Action Point Of Sale Code

package cell;
abstract class CellLinkDown extends CellFile
{
 abstract CellBase boot(String fileName);
 String fileName;
 CellLinkDown(String fileName)
 {
  super(fileName);
  this.fileName = fileName.toUpperCase();
  }
 void transmit(short row, String dest, float diff, byte shifted, float frac)
 {
  CellBase d = boot(dest);
  float old = d.af(shifted, row);
  float answer = old + (diff * frac);
  d.so( shifted, row, new Float(answer));
  }
 static String match(String reg, String fix, String src)
 // returns the dest file name, or null
 {
  String mat = "";
  for (int i = 0; i < reg.length(); i++)
  if (reg.charAt(i) == '*') mat += fix.charAt(i);
  else if (reg.charAt(i) == '+') mat += src.charAt(i);
  else mat += reg.charAt(i);
  reg = mat;
  mat = "";
  for (int i = 0; i < fix.length(); i++)
  if (fix.charAt(i) == '+') mat += reg.charAt(i);
  else mat += fix.charAt(i);
  fix = mat;
  if (!reg.equalsIgnoreCase(fix)) return null;
  return reg;
  }
 }