过滤器模式（Filter Pattern）或标准模式（Criteria Pattern）是一种设计模式，这种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。这种类型的设计模式属于结构型模式，它结合多个标准来获得单一标准。
下面创建了CriteriaMale、CriteriaFemale、CriteriaSingle、AndCriteria、OrCriteria都实现了Criteria接口并重写了meetCriteria方法，在Client中可以根据需要过滤出所需要的数据
1.创建Criteria接口和Person实体类
package com.design.demo.filter;
/**
* @author: GuanBin
* @date: Created in 下午11:11 2019/8/18
*/
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 void setName(String name) {
this.name = name;
}
public String getGender() {
return gender;
}
public void setGender(String gender) {
this.gender = gender;
}
public String getMaritalStatus() {
return maritalStatus;
}
public void setMaritalStatus(String maritalStatus) {
this.maritalStatus = maritalStatus;
}
}
package com.design.demo.filter;
import java.util.List;
/**
* @author: GuanBin
* @date: Created in 下午11:14 2019/8/18
*/
public interface Criteria {
public List<Person> meetCriteria(List<Person> personList);
}
2.创建CriteriaMale
package com.design.demo.filter;
import java.util.ArrayList;
import java.util.List;
/**
* @author: GuanBin
* @date: Created in 下午11:15 2019/8/18
*/
public class CriteriaMale implements Criteria {
@Override
public List<Person> meetCriteria(List<Person> personList) {
ArrayList<Person> malePersons = new ArrayList<>();
for (Person person : personList) {
if (person.getGender().equalsIgnoreCase("MALE")) {
malePersons.add(person);
}
}
return malePersons;
}
}
3.创建CriteriaFemale
package com.design.demo.filter;
import java.util.ArrayList;
import java.util.List;
/**
* @author: GuanBin
* @date: Created in 下午11:15 2019/8/18
*/
public class CriteriaFemale implements Criteria {
@Override
public List<Person> meetCriteria(List<Person> personList) {
ArrayList<Person> femalePersons = new ArrayList<>();
for (Person person : personList) {
if (person.getGender().equalsIgnoreCase("FEMALE")) {
femalePersons.add(person);
}
}
return femalePersons;
}
}
4.创建CriteriaSingle
package com.design.demo.filter;
import java.util.ArrayList;
import java.util.List;
/**
* @author: GuanBin
* @date: Created in 下午11:15 2019/8/18
*/
public class CriteriaSingle implements Criteria {
@Override
public List<Person> meetCriteria(List<Person> personList) {
ArrayList<Person> singlePersons = new ArrayList<>();
for (Person person : personList) {
if (person.getMaritalStatus().equalsIgnoreCase("SINGLE")) {
singlePersons.add(person);
}
}
return singlePersons;
}
}
5.创建AndCriteria
package com.design.demo.filter;
import java.util.ArrayList;
import java.util.List;
/**
* @author: GuanBin
* @date: Created in 下午11:15 2019/8/18
*/
public class AndCriteria implements Criteria {
private Criteria criteria;
private Criteria otherCriteria;
public AndCriteria(Criteria criteria, Criteria otherCriteria) {
this.criteria = criteria;
this.otherCriteria = otherCriteria;
}
@Override
public List<Person> meetCriteria(List<Person> personList) {
List<Person> people = criteria.meetCriteria(personList);
return otherCriteria.meetCriteria(people);
}
}
6.创建OrCriteria
package com.design.demo.filter;
import java.util.List;
/**
* @author: GuanBin
* @date: Created in 下午11:15 2019/8/18
*/
public class OrCriteria implements Criteria {
private Criteria criteria;
private Criteria otherCriteria;
public OrCriteria(Criteria criteria, Criteria otherCriteria) {
this.criteria = criteria;
this.otherCriteria = otherCriteria;
}
@Override
public List<Person> meetCriteria(List<Person> personList) {
List<Person> people = criteria.meetCriteria(personList);
List<Person> otherPeople = otherCriteria.meetCriteria(people);
otherPeople.stream().forEach(person -> {
if(!people.contains(person)){
people.add(person);
}
});
return people;
}
}
7.创建Client类
package com.design.demo.filter;
import java.util.ArrayList;
import java.util.List;
/**
* @author: GuanBin
* @date: Created in 下午11:27 2019/8/18
*/
public class Client {
public static void main(String[] args) {
List<Person> people = new ArrayList<>();
people.add(new Person("lisi","Male","Single"));
people.add(new Person("zhangsan","Male","Single"));
people.add(new Person("wangwu","Female","Married"));
people.add(new Person("zhangliu","Male","Married"));
people.add(new Person("wangsi","Female","Single"));
CriteriaMale criteriaMale = new CriteriaMale();
CriteriaFemale criteriaFemale = new CriteriaFemale();
CriteriaSingle criteriaSingle = new CriteriaSingle();
//即为女士又是单身的人
AndCriteria andCriteria = new AndCriteria(criteriaMale,criteriaSingle);
//男士和单身的人
OrCriteria orCriteria = new OrCriteria(criteriaFemale,criteriaSingle);
System.out.println("-----Male");
printPersons(criteriaMale.meetCriteria(people));
System.out.println("-----Female");
printPersons(criteriaFemale.meetCriteria(people));
System.out.println("-----Single");
printPersons(criteriaSingle.meetCriteria(people));
System.out.println("-----Male and Single");
printPersons(andCriteria.meetCriteria(people));
System.out.println("-----Femal or Single");
printPersons(orCriteria.meetCriteria(people));
}
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()
+" ]");
}
}
}