java 设计模式学习笔记八 composite组合模式

composite组合模式

将对象以树形式组织起来和chain of responsibility模式类似

好处：

可以一致使用组合结构和单个对象

不必关心组合体内是否加入新部件

示例代码：

/**

* 组合体接口

*

* @time 下午09:05:03

* @author retacn yue

* @Email zhenhuayue@sina.com

*/

public abstract class Equipment {

@SuppressWarnings("unused")

private String name;

// 实际价格

public abstract double netPrice();

// 折扣价格

public abstract double discountPrice();

// 添加部件

public boolean add(Equipment equipment) {

return false;

}

// 删除部件

public boolean remove(Equipment equipment) {

return false;

}

// 访问组合体的方法

@SuppressWarnings("rawtypes")

public Iterator iter() {

return null;

}

public Equipment(String name) {

this.name = name;

}

}

/**

* 部件桌子

*

* @time 下午09:12:01

* @author retacn yue

* @Email zhenhuayue@sina.com

*/

public class Disk extends Equipment {

/**

* 构造器

*

* @param name

*/

public Disk(String name) {

super(name);

}

@Override

public double netPrice() {

return 1;

}

@Override

public double discountPrice() {

return 0.5;

}

}

/**

* 组合体部件

*

* @time 下午09:13:41

* @author retacn yue

* @Email zhenhuayue@sina.com

*/

@SuppressWarnings("rawtypes")

public class CompositeEquipment extends Equipment {

private int i = 0;

// 用来存放子控件

private List equipment = new ArrayList();

/**

* 构造器

*

* @param name

*/

public CompositeEquipment(String name) {

super(name);

}

@SuppressWarnings("unchecked")

@Override

public boolean add(Equipment equipment) {

this.equipment.add(equipment);

return true;

}

@Override

public double netPrice() {

double netPrice = 0;

Iterator iterator = equipment.iterator();

while (iterator.hasNext()) {

netPrice += ((Equipment) iterator.next()).netPrice

();

}

return netPrice;

}

@Override

public double discountPrice() {

double discountPrice = 0;

Iterator iterator = equipment.iterator();

while (iterator.hasNext()) {

discountPrice += ((Equipment) iterator.next

()).discountPrice();

}

return discountPrice;

}

// 访问本组合体内部件的方法

public Iterator iter() {

return equipment.iterator();

}

public boolean hasNext() {

return i < equipment.size();

}

public Object next() {

if (hasNext()) {

return equipment.get(i++);

} else {

throw new NoSuchElementException();

}

}

}

/**

* 框箱

*

* @time 下午09:31:14

* @author retacn yue

* @Email zhenhuayue@sina.com

*/

public class Cabinet extends CompositeEquipment {

public Cabinet(String name) {

super(name);

}

@Override

public double netPrice() {

return 1 + super.netPrice();

}

@Override

public double discountPrice() {

return .5 + super.discountPrice();

}

}

/**

* 盘盒

*

* @time 下午09:30:18

* @author retacn yue

* @Email zhenhuayue@sina.com

*/

public class Chassis extends CompositeEquipment {

public Chassis(String name) {

super(name);

}

@Override

public double netPrice() {

return 1 + super.netPrice();

}

@Override

public double discountPrice() {

return .5 + super.discountPrice();

}

}

/**

* 测试组合模式

*

* @time 下午09:33:44

* @author retacn yue

* @Email zhenhuayue@sina.com

*/

public class TestComposite {

public static void main(String[] args) {

Cabinet cabinet = new Cabinet("Tower");

Chassis chassis = new Chassis("PC Chassis");

// 将chassis装到tower中

cabinet.add(chassis);

cabinet.netPrice();

cabinet.discountPrice();

}

}