public class MyLayout {

private String type;
private int rows;
private int cols;
private int hgap;
private int vgap;

/**
* constructor
* @param al
* @throws Exception
*/
public MyLayout(ArrayList<String> al) throws Exception {
   // get a token
   // try to identify it
   String str = al.remove(0);
   if (str.equals("Layout") == false) {
         throw new Exception("Expecting Layout found: " + str);
   }
   hgap = -1;

   // get out strings until we could get a colon
   str = "";
   String tmp;
   do {
         tmp = al.remove(0);
         str += tmp + " ";
   } while (tmp.contains(":") == false);

   setLayout(str.trim());

}

/**
* parse and set up the layout
* @param str
* @throws Exception
*/
private void setLayout(String str) throws Exception {
   // we expect a colon at the end of this string
   if (str.endsWith(":") == false) {
         throw new Exception("Expecting ':' at the end of: " + str);
   }
   // remove the colon
   str = str.substring(0, str.length() - 1);

   if (str.equals("Flow") == true) {
         type = str;
   } else if (str.startsWith("Grid")) {
         type = "Grid";
         // remove Grid
         setGrid(str.substring(4).trim()); // lengrh of "Grid" is 4
   } else {
         throw new Exception("Expecting 'Flow' or 'Grid at the start of: " + str);
   }

}

private void setGrid(String str) throws Exception {
   if (str.startsWith("(") == false) {
         throw new Exception("Expecting ( at start of: " + str);
   }
   if (str.endsWith(")") == false) {
         throw new Exception("Expecting ) at end of: " + str);
   }
   str = str.substring(1, str.length() - 1);
   // str == NUMBER ',' NUMBER [',' NUMBER ',' NUMBER]
   String[] sp = str.split(",");
   if (sp.length == 2) {
         rows = Integer.parseInt(sp[0].trim());
         cols = Integer.parseInt(sp[1].trim());

   } else if (sp.length == 4) {
         rows = Integer.parseInt(sp[0].trim());
         cols = Integer.parseInt(sp[1].trim());
         hgap = Integer.parseInt(sp[2].trim());
         vgap = Integer.parseInt(sp[3].trim());

   } else {
         throw new Exception("Expecting 2 or 4 numbers "
               + "seperated by commas found: " + str);
   }
}

@Override
public String toString() {
   String s = "";
   if (type.equals("Flow")) {
         s = "new FlowLayout()";
   } else {
         s = "new GridLayout( " + rows + ", " + cols;
         if (hgap > 0) {
            s += ", " + hgap + ", " + vgap;
         }
         s += ")";
   }
   return s;
}

}

Problem Description: A city is laid out as a rectangular grid as y...