设计模式用例 (五)

1. 模板模式

interface Job {
    void execute();
}

abstract class Work implements Job {
    public void doWork() {
        Date begin = new Date();
        System.out.println("Begin working at" + begin);
        execute();
        Date end = new Date();
        System.out.println("End working at" + new Date()  + "\nTotal time is + " + (end.getTime() - begin.getTime()) + "ms");

    }
}

class HardWork extends Work {
    @Override
    public void execute() {
        try {
            Thread.sleep(1000);
        } catch (InterruptedException e) {
            // do nothing
        }
    }
}

public class TemplatePattern {
    public static void main(String[] args) {
        HardWork hw = new HardWork();
        hw.doWork();
    }
}
// output
//Begin working atFri Jan 04 17:29:05 GMT+08:00 2019
//End working atFri Jan 04 17:29:06 GMT+08:00 2019
// Total time is + 1045ms

2. Composite模式

interface Item {
    int getPrice();
    String getName();
}

class Bundle implements Item {
    private List<Item> items = new ArrayList<>();
    private String name;

    public Bundle(String name) {
        this.name = name;
    }

    public void add(Item item) {
        items.add(item);
    }

    public void remove(Item item) {
        items.remove(item);
    }

    public int getPrice() {
        int price = 0;
        for (Item item : items) {
            price += item.getPrice();
        }
        return price;
    }

    public String getName() {
        return name;
    }

    public String toString() {
        StringBuilder sb = new StringBuilder();
        sb.append(name);
        sb.append(": [");
        for (Item item : items) {
            sb.append(item.toString());
            sb.append(", ");
        }
        sb.append("]");
        return sb.toString();
    }
}

class LineItem implements Item {
    private int price = 0;
    private String name;

    public LineItem(int price, String name) {
        this.price = price;
        this.name = name;
    }

    public int getPrice() {
        return price;
    }

    public String getName() {
        return name;
    }

    public String toString() {
        return name;
    }
}

public class CompositePattern {
   // 购物车中有 两个单独买的物品，以及捆绑销售的1,2,3套餐。其中套餐2包含了套餐4
    public static void main(String[] args) {
        Bundle shoppingCart = new Bundle("Shopping Cart");
        shoppingCart.add(new LineItem(10,"item1"));
        shoppingCart.add(new LineItem(5,"item2"));

        Bundle bundle1 = new Bundle("Bundle1");
        bundle1.add(new LineItem(3, "I1B1"));
        bundle1.add(new LineItem(4, "I2B1"));

        Bundle bundle2 = new Bundle("Bundle2");
        bundle2.add(new LineItem(5, "I1B2"));

        Bundle bundle3 = new Bundle("EmptyBundle3");

        Bundle bundle4 = new Bundle("Bundle4");
        bundle4.add(new LineItem(7, "I1B4"));
        bundle2.add(bundle4);

        shoppingCart.add(bundle1);
        shoppingCart.add(bundle2);
        shoppingCart.add(bundle3);

        System.out.println("Total Price : " + shoppingCart.getPrice());
        System.out.println(shoppingCart);
    }
}

// output
//Total Price : 34
//Shopping Cart: [item1, item2, Bundle1: [I1B1, I2B1, ], Bundle2: [I1B2, Bundle4: [I1B4, ], ], EmptyBundle3: [], ]

3.原型模式

class Soldier implements Cloneable {
    private String job;
    private Weapon weapon;

    public Soldier(String job, Weapon weapon) throws InterruptedException {
        Thread.sleep(1);
        this.job = job;
        this.weapon = weapon;
    }

    public String toString() {
        return "Job: " + job + "; Weapon: " + weapon;
    }

    @Override
    protected Soldier clone() throws CloneNotSupportedException {
        Soldier soldier = (Soldier) super.clone();
        soldier.weapon = soldier.weapon.clone();
        return soldier;
    }

    public void setWeapon(Weapon weapon) {
        this.weapon = weapon;
    }
}

class Weapon implements Cloneable {
    private String weaponName;

    public Weapon(String weaponName) {
        this.weaponName = weaponName;
    }

    @Override
    protected Weapon clone() throws CloneNotSupportedException {
        return (Weapon) super.clone();
    }

    public String toString() {
        return weaponName;
    }
}
public class PrototypePattern {
    public static void main(String[] args) throws CloneNotSupportedException, InterruptedException {
        Soldier archer = new Soldier("Archer", new Weapon("Bow"));
        Soldier mage = new Soldier("Mage", new Weapon("Staff"));
        System.out.println("************Test Clone**************");
        Soldier clonedArcher = archer.clone();
        System.out.println(clonedArcher);
        Soldier clonedMage = mage.clone();
        System.out.println(clonedMage);
        System.out.println("************Test DEEP COPY*************");
        clonedMage.setWeapon(new Weapon("Dagger"));
        System.out.println(clonedMage);
        System.out.println(mage);

        System.out.println("************Test SPEED*************");
        Date cloneBegin = new Date();
        for (int i = 0; i < 1000; i++) {
            archer.clone();
            mage.clone();
        }
        System.out.println("Clone 1000 soldier takes " + (new Date().getTime() - cloneBegin.getTime()) + "ms");

        Date newBegin = new Date();
        for (int i = 0; i < 1000; i++) {
            new Soldier("Archer", new Weapon("Bow"));
            new Soldier("Mage", new Weapon("Staff"));
        }
        System.out.println("New 1000 soldier takes " + (new Date().getTime() - newBegin.getTime()) + "ms");
    }
}
// output
//************Test Clone**************
//Job: Archer; Weapon: Bow
//Job: Mage; Weapon: Staff
//************Test DEEP COPY*************
//Job: Mage; Weapon: Dagger
//Job: Mage; Weapon: Staff
//************Test SPEED*************
//Clone 1000 soldier takes 1ms
//New 1000 soldier takes 2093ms