ChallengeTwo.java

class Challenge {
  
    private static String hashes;
	private static String content;
	private static int numHashes;
	
	/*
	 * Parses input markdown into HTML header format
	 * @Param String markdown - String holding markdown string for converstion
	 * @Return String output - HTML format of input markdown
	 */
	public static String markdownParser( String markdown )
	{
		//Initalise values 
		hashes = "";
		content = "";
		numHashes = 0;
		
		System.out.println("Input markdown: '" + markdown + "'");
		
		//Trim markdown to remove leading spaces
		markdown = markdown.trim();
		
		//Check markdown input is valid before proceeding
		if(checkInputValid(markdown))
		{
			System.out.println("Input valid");
			
			//Split string into hashes and content
			splitString(markdown);
			
			
			String output = constructOutput();
			System.out.println("\n");
			return output;
		}
		else
		{
			System.out.println("Input not valid\n");
			return markdown;
		}
		
		
	}
	
	/*
	 * Checks to ensure markdown input is valid
	 * Checks for: 
	 *  - First character in string is #
	 *  - String contains " " 
	 *  - Number of hashes does not exceed 6
	 *  
	 *  @Param String input - String holding input markdown to be checked
	 *  @Return boolean inputValid
	 */
	public static boolean checkInputValid(String input)
	{
		boolean inputValid = true;
		
		//Get value of first character in string 
		String firstChar = input.substring(0, 1);
		System.out.println("First char in string " + input + ": " + firstChar);
		
		//Checks for presence of # and whitespace within input
		if(firstChar.matches("#") && input.contains(" "))
		{
			inputValid = true;
		}
		else if(!firstChar.matches("#")) //If # is not present, input is invalid
		{
			System.out.println("Input markdown does not contain '#' as first character");
			inputValid = false;
		}
		else //If whitespace is not present, input is invalid
		{
			System.out.println("Input markdown does not contain ' ' within string");
			inputValid = false;
		}
		
		//Count number of hashes present in input string
		int countHashes = input.length() - input.replace("#", "").length();
		
		if(countHashes > 6)
		{
			System.out.println("Input string contains more than 6 hashes.");
			inputValid = false;
		}

		
		return inputValid;
	}

	/*
	 * Splits the input markdown string into two strings representing hashes and content
	 * @Param String input - Input string representing markdown to be split
	 * @Return void 
	 */
	public static void splitString(String input)
	{
		//Find index of space within input
		int space = input.indexOf(" ");
		
		//Split the string into hashes and content using the index of the string
		hashes = input.substring(0, space);
		content = input.substring(space+1, input.length());
		
		//Trim leading spaces from both hashes and content
		hashes = hashes.trim();
		content = content.trim();
		
		numHashes = hashes.length();
		
		System.out.println("Hashes: " + hashes);
		System.out.println("Content: " + content);
		
	}
	
	/*
	 * Constructs the output using the hashes and content strings produced by the splitSplit method
	 * @Param void
	 * @Return String output - String representation of HTML header 
	 */
	public static String constructOutput()
	{
		String output = "<h";
		output = output + Integer.toString(numHashes) + ">";
		output = output + content;
		output = output + "</h" + Integer.toString(numHashes) + ">";
		
		System.out.println("Output:" +  output);
		return output;
	}
	
	
}