1、简介
过滤器模式(Filter Pattern),这种模式允许开发人员以不同的标准来过滤一组对象,通过逻辑运算以解耦的方式将他们连接起来。
2、测试
// 过滤接口
public interface Criteria {
List<People> meetingPeople(List<People> peoples);
}
// 具体过滤类
public class CriteriaFemale implements Criteria{
@Override
public List<People> meetingPeople(List<People> peoples) {
List<People> femalePeoples = new ArrayList<People>();
for(People peo: peoples) {
if(peo.getGender().equalsIgnoreCase("female")) {
femalePeoples.add(peo);
}
}
return femalePeoples;
}
}
public class CriteriaMale implements Criteria{
@Override
public List<People> meetingPeople(List<People> peoples) {
List<People> malePeoples = new ArrayList<People>();
for(People peo: peoples) {
if(peo.getGender().equalsIgnoreCase("male")) {
malePeoples.add(peo);
}
}
return malePeoples;
}
}
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<People> meetingPeople(List<People> peoples) {
return otherCriteria.meetingPeople(criteria.meetingPeople(peoples));
}
}
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<People> meetingPeople(List<People> peoples) {
List<People> firstCriteriaPeoples = criteria.meetingPeople(peoples);
List<People> otherCriteriaPeoples = otherCriteria.meetingPeople(peoples);
for(People peo: firstCriteriaPeoples) {
if(!otherCriteriaPeoples.contains(peo)) {
otherCriteriaPeoples.add(peo);
}
}
return otherCriteriaPeoples;
}
}
public class CriteriaSingle implements Criteria{
@Override
public List<People> meetingPeople(List<People> peoples) {
List<People> singlePeoples = new ArrayList<People>();
for(People peo: peoples) {
if(peo.getMaritalStatus().equalsIgnoreCase("single")) {
singlePeoples.add(peo);
}
}
return singlePeoples;
}
}
List<People> peoples = new ArrayList<People>(10);
People peo1 = new People("Robert One", "male", "single");
People peo2 = new People("Robert Two", "female", "double");
People peo3 = new People("Robert Three", "male", "single");
People peo4 = new People("Robert Four", "male", "single");
People peo5 = new People("Robert Five", "female", "double");
People peo6 = new People("Robert Six", "male", "single");
People peo7 = new People("Robert Seven", "female", "single");
People peo8 = new People("Robert Eight", "male", "double");
People peo9 = new People("Robert Nine", "male", "single");
People peo10 = new People("Robert Ten", "male", "single");
peoples.add(peo1);
peoples.add(peo2);
peoples.add(peo3);
peoples.add(peo4);
peoples.add(peo5);
peoples.add(peo6);
peoples.add(peo7);
peoples.add(peo8);
peoples.add(peo9);
peoples.add(peo10);
Criteria maleCriteria = new CriteriaMale();
Criteria femaleCriteria = new CriteriaFemale();
Criteria singleCriteria = new CriteriaSingle();
Criteria andCriteria = new AndCriteria(singleCriteria, maleCriteria);
Criteria orCriteria = new OrCriteria(singleCriteria, femaleCriteria);
System.out.println("male--------------------------------------------------");
Utils.printList(maleCriteria.meetingPeople(peoples));
System.out.println("female--------------------------------------------------");
Utils.printList(femaleCriteria.meetingPeople(peoples));
System.out.println("and single male--------------------------------------------------");
Utils.printList(andCriteria.meetingPeople(peoples));
System.out.println("or single female--------------------------------------------------");
Utils.printList(orCriteria.meetingPeople(peoples));