8) Filter/Criteria Pattern

类别：

 Structual Pattern

问题：

 

方案：

 

 

 

示例：

 

import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

public class CriteriaPatternDemo {
    public static void main(String[] args) {

        List<Person> persons = new ArrayList<Person>();
        persons.add(new Person("小强", "男", "未婚"));
        persons.add(new Person("小明", "男", "未婚"));
        persons.add(new Person("小李", "男", "已婚"));
        persons.add(new Person("小红", "女", "已婚"));
        persons.add(new Person("小月", "女", "已婚"));
        persons.add(new Person("小兰", "女", "未婚"));

        Criteria male = new Male();
        Criteria female = new Female();
        Criteria single = new Single();
        Criteria singleMale = new And(single, male);
        Criteria singleOrFemale = new Or(single, female);

        System.out.println("男: ");
        printPersons(male.filter(persons));
        System.out.println("\n女: ");
        printPersons(female.filter(persons));
        System.out.println("\n未婚男: ");
        printPersons(singleMale.filter(persons));
        System.out.println("\n未婚或者女: ");
        printPersons(singleOrFemale.filter(persons));
    }

    public static void printPersons(List<Person> persons) {
        for (Person person : persons) {
            System.out.println(person);
        }
    }
}

class Person {
    private String name;
    private String sex;
    private String marriage;

    public Person(String name, String sex, String marriage) {
        this.name = name;
        this.sex = sex;
        this.marriage = marriage;
    }

    public String getName() {
        return name;
    }

    public String getSex() {
        return sex;
    }

    public String getMarriage() {
        return marriage;
    }

    @Override
    public String toString() {
        return "Person [name=" + name + ", sex=" + sex + ", marriage=" + marriage + "]";
    }

}

interface Criteria {
    public List<Person> filter(List<Person> list);
}

class Male implements Criteria {
    @Override
    public List<Person> filter(List<Person> list) {
        List<Person> malePersonList = new ArrayList<Person>();
        for (Person person : list) {
            if (person.getSex().equalsIgnoreCase("男")) {
                malePersonList.add(person);
            }
        }
        return malePersonList;
    }
}

class Female implements Criteria {
    @Override
    public List<Person> filter(List<Person> list) {
        List<Person> femalePersonList = new ArrayList<Person>();
        for (Person person : list) {
            if (person.getSex().equalsIgnoreCase("女")) {
                femalePersonList.add(person);
            }
        }
        return femalePersonList;
    }
}

class Single implements Criteria {
    @Override
    public List<Person> filter(List<Person> list) {
        List<Person> singlePersonList = new ArrayList<Person>();
        for (Person person : list) {
            if (person.getMarriage().equalsIgnoreCase("未婚")) {
                singlePersonList.add(person);
            }
        }
        return singlePersonList;
    }
}

class And implements Criteria {
    private Criteria a;
    private Criteria b;

    public And(Criteria a, Criteria b) {
        this.a = a;
        this.b = b;
    }

    @Override
    public List<Person> filter(List<Person> list) {
        List<Person> aList = a.filter(list);
        return b.filter(aList);
    }
}

class Or implements Criteria {
    private Criteria a;
    private Criteria b;

    public Or(Criteria a, Criteria b) {
        this.a = a;
        this.b = b;
    }

    @Override
    public List<Person> filter(List<Person> list) {
        List<Person> aList = a.filter(list);
        List<Person> bList = b.filter(list);
        Set<Person> set = new HashSet<Person>();
        set.addAll(aList);
        set.addAll(bList);
        return new ArrayList<Person>(set);
    }
}

 

男: 
Person [name=小强, sex=男, marriage=未婚]
Person [name=小明, sex=男, marriage=未婚]
Person [name=小李, sex=男, marriage=已婚]

女: 
Person [name=小红, sex=女, marriage=已婚]
Person [name=小月, sex=女, marriage=已婚]
Person [name=小兰, sex=女, marriage=未婚]

未婚男: 
Person [name=小强, sex=男, marriage=未婚]
Person [name=小明, sex=男, marriage=未婚]

未婚或者女: 
Person [name=小兰, sex=女, marriage=未婚]
Person [name=小月, sex=女, marriage=已婚]
Person [name=小强, sex=男, marriage=未婚]
Person [name=小明, sex=男, marriage=未婚]
Person [name=小红, sex=女, marriage=已婚]

 

应用：

 

不足：(

 

优化：）