// CSE 143, Winter 2010, Marty Stepp
//
// This program counts the number of words in a large file.
// It demonstrates the use of a Set collection.

import java.io.*;
import java.util.*;

// list    -> 22021 ms
// hashset ->   882 ms
// treeset ->  1051 ms

public class SetWordCount {
    public static void main(String[] args) throws FileNotFoundException {
        // store a set of of each word seen so far (faster than a list)

        // List<String> words = new ArrayList<String>();
        Set<String> words = new TreeSet<String>();
        
        long start = System.currentTimeMillis();
        
        System.out.println("Reading file...");
        Scanner input = new Scanner(new File("mobydick.txt"));
        while (input.hasNext()) {
            String word = input.next();
            
            // if you wanted to remove punctuation and ignore case, you could say:
            // word = word.toLowerCase().replaceAll("[^a-z]", "");
            
            // don't need to call contains because set already ignores duplicates
            // if (!words.contains(word)) { ...
            
            words.add(word);
        }
        
        long end = System.currentTimeMillis();
        long elapsed = end - start;
        
        System.out.println("The file has " + words.size() + " words.");
        System.out.println("Took " + elapsed + " ms.");
        
        // sets don't have indexes, so you can't use a "for int i" loop
        // for (int i = 0; i < words.size(); i++) {
        
        // instead, use a "for-each" loop
        // for (String word : words) {
            // System.out.println(word);
        // }
        
        
        // use an iterator to loop over the elements and filter out some of them
        Iterator<String> itr = words.iterator();
        while (itr.hasNext()) {
            String word = itr.next();
            if (word.length() <= 3) {
                // have to call remove on the iterator, not on the set
                // words.remove(word);
                
                itr.remove();
            }
        }
        System.out.println("The file has " + words.size() + " words.");
    }
}