import java.io.File;
import java.io.FileNotFoundException;
import java.util.ArrayList;
import java.util.Scanner;

/**
 * @author gtowell
 * file: UniqueWords.java
 * Created: Sep 12, 2019
 * Desc:
 *    Read a file then print a list of the unique words contained in that file.
 *    Words are defined as sinly sets of characters separated by whitespace.
 **/ 
public class UniqueWords
{
    
    public static void main(String[] args)
    {
	UniqueWords wc = new UniqueWords();
	wc.uniquer("UniqueWords.java");
    }

    /**
     * Open a file and read it word by word
     * @param filename the name of the file to be opened
     * No return value,  rather the result is the side-effect of printing the list of words in the given file
     **/
    void uniquer(String filename)
    {
	ArrayList<String> wordS = new ArrayList<>();
	try (Scanner input=new Scanner(new File(filename))){            
	    while (input.hasNextLine()) { // test if there is a line to read
		String line = input.nextLine();
		Scanner s2 = new Scanner(line); 
		while (s2.hasNext())
		{
		    String w = s2.next();
		    if (!findWord(w, wordS))
		    {
			wordS.add(w);
		    }
		}	
		s2.close();
	    }
	
	} 
	catch (FileNotFoundException e) {
		System.err.println("Error in opening the file:" + filename);
		System.exit(1);
	}
	for (String w : wordS)
	{
	    System.out.println(w);
	}
    }

    /**
     * Check arraylist for a word
     * @param w the word to be looked for
     * @param words the array list to be check
     * @return true iff the arraylist contains the word
     **/
    private boolean findWord(String w, ArrayList<String> words)
    {
	for (String ww : words)
	{
	    if (w.equals(ww))
		return true;
	}
	return false;
    }
    

}