過濾器模式（Filter Pattern）或标準模式（Criteria Pattern）是一種設計模式，這種模式允許開發人員使用不同的标準來過濾一組對象，通過邏輯運算以解耦的方式把它們連接配接起來。這種類型的設計模式屬于結構型模式，它結合多個标準來獲得單一标準。
實作
我們将建立一個 Person 對象、Criteria 接口和實作了該接口的實體類，來過濾 Person 對象的清單。CriteriaPatternDemo 類使用 Criteria 對象，基于各種标準和它們的結合來過濾 Person 對象的清單。
步驟 1
建立一個類，在該類上應用标準。
Person.java
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;
}
}
步驟 2
為标準（Criteria）建立一個接口。
Criteria.java
import java.util.List;
public interface Criteria {
public List<Person> meetCriteria(List<Person> persons);
步驟 3
建立實作了 Criteria 接口的實體類。
CriteriaMale.java
import java.util.ArrayList;
public class CriteriaMale implements Criteria {
@Override
public List<Person> meetCriteria(List<Person> persons) {
List<Person> malePersons = new ArrayList<Person>();
for (Person person : persons) {
if(person.getGender().equalsIgnoreCase("MALE")){
malePersons.add(person);
}
}
return malePersons;
CriteriaFemale.java
public class CriteriaFemale implements Criteria {
List<Person> femalePersons = new ArrayList<Person>();
if(person.getGender().equalsIgnoreCase("FEMALE")){
femalePersons.add(person);
return femalePersons;
CriteriaSingle.java
public class CriteriaSingle implements Criteria {
List<Person> singlePersons = new ArrayList<Person>();
if(person.getMaritalStatus().equalsIgnoreCase("SINGLE")){
singlePersons.add(person);
return singlePersons;
AndCriteria.java
public class AndCriteria implements Criteria {
private Criteria criteria;
private Criteria otherCriteria;
public AndCriteria(Criteria criteria, Criteria otherCriteria) {
this.criteria = criteria;
this.otherCriteria = otherCriteria;
List<Person> firstCriteriaPersons = criteria.meetCriteria(persons);
return otherCriteria.meetCriteria(firstCriteriaPersons);
OrCriteria.java
public class OrCriteria implements Criteria {
public OrCriteria(Criteria criteria, Criteria otherCriteria) {
List<Person> firstCriteriaItems = criteria.meetCriteria(persons);
List<Person> otherCriteriaItems = otherCriteria.meetCriteria(persons);
for (Person person : otherCriteriaItems) {
if(!firstCriteriaItems.contains(person)){
firstCriteriaItems.add(person);
}
return firstCriteriaItems;
步驟4
使用不同的标準（Criteria）和它們的結合來過濾 Person 對象的清單。
CriteriaPatternDemo.java
import java.util.ArrayList;
public class CriteriaPatternDemo {
public static void main(String[] args) {
List<Person> persons = new ArrayList<Person>();
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(List<Person> persons){
System.out.println("Person : [ Name : " + person.getName()
+", Gender : " + person.getGender()
+", Marital Status : " + person.getMaritalStatus()
+" ]");
}
步驟 5
執行程式，輸出結果：
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 ]