java 设计模式之过滤器模式(Filter)
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1.概述:
允许开发人员根据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他们连接起来
2.实际场景
定义一个Person类，拥有姓名(name)、性别(gender)、婚姻状况(marital)三个属性。在实际的系统运用中需要对这三个属性进行不同条件的筛选 比如:
1.获取所有的男生信息
2.获取所有的单身人信息
3.获取所有的已婚人信息
4.获取所有的单身男生信息
5.获取所有的已婚女生信息
3.示例代码
Person类
package com.ven.domain;
/**
* perison
* @author xiaowen
*
*/
public class Person
//姓名
private String name;
//性别:MALE FEMALE
private String gender;
//婚姻状况:已婚或未婚
private String marital;
public Person(String name, String gender, String marital)
this.name = name;
this.gender = gender;
this.marital = marital;
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 getMarital()
return marital;
public void setMarital(String marital)
this.marital = marital;
package com.ven.service;
import java.util.List;
import com.ven.domain.Person;
/**
* 过滤器接口
* @author xiaowen
*
*/
public interface IFilter
List<Person> filter(List<Person> persons);
package com.ven.service;
import java.util.ArrayList;
import java.util.List;
import java.util.stream.Collectors;
import com.ven.consist.CommonConsist;
import com.ven.domain.Person;
/**
* 男生过滤器
* @author xiaowen
*
*/
public class MaleFilter implements IFilter
@Override
public List<Person> filter(List<Person> persons)
List<Person> result = new ArrayList<>();
List<Person> convertResult = persons.stream().filter(person->person.getGender().equals(CommonConsist.GENDER_MALE)).collect(Collectors.toList());
convertResult.forEach(p->result.add(p););
return result;
package com.ven.service;
import java.util.ArrayList;
import java.util.List;
import java.util.stream.Collectors;
import com.ven.consist.CommonConsist;
import com.ven.domain.Person;
/**
* 单身过滤器
* @author xiaowen
*
*/
public class SingleFilter implements IFilter
@Override
public List<Person> filter(List<Person> persons)
List<Person> result = new ArrayList<>();
List<Person> convertResult = persons.stream().filter(person->person.getMarital().equals(CommonConsist.MARITAL_SINGLE)).collect(Collectors.toList());
convertResult.forEach(p->result.add(p););
return result;
package com.ven.service;
import java.util.ArrayList;
import java.util.List;
import java.util.stream.Collectors;
import com.ven.consist.CommonConsist;
import com.ven.domain.Person;
/**
* 单身过滤器
* @author xiaowen
*
*/
public class MarryFilter implements IFilter
@Override
public List<Person> filter(List<Person> persons)
List<Person> result = new ArrayList<>();
List<Person> convertResult = persons.stream().filter(person->person.getMarital().equals(CommonConsist.MARITAL_MARRIED)).collect(Collectors.toList());
convertResult.forEach(p->result.add(p););
return result;
package com.ven.service;
import java.util.List;
import com.ven.domain.Person;
/**
* 处理并且逻辑的组合条件过滤器
* @author xiaowen
*
*/
public class FilterAnd implements IFilter
private IFilter filter;
private IFilter otherFilter;
public FilterAnd(IFilter filter, IFilter otherFilter)
this.filter = filter;
this.otherFilter = otherFilter;
@Override
public List<Person> filter(List<Person> persons)
List<Person> personList = filter.filter(persons);
List<Person> result = otherFilter.filter(personList);
return result;
package com.ven.consist;
/**
* 接口常量类
* @author xiaowen
*
*/
public interface CommonConsist
static final String GENDER_MALE="MALE";
static final String GENDER_FEMALE="FEMALE";
static final String MARITAL_SINGLE="SINGLE";
static final String MARITAL_MARRIED="MARRIED";
package com.ven.test;
import java.util.ArrayList;
import java.util.List;
import com.ven.domain.Person;
import com.ven.service.FilterAnd;
import com.ven.service.MaleFilter;
import com.ven.service.MarryFilter;
import com.ven.service.SingleFilter;
/**
* 过滤器模式(Filter)测试
* @author xiaowen
*
*/
public class Test02
public static void main(String[] args)
// 初始化数据
List<Person> persons = new ArrayList<>();
persons.add(new Person("霍一", "FEMALE", "MARRIED"));
persons.add(new Person("邓二", "MALE", "MARRIED"));
persons.add(new Person("张三", "MALE", "SINGLE"));
persons.add(new Person("李四", "FEMALE", "MARRIED"));
persons.add(new Person("王五", "MALE", "SINGLE"));
persons.add(new Person("赵六", "FEMALE", "SINGLE"));
persons.add(new Person("孙七", "MALE", "SINGLE"));
persons.add(new Person("罗八", "MALE", "MARRIED"));
persons.add(new Person("刘九", "FEMALE", "SINGLE"));
persons.add(new Person("史十", "FEMALE", "SINGLE"));
System.out.println("---------------获取所有的男性信息------------------");
List<Person> maleList = new MaleFilter().filter(persons);
maleList.forEach(male->
System.out.println(male.getName()+"-"+male.getGender()+"-"+male.getMarital());
);
System.out.println("---------------获取所有单身------------------");
List<Person> singleList = new SingleFilter().filter(persons);
singleList.forEach(single->
System.out.println(single.getName()+"-"+single.getGender()+"-"+single.getMarital());
);
System.out.println("--------------------所有单身的男性-------------------");
List<Person> singleAndMale = new FilterAnd(new MaleFilter(), new SingleFilter()).filter(persons);
singleAndMale.forEach(result->
System.out.println(result.getName()+"-"+result.getGender()+"-"+result.getMarital());
);
System.out.println("--------------------所有已婚的男性-------------------");
List<Person> marryList = new FilterAnd(new MaleFilter(), new MarryFilter()).filter(persons);
marryList.forEach(marrayAndMale->
System.out.println(marrayAndMale.getName()+"-"+marrayAndMale.getGender()+"-"+marrayAndMale.getMarital());
);
控制台信息
---------------获取所有的男性信息------------------
邓二-MALE-MARRIED
张三-MALE-SINGLE
王五-MALE-SINGLE
孙七-MALE-SINGLE
罗八-MALE-MARRIED
---------------获取所有单身------------------
张三-MALE-SINGLE
王五-MALE-SINGLE
赵六-FEMALE-SINGLE
孙七-MALE-SINGLE
刘九-FEMALE-SINGLE
史十-FEMALE-SINGLE
--------------------所有单身的男性-------------------
张三-MALE-SINGLE
王五-MALE-SINGLE
孙七-MALE-SINGLE
--------------------所有已婚的男性-------------------
邓二-MALE-MARRIED
罗八-MALE-MARRIED
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