NBA之过滤器模式

Design Pattern:

Filter pattern or Criteria pattern is a design pattern that enables developers to filter a set of objects using different criteria and chaining them in a decoupled way through logical operations. 模式：过滤器模式使用criteria用来过滤一系列对象,criteria用来解耦

故事场景：根据2017年勇士队季后赛投篮表现,我要看下命中率超过40%的球员

球员

  public class Person {

      public Person(double rate, String name) {
          this.rate = rate;
          this.name = name;
      }
      //投篮命中率
      private double rate;
      //curry durant
      private String name;

      public double getRate() {
          return rate;
      }

      public void setRate(double rate) {
          this.rate = rate;
      }

      public String getName() {
          return name;
      }

      public void setName(String name) {
          this.name = name;
      }
  }

过滤器

  public interface Criteria {

      public List<Person> list(List<Person> peopleList);
  }

  public class ShootCriteria implements Criteria {

      private final double DEFAULT_RATE = 0.4;

      @Override
      public List<Person> list(List<Person> peopleList) {
          if (peopleList == null || peopleList.size() == 0) {
              return new ArrayList<>();
          }
          List<Person> personList = new ArrayList<>();
          for (Person person : peopleList) {
              if (person.getRate() <= DEFAULT_RATE){
                  continue;
              }
              personList.add(person);
          }
          return personList;
      }
  }

##### 实验的开始
``` java
    public class CriteriaDemo {


        public static void main(String[] args) {

            List<Person> personList = new ArrayList<>();
            personList.add(new Person(0.8,"durant"));
            personList.add(new Person(0.9,"curry"));
            Criteria criteria = new ShootCriteria();
            List<Person> newList = criteria.list(personList);
            if (newList.size() != 0){
                for (Person person: newList){
                    System.out.println(person.getName()+",");
                }
            }
        }
    }

结果