programming-examples/java/_Basics/WordCount (Java).java

//Program  that compares counting words in files using an ArrayList and a Map.

import java.io.File;
import java.io.FileNotFoundException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Scanner;

import javax.swing.JFileChooser;
import javax.swing.UIManager;


public class WordCount
{

    public static void main(String[] args)
    {
        countWordsViaGUI();
    }


    // allow user to pick file to exam via GUI.
    // allow multiple picks
    public static void countWordsViaGUI()
    {
        setLookAndFeel();
        try
            {
                Scanner key = new Scanner(System.in);
                do
                    {
                        System.out.println("Opening GUI to choose file.");
                        Scanner fileScanner = new Scanner(getFile());
                        Stopwatch st = new Stopwatch();
                        st.start();
                        ArrayList<String> words = countWordsWithArrayList(fileScanner);
                        st.stop();
                        System.out.println("time to count: " + st);
                        System.out.print("Enter number of words to display: ");
                        int numWordsToShow = Integer.parseInt(key.nextLine());
                        showWords(words, numWordsToShow);
                        fileScanner.close();
                        System.out.print("Perform another count? ");
                    }
                while(key.nextLine().toLowerCase().charAt(0) == 'y');
                key.close();
            }
        catch(FileNotFoundException e)
            {
                System.out.println("Problem reading the data file. Exiting the program." + e);
            }
    }


    // determine distinct words in a file using an array list
    private static ArrayList<String> countWordsWithArrayList(Scanner fileScanner)
    {
        System.out.println("Total number of words: " + numWords);
        System.out.println("number of distincy words: " + result.size());
        return result;
    }


    // determine distinct words in a file and frequency of each word with a Map
    private static Map<String, Integer> countWordsWithMap(Scanner fileScanner)
    {
        System.out.println("Total number of words: " + numWords);
        System.out.println("number of distincy words: " + result.size());
        return result;
    }


    private static void showWords(ArrayList<String> words, int numWordsToShow)
    {
        for(int i = 0; i < words.size() && i < numWordsToShow; i++)
            System.out.println(words.get(i));
    }


    private static void showWords(Map<String, Integer> words, int numWordsToShow)
    {
    }


    // perform a series of experiments on files. Determine average time to
    // count words in files of various sizes
    private static void performExp()
    {
        String[] smallerWorks = {"smallWords.txt", "2BR02B.txt", "Alice.txt", "SherlockHolmes.txt"};;
        String[] bigFile = {"ciaFactBook2008.txt"};
        timingExpWithArrayList(smallerWorks, 50);
        timingExpWithArrayList(bigFile, 3);
        timingExpWithMap(smallerWorks, 50);
        timingExpWithMap(bigFile, 3);
    }


    // pre: titles != null, elements of titles refer to files in the
    // same path as this program, numExp >= 0
    // read words from files and print average time to cound words.
    private static void timingExpWithMap(String[] titles, int numExp)
    {
        try
            {
                double[] times = new double[titles.length];
                final int NUM_EXP = 50;
                for(int i = 0; i < NUM_EXP; i++)
                    {
                        for(int j = 0; j < titles.length; j++)
                            {
                                Scanner fileScanner = new Scanner(new File(titles[j]));
                                Stopwatch st = new Stopwatch();
                                st.start();
                                Map<String, Integer> words = countWordsWithMap(fileScanner);
                                st.stop();
                                System.out.println(words.size());
                                times[j] += st.time();
                                fileScanner.close();
                            }
                    }
                for(double a : times)
                    System.out.println(a / NUM_EXP);
            }
        catch(FileNotFoundException e)
            {
                System.out.println("Problem reading the data file. Exiting the program." + e);
            }
    }


    // pre: titles != null, elements of titles refer to files in the
    // same path as this program, numExp >= 0
    // read words from files and print average time to cound words.
    private static void timingExpWithArrayList(String[] titles, int numExp)
    {
        try
            {
                double[] times = new double[titles.length];
                for(int i = 0; i < numExp; i++)
                    {
                        for(int j = 0; j < titles.length; j++)
                            {
                                Scanner fileScanner = new Scanner(new File(titles[j]));
                                Stopwatch st = new Stopwatch();
                                st.start();
                                ArrayList<String> words = countWordsWithArrayList(fileScanner);
                                st.stop();
                                times[j] += st.time();
                                fileScanner.close();
                            }
                    }
                for(int i = 0; i < titles.length; i++)
                    System.out.println("Average time for " + titles[i] + ": " + (times[i] / numExp));
            }
        catch(FileNotFoundException e)
            {
                System.out.println("Problem reading the data file. Exiting the program." + e);
            }
    }


    // try to set look and feel to same as system
    private static void setLookAndFeel()
    {
        try
            {
                UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
            }
        catch(Exception e)
            {
                System.out.println("Unable to set look at feel to local settings. " +
                                   "Continuing with default Java look and feel.");
            }
    }


    /** Method to choose a file using a window.
     * @return the file chosen by the user. Returns null if no file picked.
     */
    private static File getFile()
    {
        // create a GUI window to pick the text to evaluate
        JFileChooser chooser = new JFileChooser(".");
        chooser.setDialogTitle("Select File To Count Words:");
        int retval = chooser.showOpenDialog(null);
        File f =null;
        chooser.grabFocus();
        if (retval == JFileChooser.APPROVE_OPTION)
            f = chooser.getSelectedFile();
        return f;
    }
}