Question

我需要根据以下一个或多个搜索条件搜索对象集合（例如，预订）。我打算使用过滤模式来实现这一点。

搜索选项：名字，姓氏，电话，电子邮件

要求是 - 如果用户仅指定了snname过滤器，则仅使用firstname进行过滤。如果用户同时指定了firstname和phone，请同时使用（和条件）进行过滤。如果指定了所有4个选项，则使用全部4.

我为所有4个搜索条件创建了类。我对如何使用它有疑问。例如，

ISearchCriteria searchCriteria;

   if(firstName != null)
   {
            searchCriteria= new FirstNameSearchCriteria(CurrentClient);
   }

   if(lastName!= null)
   {
           //what do I do here? I have an AndCriteria class which accepts two ISearchCriteria objects. How do I use it?
   }

处理此搜索方案的正确方法是什么？

Answer 1

您应该使用拦截过滤器模式来设计问题陈述的解决方案。

以下是使用截取过滤器模式的代码：

public class Person
{

    public String FirstName { get; set; }
    public String LastName { get; set; }
    public String Phone { get; set; }
    public String Email { get; set; }
}

public interface ICriteria
{
         List<Person> MeetCriteria(List<Person> persons);
}

  public class CriteriaFirstName : ICriteria
    {
        private string searchCriteria;
        public CriteriaFirstName(string searchCriteria)
        {
            this.searchCriteria = searchCriteria;
        }
        public List<Person> MeetCriteria(List<Person> persons)
        {
            List<Person> personsData = new List<Person>();
            foreach (var item in persons)
            {
                if (item.FirstName.ToUpper().Equals(searchCriteria.ToUpper()))
                {
                    personsData.Add(item);
                }
            }

            return personsData;
        }


    public class CriteriaLastName : ICriteria
    {
        private string searchCriteria;
        public CriteriaLastName(string searchCriteria)
        {
            this.searchCriteria = searchCriteria;
        }

        public List<Person> MeetCriteria(List<Person> persons)
        {
            List<Person> personsData = new List<Person>();
            foreach (var item in persons)
            {
                if (item.LastName.ToUpper().Equals(searchCriteria.ToUpper()))
                {
                    personsData.Add(item);
                }
            }

            return personsData;
        }
    }

 public class CriteriaLastPhone : ICriteria
    {
        private string searchCriteria;
        CriteriaLastPhone(string searchCriteria)
        {
            this.searchCriteria = searchCriteria;
        }

        public List<Person> MeetCriteria(List<Person> persons)
        {
            List<Person> personsData = new List<Person>();
            foreach (var item in persons)
            {
                if (item.Phone.ToUpper().Equals(searchCriteria.ToUpper()))
                {
                    personsData.Add(item);
                }
            }

            return personsData;
        }
    }

   public class CriteriaEmail : ICriteria
    {
        private string searchCriteria;
        public CriteriaEmail(string searchCriteria)
        {
            this.searchCriteria = searchCriteria;
        }
        public List<Person> MeetCriteria(List<Person> persons)
        {
            List<Person> personsData = new List<Person>();
            foreach (var item in persons)
            {
                if (item.Email.ToUpper().Equals(searchCriteria.ToUpper()))
                {
                    personsData.Add(item);
                }
            }

            return personsData;
        }
    }


public class AndCriteria : ICriteria
{
    private ICriteria criteria;
    private ICriteria otherCriteria;

    public AndCriteria(ICriteria criteria, ICriteria otherCriteria)
    {
        this.criteria = criteria;
        this.otherCriteria = otherCriteria;
    }

    public List<Person> MeetCriteria(List<Person> persons)
    {
        List<Person> firstCriteriaPersons = criteria.MeetCriteria(persons);
        return otherCriteria.MeetCriteria(firstCriteriaPersons);
    }
}

public class OrCriteria : ICriteria
{
    private ICriteria criteria;
    private ICriteria otherCriteria;

    public OrCriteria(ICriteria criteria, ICriteria otherCriteria)
    {
        this.criteria = criteria;
        this.otherCriteria = otherCriteria;
    }

    public List<Person> MeetCriteria(List<Person> persons)
    {
        List<Person> firstCriteriaItems = criteria.MeetCriteria(persons);
        List<Person> otherCriteriaItems = otherCriteria.MeetCriteria(persons);

        foreach (var otherItems in otherCriteriaItems)
        {
            if (!firstCriteriaItems.Contains(otherItems))
            {
                firstCriteriaItems.Add(otherItems);
            }
        }

        return firstCriteriaItems;
    }

}

驱动程序代码：

class Program
{
    static void Main(string[] args)
    {
        List<Person> persons = new List<Person>();

        persons.Add(new Person { FirstName = "Robert", LastName = "kerry", Phone = "1234", Email = "cddd@xyz.com"});
        persons.Add(new Person { FirstName = "Robert", LastName = "Sam", Phone = "1234", Email = "sam@xyz.com" });
        persons.Add(new Person { FirstName = "Jon", LastName = "Kam", Phone = "1234", Email = "john@xyz.com" });

        Console.WriteLine("---Search by First and Last Name----");
        ICriteria firstName = new CriteriaFirstName("Robert");
        ICriteria lastName = new CriteriaLastName("Kerry");
        ICriteria fullName = new AndCriteria(firstName, lastName);
        var searchedData = fullName.MeetCriteria(persons);

        //Search by First and last name (And criteria)
        foreach (var person in searchedData)
        {
            Console.WriteLine(person.FirstName);
            Console.WriteLine(person.LastName);
            Console.WriteLine(person.Phone);
        }

        //Search by first name and email. (And Criteria)
        firstName = new CriteriaFirstName("Robert");
        var email = new CriteriaEmail("sam@xyz.com");
        fullName = new AndCriteria(firstName, email);
        searchedData = fullName.MeetCriteria(persons);
        foreach (var person in searchedData)
        {
            Console.WriteLine(person.FirstName);
            Console.WriteLine(person.LastName);
            Console.WriteLine(person.Phone);
        }

        Console.WriteLine("---Search by First Name Only----");
        firstName = new CriteriaFirstName("Robert");
        searchedData = firstName.MeetCriteria(persons);
        foreach (var person in searchedData)
        {
            Console.WriteLine(person.FirstName);
            Console.WriteLine(person.LastName);
            Console.WriteLine(person.Phone);
        }

        Console.WriteLine("---Search by First Name or email ----");
        //Search by first name . (or Criteria)
        firstName = new CriteriaFirstName("Robert");
        email = new CriteriaEmail("john@xyz.com");
        fullName = new OrCriteria(firstName, email);
        searchedData = fullName.MeetCriteria(persons);
        foreach (var person in searchedData)
        {
            Console.WriteLine(person.FirstName);
            Console.WriteLine(person.LastName);
            Console.WriteLine(person.Phone);
        }

        Console.ReadKey();
    }
}

使用过滤器设计模式动态创建过滤条件

1 个答案: