RussianMoney.java

package net.sf.lab3f.util;

import java.util.Stack;

public class RussianMoney {

	private static enum Ranges {UNITS, DECADES, HUNDREDS, THOUSANDS, MILLIONS, BILLIONS};

	private static Stack <ThreeChar> threeChars;

    private static class ThreeChar {
		char h, d, u;
		Ranges range;
	}	

	public static String digits2Text(Double d){
		if(d == null || d < 0.0) return null;
		String s = d.toString();
		int n = s.length() - s.lastIndexOf('.');
		if(n > 3) return null;
		if(n == 2) s += "0";
		String[] sa = s.split("\\.");
        threeChars = new Stack <ThreeChar> ();
		threeChars.push(new ThreeChar());
		threeChars.peek().range = Ranges.UNITS;
		StringBuilder sb = new StringBuilder(sa[0]).reverse();
        for(int i = 0; i < sb.length(); i++){
          if(i > 0 && i % 3 == 0){
 		   threeChars.push(new ThreeChar()); 
		  } 
		  ThreeChar	threeChar = threeChars.peek();
		  switch(i){
			   case 0: 
				   threeChar.u = sb.charAt(i);
				   break;
			   case 3: 
				   threeChar.range = Ranges.THOUSANDS; 
				   threeChar.u = sb.charAt(i);
				   break;
			   case 6: 
				   threeChar.range = Ranges.MILLIONS;  
				   threeChar.u = sb.charAt(i);
				   break;
			   case 9: 
				   threeChar.range = Ranges.BILLIONS;  
				   threeChar.u = sb.charAt(i);
				   break;
			   case 2: 
			   case 5: 
			   case 8: 
				   threeChar.h = sb.charAt(i);
				   break;
			   default:
				   threeChar.d = sb.charAt(i);
		  }	   
		}
		StringBuilder result = new StringBuilder();
	    while(!threeChars.isEmpty()){
			ThreeChar thch = threeChars.pop();
            if(thch.h > 0  ){
				result.append(getHundreds(thch.h));
			    result.append(' ');
			}
            if(thch.d > '0'){
				if(thch.d > '1' || (thch.d == '1' && thch.u == '0')) result.append(getDecades(thch.d));
				else if(thch.d > '0') result.append(getTeens(thch.d));
			    result.append(' ');
			}
            if(thch.u > '0' && thch.d != '1'){
				result.append(getUnits(thch.u, thch.range == Ranges.THOUSANDS));
			    result.append(' ');
   		    }
			switch(thch.range){
				case BILLIONS:
					if(thch.d == '1' || thch.u == '0') result.append("миллиардов");
					else if(thch.u > '4')result.append("миллиардов");
					else if(thch.u > '1')result.append("миллиарда");
					else result.append("миллиард");
					break;
				case MILLIONS:
					if(thch.d == '1' || thch.u == '0') result.append("миллионов");
					else if(thch.u > '4')result.append("миллионов");
					else if(thch.u > '1')result.append("миллиона");
					else result.append("миллион");
					break;
				case THOUSANDS:
					if(thch.d == '1' || thch.u == '0') result.append("тысяч");
					else if(thch.u > '4')result.append("тысяч");
					else if(thch.u > '1')result.append("тысячи");
					else result.append("тысяча");
					break;
				default:
					if(thch.d == '1' || thch.u == '0' || thch.u > '4')result.append("рублей");
					else if(thch.u > '1')result.append("рубля");
					else result.append("рубль");
			}
			result.append(' ');
		}	
		result.append(sa[1] + ' ');
		switch(sa[1].charAt(1)){
			case '1': 
				result.append(sa[1].charAt(0) != '1' ? "копейка" : "копеек");
				break;
			case '2': 
			case '3': 
			case '4': 
				result.append(sa[1].charAt(0) != '1' ? "копейки" : "копеек");
				break;
			default:
				result.append("копеек");
		}
        char first = Character.toUpperCase(result.charAt(0));
		result.setCharAt(0, first);
		return result.toString();
	}

    private static String getHundreds(char dig){
     switch(dig){
		 case '1': 
			 return "сто";
		 case '2': 
			 return "двести";
		 case '3': 
			 return "триста";
		 case '4': 
			 return "четыреста";
		 case '5': 
			 return "пятьсот";
		 case '6': 
			 return "шестсот";
		 case '7': 
			 return "семсот";
		 case '8': 
			 return "восемсот";
		 case '9': 
			 return "девятьсот";
		 default: return null;
	 }		
	}

    private static String getDecades(char dig){
     switch(dig){
		 case '1': 
			 return "десять";
		 case '2': 
			 return "двадцать";
		 case '3': 
			 return "тридцать";
		 case '4': 
			 return "сорок";
		 case '5': 
			 return "пятьдесят";
		 case '6': 
			 return "шестьдесят";
		 case '7': 
			 return "семьдесят";
		 case '8': 
			 return "восемьдесят";
		 case '9': 
			 return "девяносто";
		 default: return null;
	 }		
	}

    private static String getUnits(char dig, boolean female){
     switch(dig){
		 case '1': 
			 return female ? "одна" : "один";
		 case '2': 
			 return female ? "две"  : "два";
		 case '3': 
			 return "три";
		 case '4': 
			 return "четыре";
		 case '5': 
			 return "пять";
		 case '6': 
			 return "шесть";
		 case '7': 
			 return "семь";
		 case '8': 
			 return "восемь";
		 case '9': 
			 return "девять";
		 default: return null;
	 }		
	}

    private static String getTeens(char dig){
     String s = "";		
     switch(dig){
		 case '1':
			 s = "один"; break;
		 case '2':
			 s = "две"; break;
		 case '3':
			 s = "три"; break;
		 case '4':
			 s = "четыр"; break;
		 case '5':
			 s = "пят"; break;
		 case '6':
			 s = "шест"; break;
		 case '7':
			 s = "сем"; break;
		 case '8':
			 s = "восем"; break;
		 case '9':
			 s = "девят"; break;
	 }
	 return s + "надцать";
    }		

	public static void main(String[] args){
     System.out.println(new RussianMoney().digits2Text(new Double(args[0])));
    }		
}