This was so trivial, I wonder why Sun didn’t do it in the first place…
It launches a new process and listens for the stdout:
- Windows:
cmd /c dir /B $path - Linux/Unix:
/bin/ls $path
public interface DirectoryVisitor
{
public void visit(File parent, String name);
}
public class DirectoryIterator
{
public static void main(String[] args) throws Exception
{
DirectoryVisitor visitor = new DirectoryVisitor()
{
@Override
public void visit(File parent, String name)
{
System.out.println("file: " + name);
}
};
iterate(new File(args[0]), visitor);
}
public static void iterate(File directory, DirectoryVisitor visitor)
{
String path = directory.getAbsolutePath();
if (!directory.isDirectory())
{
throw new IllegalStateException("file not a directory: " + path);
}
if (System.getProperty("os.name").toLowerCase().contains("windows"))
{
try
{
String[] cmd = new String[5];
cmd[0] = "cmd";
cmd[1] = "/c";
cmd[2] = "dir";
cmd[3] = "/B"; // by: irreversible_kev
cmd[4] = path;
Process p = Runtime.getRuntime().exec(cmd);
BufferedReader br = new BufferedReader(new InputStreamReader(p.getInputStream()));
while (true)
{
String line = br.readLine();
if (line == null)
break;
visitor.visit(directory, line);
}
int ev = p.waitFor();
if (ev != 0)
{
throw new IllegalStateException("cmd exit value: " + ev);
}
}
catch (Exception exc)
{
throw new IllegalStateException(exc);
}
}
else
{
try
{
String[] cmd = new String[2];
cmd[0] = "/bin/ls";
cmd[1] = path;
Process p = Runtime.getRuntime().exec(cmd);
BufferedReader br = new BufferedReader(new InputStreamReader(p.getInputStream()));
while (true)
{
String line = br.readLine();
if (line == null)
break;
visitor.visit(directory, line);
}
int ev = p.waitFor();
if (ev != 0)
{
throw new IllegalStateException("/bin/ls exit value: " + ev);
}
}
catch (Exception exc)
{
throw new IllegalStateException(exc);
}
}
}
}
