부동점수 형식의number를 영어로 변환하는 표현 방식

public class ConvertNumToStr {
	public static String parse(Object x) {
		if (x != null) {
			return parse(x + "");
		} else {
			return "";
		}
	}
	
	private static String parse(String x) {
		int z = x.indexOf("."); //       
		String lstr = "", rstr = "";
		if (z > -1) { //       ，   ，         
			lstr = x.substring(0, z);
			rstr = x.substring(z + 1);
		} else
			//       
			lstr = x;
		
		String lstrrev = reverse(lstr); //         
		String[] a = new String [5]; //   5                    
		
		switch (lstrrev.length() % 3) {
		case 1:
			lstrrev += "00";
			break;
		case 2:
			lstrrev += "0";
			break;
		}
		String lm = ""; //             
		for (int i = 0; i < lstrrev.length() / 3; i++) {
			a[i] = reverse(lstrrev.substring(3 * i, 3 * i + 3)); //        
			if (!a[i].equals("000")) { //         ：1000000 = one million
				                       // thousand only
				if (i != 0)
					lm = transThree(a[i]) + " " + parseMore(String.valueOf(i)) + " " + lm; //  :
					                                                                       // thousand、million、billion
				else
					lm = transThree(a[i]); //   i=0 ，        .
			} else
				lm += transThree(a[i]);
		}
		
		String xs = ""; //            
		if (z > -1)
			xs = "AND CENTS " + transTwo(rstr) + " "; //            
			
		return lm.trim() + " " + xs + "ONLY";
	}
	
	private static String parseFirst(String s) {
		String[] a = new String [] { "", "ONE", "TWO", "THREE", "FOUR", "FIVE", "SIX", "SEVEN", "EIGHT", "NINE"};
		return a[Integer.parseInt(s.substring(s.length() - 1))];
	}
	
	private static String parseTeen(String s) {
		String[] a = new String [] { "TEN", "ELEVEN", "TWELEVE", "THIRTEEN", "FOURTEEN", "FIFTEEN", "SIXTEEN", "SEVENTEEN", "EIGHTEEN", "NINETEEN"};
		return a[Integer.parseInt(s) - 10];
	}
	
	private static String parseTen(String s) {
		String[] a = new String [] { "TEN", "TWENTY", "THIRTY", "FORTY", "FIFTY", "SIXTY", "SEVENTY", "EIGHTY", "NINETY"};
		return a[Integer.parseInt(s.substring(0, 1)) - 1];
	}
	
	//   
	private static String transTwo(String s) {
		String value = "";
		//     
		if (s.length() > 2)
			s = s.substring(0, 2);
		else if (s.length() < 2)
			s = "0" + s;
		
		if (s.startsWith("0")) // 07 - seven     10
			value = parseFirst(s);
		else if (s.startsWith("1")) // 17 seventeen    10 20  
			value = parseTeen(s);
		else if (s.endsWith("0")) //    10 100     10    
			value = parseTen(s);
		else
			value = parseTen(s) + " " + parseFirst(s);
		return value;
	}
	
	private static String parseMore(String s) {
		String[] a = new String [] { "", "THOUSAND", "MILLION", "BILLION"};
		return a[Integer.parseInt(s)];
	}
	
	//       
	// s.length = 3
	private static String transThree(String s) {
		String value = "";
		if (s.startsWith("0")) //     100
			value = transTwo(s.substring(1));
		else if (s.substring(1).equals("00")) //    100  
			value = parseFirst(s.substring(0, 1)) + " HUNDRED";
		else
			value = parseFirst(s.substring(0, 1)) + " HUNDRED AND " + transTwo(s.substring(1));
		return value;
	}
	
	private static String reverse(String s) {
		char[] aChr = s.toCharArray();
		StringBuffer tmp = new StringBuffer();
		for (int i = aChr.length - 1; i >= 0; i--) {
			tmp.append(aChr[i]);
		}
		return tmp.toString();
	}
	
	public static void main(String[] args) {
		System.out.println("*** " + ConvertNumToStr.parse("100.23"));
		System.out.println("*** " + ConvertNumToStr.parse("2100.00"));
	}
}