软件设计师（1）-2009年上半年下午JAVA

题目如下：



源码如下：

package 真题;

import java.util.ArrayList;
import java.util.List;

abstract class AbstractFile{
      //抽象类
    protected String name;
    public void printName(){
      System.out.println(name); }
    public abstract boolean addChild(AbstractFile file);
    public abstract boolean removeChile(AbstractFile file);
    public abstract List<AbstractFile> getChildren();
}

class File extends AbstractFile{
      //file哪有目录结构啊 所以都是false很正常
    public File(String name) {
      this.name = name; }
    @Override
    public boolean addChild(AbstractFile file) {
      return false; }
    @Override
    public boolean removeChile(AbstractFile file) {
      return false; }
    @Override
    public List<AbstractFile> getChildren() {
      return null; }
}

class Folder extends AbstractFile{
     
    private List<AbstractFile> childList;
    public Folder(String name) {
     
        this.name = name;
        this.childList = new ArrayList<AbstractFile>();
    }
    @Override
    public boolean addChild(AbstractFile file) {
     
        return childList.add(file);
    }
    @Override
    public boolean removeChile(AbstractFile file) {
     
        return childList.remove(file);
    }
    @Override
    public List<AbstractFile> getChildren() {
     
        return childList;
    }
}

public class test_2009 {
     
    public static void main(String[] args) {
     
        //构造一个树形的文件或者目录
        AbstractFile rootFolder = new Folder("c:\\");
        AbstractFile compositeFolder = new Folder("composite");
        AbstractFile windowsFolder = new Folder("windows");
        AbstractFile file = new File("TestComposite.java");

        rootFolder.addChild(compositeFolder);
        rootFolder.addChild(windowsFolder);
        compositeFolder.addChild(file);

        printTree(rootFolder);
    }
    private static void printTree(AbstractFile ifile){
     
        ifile.printName();
        List<AbstractFile> children = ifile.getChildren();
        if(children == null) return;
        for (AbstractFile file:children){
     
            printTree(file);
        }
    }
}

运行结果如下：