cd.java

用command模式写的一个简单的java 程序

/******************************************************************************
*  Filename    :cd.java
*  Description :cd command
*
*  Author      :xunzy
*
*  History     :2004-02-16   Created
******************************************************************************/
import java.util.Vector;
import java.io.*;

class cd implements Command {

	public void execute(File currentDir, Vector v) throws CommandException {
	if (FileSystemShell.getCurrentDir() == null)
	throw new CommandException(new Exception(), "No current dir");
	else if (v.isEmpty())
	throw new CommandException(new Exception(), "No name specified");
	
	// get args[0] and throw away the other args
	else {
	String name = (String)v.firstElement();
	if(name.indexOf("/")>=0){
	    throw new CommandException(new Exception(), "Name error!!!\nCouldn't change to dir: " + name);
	}	
	if (name.equals("..")) {
	  String path=FileSystemShell.getParentDir();
	  FileSystemShell.setCurrentDir(path);          
	  int ind=path.lastIndexOf("\\"); 
	  if(path.substring(0,ind).endsWith(":")){
	    FileSystemShell.setParentDir(path.substring(0,ind+1));
	  }
	  else
	    FileSystemShell.setParentDir(path.substring(0,ind));
	  //System.out.println(FileSystemShell.getParentDir());
	  FileSystemShell.setCurrentFile(new File(FileSystemShell.getCurrentDir()));
	  System.out.println("Current Dir now :" + FileSystemShell.getCurrentDir());
	}
	else if (name.equals(".")) {
	  System.out.println("Current Dir now :" + FileSystemShell.getCurrentDir());
	}
	else if (name.equals("\\")) {
	  FileSystemShell.setCurrentDir(FileSystemShell.getDefaultDir());
	  FileSystemShell.setParentDir(FileSystemShell.getDefaultDir());
	  FileSystemShell.setCurrentFile(new File(FileSystemShell.getCurrentDir()));
	  System.out.println("Returning to default directory");
	}
	else {
	  char ch=':';
	  String dir;
	  if(FileSystemShell.getCurrentDir().endsWith("\\"))
	    dir=FileSystemShell.getCurrentDir()+name;
	  else
	    dir=FileSystemShell.getCurrentDir()+"\\"+name;
	  File c = new File(dir);
	  if(!c.exists()){
	    throw new CommandException(new Exception(), "Couldn't change to dir: " + name);
	  }
	  //String dirNew=dir.replaceAll("/","\\");
	  int ind=dir.lastIndexOf("\\"); 
	  FileSystemShell.setParentDir(dir.substring(0,ind));
	  //FileSystemShell.setParentDir(FileSystemShell.getCurrentDir());
	  FileSystemShell.setCurrentDir(dir);
	  FileSystemShell.setCurrentFile(c);
	  System.out.println("Current Dir now :" + FileSystemShell.getCurrentDir());
	}
    }
  }
    
  public void help() { System.out.println("Usage: cd [name]"); }
}