }

    public interface IJobBuilder
    {
        IJobBuilder WithCompanyName(string companyName);
        IJobBuilder WithSalary(int salary);
    }

Answer 1

单一职责原则 (SRP) 和关注点分离 (SoC)

Job Builder 应该负责构建 Job

public interface IJobBuilder {
    IJobBuilder WithCompanyName(string companyName);
    IJobBuilder WithSalary(int salary);
}

public class JobBuilder : IJobBuilder {
    private readonly Job job;

    public JobBuilder() {
        job = new Job();
    }

    public IJobBuilder WithCompanyName(string companyName) {
        job.CompanyName = companyName;
        return this;
    }

    public IJobBuilder WithSalary(int amount) {
        job.Salary = amount;
        return this;
    }

    internal Job Build() => job;
}

Person Builder 应该负责构建 Person。

public class PersonBuilder {
    protected Person Person;
    
    private PersonBuilder() { Person = new Person(); }

    public static PersonBuilder Create() => new PersonBuilder();

    public PersonBuilder WithName(string name) {
        Person.Name = name;
        return this;
    }

    public PersonBuilder HavingJob(Action<IJobBuilder> configure) {
        var builder = new JobBuilder();
        configure(builder);
        Person.Jobs.Add(builder.Build());
        return this;
    }

    public Person Build() => Person;

}

在上面的构建器中，它将工作的构建委托(delegate)给其负责的构建器。

这导致以下重构

class Program {
    static void Main(string[] args) {
        var p = PersonBuilder
            .Create()
                .WithName("My Name")
                .HavingJob(builder => builder
                    .WithCompanyName("First Company")
                    .WithSalary(100)
                )
                .HavingJob(builder => builder
                    .WithCompanyName("Second Company")
                    .WithSalary(200)
                )
            .Build();

        Console.WriteLine(JsonConvert.SerializeObject(p));
    }
}