/**
 * Provides a variety of methods to prompt a user for input.
 * 
 * @author Robert C. Duvall
 */
public class Prompter
{
    //////////////////////////////////////////////////////////////
    // state
    private Scanner myInput;


    //////////////////////////////////////////////////////////////
    // constructors
    /**
     * Create Prompter for that reads user's data from console.
     */
    public Prompter ()
    {
        this(new Scanner());
    }

    /**
     * Create Prompter for that reads user's data from input.
     * 
     * @param input  Scanner that reads delimited data
     */
    public Prompter (Scanner input)
    {
        myInput = input;
        myInput.useDelimiter("\n");
    }


    //////////////////////////////////////////////////////////////
    // accessors
    /**
     * Reads next whole number value without prompting.
     * 
     * @return value entered by user
     */
    public int readInt ()
    {
        return (new Scanner(readLine())).nextInt();
    }
   
    /**
     * Reads next real number value without prompting.
     * 
     * @return value entered by user
     */
    public double readDouble ()
    {
        return (new Scanner(readLine())).nextDouble();
    }

    /**
     * Reads next string without prompting.
     * 
     * @return value entered by user
     */
    public String readString ()
    {
        return (new Scanner(readLine())).nextString();
    }

    /**
     * Reads next string value that ends with newline without prompting.
     * 
     * @return value entered by user
     */
    public String readLine ()
    {
	return myInput.nextString();
    }

    /**
     * Prompts user for data using prompt, then reads next whole number value.
     * 
     * @param prompt text to display to user asking for input
     * 
     * @return value entered by user
     */
    public int promptInt (String prompt)
    {
        System.out.print(prompt);
        return readInt();
    }
   
    /**
     * Prompts user for data using prompt, then reads next real number value.
     * 
     * @param prompt text to display to user asking for input
     * 
     * @return value entered by user
     */
    public double promptDouble (String prompt)
    {
        System.out.print(prompt);
        return readDouble();
    }

    /**
     * Prompts user for data using prompt, then reads next string value.
     * 
     * @param prompt text to display to user asking for input
     * 
     * @return value entered by user
     */
    public String promptString (String prompt)
    {
        System.out.print(prompt);
        return readString();
    }

    /**
     * Prompts user for data using prompt, then reads next string value that ends with new line.
     * 
     * @param prompt text to display to user asking for input
     * 
     * @return value entered by user
     */
    public String promptLine (String prompt)
    {
        System.out.print(prompt);
        return readLine();
    }


    /**
     * Prompts user for data using prompt, then reads next whole number value
     * that falls within range of low and hi inclusive.
     * 
     * @param prompt text to display to user asking for input
     * @param low    smallest possible value user can enter
     * @param hi     largest possible value user can enter
     * 
     * @return value entered by user
     */
    public int promptRange (String prompt, int low, int hi)
    {
        int answer;

        do
        {
            answer = promptInt(prompt + " between " + low + " and " + hi + "? ");
        }
        while (low > answer || answer > hi);

        return answer;
    }

    /**
     * Prompts user for data using prompt, then reads next real number value
     * that falls within range of low and hi inclusive.
     * 
     * @param prompt text to display to user asking for input
     * @param low    smallest possible value user can enter
     * @param hi     largest possible value user can enter
     * 
     * @return value entered by user
     */
    public double promptRange (String prompt, double low, double hi)
    {
        double answer;

        do
        {
            answer = promptDouble(prompt + " between " + low + " and " + hi + "? ");
        }
        while (low > answer || answer > hi);

        return answer;
    }

    /**
     * Prompts user for data using prompt, expected to be a yes/no question, 
     * then returns true if user answered yes, false otherwise
     * 
     * @param prompt yes/no question to display to user asking for input
     */
    public boolean promptYesNo (String prompt)
    {
        String answer;

        do
        {
            answer = promptString(prompt + " (yes or no)? ");
        }
        while (!answer.equals("yes") && !answer.equals("no"));

        return (answer.equals("yes"));
    }


    //////////////////////////////////////////////////////////////
    // Main
    // Allow this class to be run directly by Java.
    // Read data from user and echo it back until user enters just a "."
    public static void main (String args[])
    {
        Prompter prompter = new Prompter();

        // read number at a time
        int num;
        do
	{
            num = prompter.readInt();
            System.out.print("**" + num + "**\n");
	}
	while (num != 0);

        // read word at a time
        String word;
        do
        {
            word = prompter.readString();
            System.out.print("**" + word + "**\n");
        }
        while (! word.equals("."));

        // read a line at a time
        while (true)
        {
            String response = prompter.promptLine("Enter keywords to search for: ");
            if (response.equals("."))
            {
                break;
            }
            else
            {
		System.out.print("**" + response + "**\n");
	    }
	}
    }
}