[Part 001-GEF指南] -复制剪切粘贴拷贝

 

复制:

---

• Command:

public class CopyNodeCommand extends Command
{
        private ArrayList<Node> list = new ArrayList<Node>();
       
        public boolean addElement(Node node) {
                if (!list.contains(node)) {
                        return list.add(node);
                }
                return false;
        }
       
        @Override
        public boolean canExecute() {
                if (list == null || list.isEmpty())
                        return false;
                Iterator<Node> it = list.iterator();
                while (it.hasNext()) {
                        if (!isCopyableNode(it.next()))
                                return false;
                }
                return true;
        }
       
        @Override
        public void execute() {
                if (canExecute())
                        Clipboard.getDefault().s