Roman numerals solution

roman-numerals-solution/README.md

@@ -0,0 +1,31 @@
+Hi,
+
+
+## Implementation plan
+
+* Create java main class with ability to read input from cmd pipe
+* Implement convert algorithm
+* Catch all possible exceptions
+* Make some refac/add test/finally review
+
+## User guide
+
+1. Compile java source file:
+
+	G:>javac RomanNumeralsConvert.java
+
+2. Run java application with cmd pipe:
+
+	G:>echo "1 12 103" | java RomanNumeralsConvert
+	I
+	XII
+	CIII
+
+3. Add "-test" flag to run application in test mode:
+
+	G:>echo "1 12 103" | java RomanNumeralsConvert -test
+	1 => I passed.
+	12 => XII passed.
+	103 => CIII passed.
+	10char3 => 10char3, illegal argument error - is not valid digital number. passed.
+	10399911 => 10399911, range bound error - number should be in the range [1 - 3999]. passed.

roman-numerals-solution/RomanNumeralsConvert.java

@@ -0,0 +1,175 @@
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.ListIterator;
+import java.util.TreeMap;
+
+public class RomanNumeralsConvert {
+
+	public final static String TEST_MOD = "-test";
+	public final static String ONE = "I";
+	public final static String TWELVE = "XII";
+	public final static String ONE_HUNDRED_AND_THREE = "CIII";
+
+	private final static TreeMap<Integer, String> map = new TreeMap<>();
+	static {
+		map.put(1000, "M");
+		map.put(900, "CM");
+		map.put(500, "D");
+		map.put(400, "CD");
+		map.put(100, "C");
+		map.put(90, "XC");
+		map.put(50, "L");
+		map.put(40, "XL");
+		map.put(10, "X");
+		map.put(9, "IX");
+		map.put(5, "V");
+		map.put(4, "IV");
+		map.put(1, "I");
+	}
+
+	public static void main(String[] args) {
+
+		if (args.length > 0) {
+			if (args.length > 1 || !TEST_MOD.equals(args[0])) {
+				System.out.println("Only one flag supports: - test");
+			}
+
+			runTest();
+
+		} else {
+			final List<String> numbersList = readInput();
+
+			validate(numbersList);
+
+			convert(numbersList);
+
+			printResult(numbersList);
+		}
+
+	}
+
+	private static List<String> readInput() {
+		final List<String> numbersList = new ArrayList<>();
+		try (BufferedReader in = new BufferedReader(new InputStreamReader(System.in))) {
+			String line;
+			while ((line = in.readLine()) != null) {
+				line = line.replace("\"", "").trim();
+				numbersList.addAll(Arrays.asList(line.split("\\s+")));
+			}
+
+		} catch (final IOException e) {
+			System.err.println("IOException reading System.in" + e);
+			System.exit(1);
+		}
+
+		return numbersList;
+	}
+
+	private static void validate(List<String> numbersList) {
+		final ListIterator<String> listIterator = numbersList.listIterator();
+		while (listIterator.hasNext()) {
+			final String numStr = listIterator.next();
+
+			boolean e = true;
+			for (int k = 0; k < numStr.length(); k++) {
+				if (Character.isDigit(numStr.charAt(k)) == false) {
+					listIterator.set(numStr + ", illegal argument error - is not valid digital number.");
+					e = false;
+					break;
+				}
+			}
+
+			if (e) {
+				final int num = Integer.parseInt(numStr);
+				if (num > 3999 || num < 1) {
+					listIterator.set(numStr + ", range bound error - number should be in the range [1 - 3999].");
+				}
+			}
+		}
+	}
+
+	private final static String toRoman(Integer number) {
+		final int l = map.floorKey(number);
+		if (number == l) {
+			return map.get(number);
+		}
+		return map.get(l) + toRoman(number - l);
+	}
+
+	private static void convert(List<String> numbersList) {
+		final ListIterator<String> listIterator = numbersList.listIterator();
+		while (listIterator.hasNext()) {
+			final String numStr = listIterator.next();
+
+			if (numStr.contains("error")) {
+				continue;
+			}
+
+			final Integer num = Integer.valueOf(numStr);
+
+			final int l = map.floorKey(num);
+			if (num == l) {
+				listIterator.set(map.get(num));
+			} else {
+				listIterator.set(map.get(l) + toRoman(num - l));
+			}
+		}
+	}
+
+	public static void printResult(List<String> numbersList) {
+		numbersList.forEach(System.out::println);
+	}
+
+	public static void runTest() {
+		final List<String> numbersList = new ArrayList<>();
+
+		numbersList.add("1");
+		numbersList.add("12");
+		numbersList.add("103");
+		numbersList.add("10char3");
+		numbersList.add("10399911");
+
+		validate(numbersList);
+
+		convert(numbersList);
+
+		System.out.print("1 => " + numbersList.get(0));
+		if (ONE.equals(numbersList.get(0))) {
+			System.out.println(" passed.");
+		} else {
+			System.out.println(" failed.");
+		}
+
+		System.out.print("12 => " + numbersList.get(1));
+		if (TWELVE.equals(numbersList.get(1))) {
+			System.out.println(" passed.");
+		} else {
+			System.out.println(" failed.");
+		}
+
+		System.out.print("103 => " + numbersList.get(2));
+		if (ONE_HUNDRED_AND_THREE.equals(numbersList.get(2))) {
+			System.out.println(" passed.");
+		} else {
+			System.out.println(" failed.");
+		}
+
+		System.out.print("10char3 => " + numbersList.get(3));
+		if ("10char3, illegal argument error - is not valid digital number.".equals(numbersList.get(3))) {
+			System.out.println(" passed.");
+		} else {
+			System.out.println(" failed.");
+		}
+
+		System.out.print("10399911 => " + numbersList.get(4));
+		if ("10399911, range bound error - number should be in the range [1 - 3999].".equals(numbersList.get(4))) {
+			System.out.println(" passed.");
+		} else {
+			System.out.println(" failed.");
+		}
+	}
+}