过滤器模式

1.过滤器模式简介
过滤器模式（Filter Pattern）又称标准模式（Criteria Pattern），用于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。属于结构型模式，它结合多个标准来获得单一标准。

2.测试Demo

import java.util.List;
import java.util.ArrayList;

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 this.name;
    }
    public String getGender() {
        return this.gender;
    }
    public String getMaritalStatus() {
        return this.maritalStatus;
    }
}


interface Criteria {
    public List<Person> meetCriteria(List<Person> persons);
}

class MaleCtiteria implements Criteria {
    @Override
    public List<Person> meetCriteria(List<Person> persons) {
        List<Person> maleMeet = new ArrayList<Person>();
        for (Person person : persons) {
            if (person.getGender().equalsIgnoreCase("MALE")) {
                maleMeet.add(person);
            }
        }
        return maleMeet;
    }
}

class FemaleCtiteria implements Criteria {
    @Override
    public List<Person> meetCriteria(List<Person> persons) {
        List<Person> femaleMeet = new ArrayList<Person>();
        for (Person person : persons) {
            if (person.getGender().equalsIgnoreCase("FEMALE")) {
                femaleMeet.add(person);
            }
        }
        return femaleMeet;
    }
}


class SingleCtiteria implements Criteria {
    @Override
    public List<Person> meetCriteria(List<Person> persons) {
        List<Person> singleMeet = new ArrayList<Person>();
        for (Person person : persons) {
            if (person.getMaritalStatus().equalsIgnoreCase("Single")) {
                singleMeet.add(person);
            }
        }
        return singleMeet;
    }
}


class AndCtiteria implements Criteria {
    private Criteria meetCriteria1;
    private Criteria meetCriteria2;

    public AndCtiteria(Criteria meetCriteria1, Criteria meetCriteria2) {
        this.meetCriteria1 = meetCriteria1;
        this.meetCriteria2 = meetCriteria2;
    }

    @Override
    public List<Person> meetCriteria(List<Person> persons) {
        List<Person> andMeet = meetCriteria1.meetCriteria(persons);
        andMeet = meetCriteria2.meetCriteria(andMeet);

        return andMeet;
    }
}


class OrCtiteria implements Criteria {
    private Criteria selectCriteria1;
    private Criteria selectCriteria2;

    public OrCtiteria(Criteria selectCriteria1, Criteria selectCriteria2) {
        this.selectCriteria1 = selectCriteria1;
        this.selectCriteria2 = selectCriteria2;
    }

    @Override
    public List<Person> meetCriteria(List<Person> persons) {
        List<Person> selectMeet1 = selectCriteria1.meetCriteria(persons);
        List<Person> selectMeet2 = selectCriteria2.meetCriteria(persons);

        for (Person person : selectMeet1) {
            if (!selectMeet2.contains(person)) {
                selectMeet2.add(person);
            }
        }

        return selectMeet2;
    }
}



public class MeteriaPatternDemo {
    public static void main(String args[]) {
        List<Person> persons = new ArrayList<Person>();
        persons.add(new Person("Jane", "MALE", "Single"));
        persons.add(new Person("July", "FEMALE", "Married"));
        persons.add(new Person("Kitty", "MALE", "Married"));
        persons.add(new Person("James", "FEMALE", "Single"));

        Criteria maleCriteria = new MaleCtiteria();
        Criteria singleCriteria = new SingleCtiteria();
        Criteria andCriteria = new AndCtiteria(maleCriteria, singleCriteria);
        Criteria orCriteria = new OrCtiteria(maleCriteria, singleCriteria);

        System.out.println("Male:");
        PrintPerson(maleCriteria.meetCriteria(persons));

        System.out.println("Single:");
        PrintPerson(singleCriteria.meetCriteria(persons));

        System.out.println("Male and Single:");
        PrintPerson(andCriteria.meetCriteria(persons));

        System.out.println("Male or Single:");
        PrintPerson(orCriteria.meetCriteria(persons));
    }


    public static void PrintPerson(List<Person> persons) {
        for (Person person : persons) {
            System.out.println("name=" + person.getName() + "  " + "gender=" + person.getGender() + "  " + "maritalStatus=" + person.getMaritalStatus());        
        }
    }
}

参考：http://www.runoob.com/design-pattern/filter-pattern.html