设计模式-过滤器模式

过滤器模式简介

定义：是一种结构性模式，允许开发人员使用不同的标准来过滤一组对象，通过逻辑运算以解耦的方式把它们连接起来

目标：将传递过来的数据进行分类处理

实现

代码：

/**实体类**/
public class Person {
    private String name;
    private String gender;
    private String maritalStatus;
     
    public Person(String name,String gender,String maritalStatus){
        this.name = name;
        this.gender = gender;
        this.maritalStatus = maritalStatus;    
     }
     
     public String getName() {
        return name;
     }
     public String getGender() {
        return gender;
     }
     public String getMaritalStatus() {
        return maritalStatus;
     }
}

/**过滤接口**/
public interface Filter {
    public List<Person> meetCriteria(List<Person> persons);
}

/**具体过滤类1**/
public class FilterMale implements Filter{

    public List<Person> meetCriteria(List<Person> persons) {
        // TODO Auto-generated method stub
        List<Person> malePersons = new ArrayList<Person>(); 
          for (Person person : persons) {
             if(person.getGender().equalsIgnoreCase("MALE")){
                malePersons.add(person);
             }
          }
          return malePersons;
    }

}

/**具体过滤类2**/
public class FilterFemale implements Filter{

    public List<Person> meetCriteria(List<Person> persons) {
        // TODO Auto-generated method stub
        List<Person> malePersons = new ArrayList<Person>(); 
          for (Person person : persons) {
             if(person.getGender().equalsIgnoreCase("FEMALE")){
                malePersons.add(person);
             }
          }
          return malePersons;
    }

}

/**具体过滤类3**/
public class FilterSingle implements Filter{

    public List<Person> meetCriteria(List<Person> persons) {
        // TODO Auto-generated method stub
        List<Person> malePersons = new ArrayList<Person>(); 
          for (Person person : persons) {
             if(person.getGender().equalsIgnoreCase("SINGLE")){
                malePersons.add(person);
             }
          }
          return malePersons;
    }

}

/**测试类**/
public class App {
    public static void printPersons(List<Person> persons){
          for (Person person : persons) {
             System.out.println("Person : [ Name : " + person.getName() 
                +", Gender : " + person.getGender() 
                +", Marital Status : " + person.getMaritalStatus()
                +" ]");
          }
    }
    public static void main( String[] args ){
        List<Person> persons = new ArrayList<Person>();
        persons.add(new Person("Robert","Male", "Single"));
        persons.add(new Person("John","Male", "Married"));
        persons.add(new Person("Laura","Female", "Married"));
        persons.add(new Person("Diana","Female", "Single"));
        persons.add(new Person("Mike","Male", "Single"));
        persons.add(new Person("Bobby","SINGLE", "Single"));
        
        Filter male = new FilterMale();
        Filter female = new FilterFemale();
        Filter single = new FilterSingle();
   
        System.out.println("Males: ");
        printPersons(male.meetCriteria(persons));
   
        System.out.println("
Females: ");
        printPersons(female.meetCriteria(persons));
        
        System.out.println("
Single: ");
        printPersons(single.meetCriteria(persons));
    }
    
    
}

测试结果：
Males: 
Person : [ Name : Robert, Gender : Male, Marital Status : Single ]
Person : [ Name : John, Gender : Male, Marital Status : Married ]
Person : [ Name : Mike, Gender : Male, Marital Status : Single ]

Females: 
Person : [ Name : Laura, Gender : Female, Marital Status : Married ]
Person : [ Name : Diana, Gender : Female, Marital Status : Single ]

Single: 
Person : [ Name : Bobby, Gender : SINGLE, Marital Status : Single ]