德州购物网站建设,简单的企业网站,策划公司主要做什么,hao123网址导航Java过滤器模式 实现范例 过滤器模式#xff08;Filter Pattern#xff09;或允许开发人员使用不同的标准来过滤一组对象#xff0c;通过逻辑运算以解耦的方式把它们连接起来 过滤器模式#xff08;Filter Pattern#xff09; 又称 标准模式#xff08;Criteria Pattern… Java过滤器模式 实现范例 过滤器模式Filter Pattern或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 过滤器模式Filter Pattern 又称 标准模式Criteria Pattern
过滤器模式属于结构型模式它结合多个标准来获得单一标准
实现 创建一个Person对象、Criteria接口和实现了该接口的实体类来过滤Person对象的列表CriteriaPatternDemo使用Criteria对象基于各种标准和它们的结合来过滤Person对象的列表
范例
1. 创建一个类在该类上应用标准.
Person.java
package com.demo.gof;
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;}
}
2. 为标准Criteria创建一个接口
Criteria.java
package com.demo.gof;
import java.util.List;public interface Criteria {public ListPerson meetCriteria(ListPerson persons);
}3. 创建实现了 Criteria 接口的实体类
CriteriaMale.java
package com.demo.gof;
import java.util.ArrayList;
import java.util.List;public class CriteriaMale implements Criteria {Overridepublic ListPerson meetCriteria(ListPerson persons) {ListPerson malePersons new ArrayListPerson(); for (Person person : persons) {if(person.getGender().equalsIgnoreCase(MALE)){malePersons.add(person);}}return malePersons;}
}CriteriaFemale.java
package com.demo.gof;
import java.util.ArrayList;
import java.util.List;public class CriteriaFemale implements Criteria {Overridepublic ListPerson meetCriteria(ListPerson persons) {ListPerson femalePersons new ArrayListPerson(); for (Person person : persons) {if(person.getGender().equalsIgnoreCase(FEMALE)){femalePersons.add(person);}}return femalePersons;}
}CriteriaSingle.java
package com.demo.gof;
import java.util.ArrayList;
import java.util.List;public class CriteriaSingle implements Criteria {Overridepublic ListPerson meetCriteria(ListPerson persons) {ListPerson singlePersons new ArrayListPerson(); for (Person person : persons) {if(person.getMaritalStatus().equalsIgnoreCase(SINGLE)){singlePersons.add(person);}}return singlePersons;}
}AndCriteria.java
package com.demo.gof;
import java.util.List;public class AndCriteria implements Criteria {private Criteria criteria;private Criteria otherCriteria;public AndCriteria(Criteria criteria, Criteria otherCriteria) {this.criteria criteria;this.otherCriteria otherCriteria; }Overridepublic ListPerson meetCriteria(ListPerson persons) {ListPerson firstCriteriaPersons criteria.meetCriteria(persons); return otherCriteria.meetCriteria(firstCriteriaPersons);}OrCriteria.java
package com.demo.gof;
import java.util.List;public class OrCriteria implements Criteria {private Criteria criteria;private Criteria otherCriteria;public OrCriteria(Criteria criteria, Criteria otherCriteria) {this.criteria criteria;this.otherCriteria otherCriteria; }Overridepublic ListPerson meetCriteria(ListPerson persons) {ListPerson firstCriteriaItems criteria.meetCriteria(persons);ListPerson otherCriteriaItems otherCriteria.meetCriteria(persons);for (Person person : otherCriteriaItems) {if(!firstCriteriaItems.contains(person)){firstCriteriaItems.add(person);}} return firstCriteriaItems;}
}4. 使用不同的标准Criteria和它们的结合来过滤 Person 对象的列表
CriteriaPatternDemo.java
package com.demo.gof;
import java.util.ArrayList;
import java.util.List;public class CriteriaPatternDemo {public static void main(String[] args) {ListPerson persons new ArrayListPerson();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,Male, Single));Criteria male new CriteriaMale();Criteria female new CriteriaFemale();Criteria single new CriteriaSingle();Criteria singleMale new AndCriteria(single, male);Criteria singleOrFemale new OrCriteria(single, female);System.out.println(Males: );printPersons(male.meetCriteria(persons));System.out.println(\nFemales: );printPersons(female.meetCriteria(persons));System.out.println(\nSingle Males: );printPersons(singleMale.meetCriteria(persons));System.out.println(\nSingle Or Females: );printPersons(singleOrFemale.meetCriteria(persons));}public static void printPersons(ListPerson persons){for (Person person : persons) {System.out.println(Person : [ Name : person.getName() , Gender : person.getGender() , Marital Status : person.getMaritalStatus() ]);}}
}编译运行以上 Java 范例输出结果如下
$ javac -d . src/main/com.demo/gof/CriteriaPatternDemo.java
$ java com.demo.gof.CriteriaPatternDemo
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 ]
Person : [ Name : Bobby, Gender : Male, Marital Status : Single ]Females:
Person : [ Name : Laura, Gender : Female, Marital Status : Married ]
Person : [ Name : Diana, Gender : Female, Marital Status : Single ]Single Males:
Person : [ Name : Robert, Gender : Male, Marital Status : Single ]
Person : [ Name : Mike, Gender : Male, Marital Status : Single ]
Person : [ Name : Bobby, Gender : Male, Marital Status : Single ]Single Or Females:
Person : [ Name : Robert, Gender : Male, Marital Status : Single ]
Person : [ Name : Diana, Gender : Female, Marital Status : Single ]
Person : [ Name : Mike, Gender : Male, Marital Status : Single ]
Person : [ Name : Bobby, Gender : Male, Marital Status : Single ]
Person : [ Name : Laura, Gender : Female, Marital Status : Married ]
