gistfile1.java

/*
Author: Oscar Bell 
Date: 9th May 2014
Description: Program to count the occurrences of words in a string
*/

import java.util.*;
import java.util.Map.Entry;


public class WordOccurrence {

    //-----------------------------------------------------------------------------
    public static Set<String> commonWords = new HashSet<>();
    {
        commonWords.add("the");
        //add other common words here
    }
    //-----------------------------------------------------------------------------

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        String count;
        // Words between quotation marks are the instructions presented in output
        System.out.print("Please enter a string: ");
        count = in.nextLine();
        // Removes punctuation so that words with and without punctuation are counted together
        count = count.replaceAll("[^a-zA-Z ]", "");
        findWordOccurrences(count);
    }

    private static void findWordOccurrences(final String str) {

        // Map containing word usage
        Map<String, Integer> wordArray = new HashMap<>();

        // The array of all words in the string
        String[] allWords;
        // Converts to lower case so words with different cases are counted together
        String essay = str.toLowerCase();
        allWords = essay.split(" ");

        for (String allWord : allWords) {
            Integer count = wordArray.get(allWord);
            // Count won't be null if the word already exists in map

            //-----------------------------------------------------------------------------
            if (count != null) { 
                if (!commonWords.contains(count)) {
            //-----------------------------------------------------------------------------
                    wordArray.put(allWord, count + 1);
                }
            } else {
                wordArray.put(allWord, 1);
            }
        }

        printWordOccurrences(wordArray);
    }

    //Produces table of results    
    private static void printWordOccurrences(Map<String, Integer> wordCount) {
        System.out.println("Word\t\tCount");
        for(Entry<String, Integer> entry : wordCount.entrySet())
        {
            System.out.println(entry.getKey() + "\t\t" + entry.getValue());
        }
    }

}