Use the following files:

DataSet.java

/**
   Computes the average of a set of data values.
*/
public class DataSet
{
   /**
      Constructs an empty data set with a given measurer.
      @param aMeasurer the measurer that is used to measure data values
   */
   public DataSet(Measurer aMeasurer)
   {
      sum = 0;
      count = 0;
      maximum = null;
      measurer = aMeasurer;
   }

   /**
      Adds a data value to the data set.
      @param x a data value
   */
   public void add(Object x)
   {
      sum = sum + measurer.measure(x);
      if (count == 0 
            || measurer.measure(maximum) < measurer.measure(x))
         maximum = x;
      count++;
   }

   /**
      Gets the average of the added data.
      @return the average or 0 if no data has been added
   */
   public double getAverage()
   {
      if (count == 0) return 0;
      else return sum / count;
   }

   /**
      Gets the largest of the added data.
      @return the maximum or 0 if no data has been added
   */
   public Object getMaximum()
   {
      return maximum;
   }

   private double sum;
   private Object maximum;
   private int count;
   private Measurer measurer;
}

Measurer.java

/**
   Describes any class whose objects can measure other objects.
*/
public interface Measurer
{
   /**
      Computes the measure of an object.
      @param anObject the object to be measured
      @return the measure
   */
   double measure(Object anObject);
}

Word.java

/**
   This class describes words in a document.
*/
public class Word
{
   /**
      Constructs a word by removing leading and trailing non-
      letter characters, such as punctuation marks.
      @param s the input string
   */
   public Word(String s)
   {
      int i = 0;
      while (i < s.length() && !Character.isLetter(s.charAt(i)))
         i++;
      int j = s.length() - 1;
      while (j > i && !Character.isLetter(s.charAt(j)))
         j--;
      text = s.substring(i, j + 1);      
   }

   /**
      Returns the text of the word, after removal of the
      leading and trailing non-letter characters.
      @return the text of the word
   */
   public String getText()
   {
      return text;
   }

   /**
      Counts the syllables in the word.
      @return the syllable count
   */
   public int countSyllables()
   {
      int count = 0;
      int end = text.length() - 1;
      if (end < 0) return 0; // The empty string has no syllables

      // An e at the end of the word doesn't count as a vowel
      char ch = Character.toLowerCase(text.charAt(end));
      if (ch == 'e') end--;

      boolean insideVowelGroup = false;
      for (int i = 0; i <= end; i++)
      {
         ch = Character.toLowerCase(text.charAt(i));
         String vowels = "aeiouy";
         if (vowels.indexOf(ch) >= 0) 
         {
            // ch is a vowel
            if (!insideVowelGroup)
            {
               // Start of new vowel group
               count++; 
               insideVowelGroup = true;
            }
         }
         else insideVowelGroup = false;
      }

      // Every word has at least one syllable
      if (count == 0) 
         count = 1;

      return count;      
   }

   private String text;
}

WordMeasurerTester.java

/**
   This program tests the WordMeasurer class.
*/
public class WordMeasurerTester
{
   public static void main(String[] args)
   {
      DataSet data = new DataSet(new WordMeasurer());

      data.add(new Word("Java"));
      data.add(new Word("is"));
      data.add(new Word("an"));
      data.add(new Word("object"));
      data.add(new Word("oriented"));
      data.add(new Word("programming"));
      data.add(new Word("language"));

      System.out.println("Average measure: " 
            + data.getAverage());
      System.out.println("Expected: 2.0");
   }
}