设计模式学习8 Composite

应用场景：

实现代码:

public interface IBox
{
void Process();
void Add(IBox box);
void Remove(IBox box);
}

public class SingleBox : IBox
{
public void Process()
{
// do process for myself
}

public void Add(IBox box)
{
// 两个实现方案
// 1. do nothing
// 2. throw exception
}

public void Remove(IBox box)
{
// 1. do nothing or
// 2. throw exception
}
}

public class ContainerBox : IBox
{
// do process for myself

// do the process fo r the box in the list

ArrayList list;
public void Process()
{
if (list != null)
{
foreach (IBox box in list)
{
box.Process();
}
}
}

public void Add(IBox box)
{
if (list == null)
{
list = new ArrayList();
}

list.Add(box);
}

public void Remove (IBox box)
{
if (list == null)
{
throw new Exception();
}

list.Remove(box);
}

public ArrayList GetBoxes()
{
return list;
}
}