// adapted from Liang's "CountOccurrenceOfWords" example
// (see my GUI notes for info on book)
import java.util.*;

public class CountWords {
    public static void main(String[] args) {
    
	// Text in a string with words to count:
	String text = "aaa bbb aaa bbb bbb ccc ddd";
	
	// Create a hash map;
	// keys=words, values=counts:
   	HashMap hashMap = new HashMap();
	
	// Split text into individual words to
	// produce keys; use space (" ") to tokenize:
	StringTokenizer allKeys = 
	    new StringTokenizer(text);

	// For each word in text,
	// if it's "old", increment count
	// otherwise, create a key and start count
	while (allKeys.hasMoreTokens()) {
	    
	    // Current word to test:
	    String key = allKeys.nextToken();

	    // Increment count if key's already in hm
	    // (I split this up for clarity):
	    if (hashMap.get(key) != null) {

		// Retrieve val corresponding to key:
		Object val = hashMap.get(key);

		// Create new value to store:
		int intVal = ((Integer)val).intValue();

		// Increment value:
		intVal++;

		// Store it:
		hashMap.put(key, new Integer(intVal));

	    } else {

		// Create new key-value for hm:
		hashMap.put(key, new Integer(1));
	    }

	} // done creating hm
    
	// Create a tree map from the hash map:
	TreeMap treeMap = new TreeMap(hashMap);
	
	// Get an entry set for the tree map:
	Set entrySet = treeMap.entrySet();

	// Get an iterator for the entry set:
	Iterator iterator = entrySet.iterator();

	// Display mappings:
	System.out.println("Words and counts in " +
			   "ascending order of words:");
	while (iterator.hasNext()) {
	    System.out.println(iterator.next());
	}

    } // end main
    
} // Class CountWords

/* output:
   Words and counts in ascending order of words:
   aaa=2
   bbb=3
   ccc=1
   ddd=1
*/