import CS342.Hwk3.*;

import java.net.URL;
import java.applet.Applet;
import java.util.Hashtable;
import java.util.Enumeration;
import java.awt.Panel;
import java.awt.TextField;
import java.awt.TextComponent;
import java.awt.Component;
import java.awt.Label;
import java.awt.TextArea;

/**
* This class shows how to use the CS342.Hwk3 package (specifically the
* classes DefaultDisplay and URLTokenizer) to display a file.  This forms
* a basis for the third homework task.
*/
public class Homework3 extends DefaultDisplay {
   	/*----------------------------------------------------------------------*/   
	/**
	* The method defines process_input(String) and so makes this a
	* concrete class that is extending an abstract class.  Notice that
	* we don't need to define either init or handleEvent as they are
	* taken care of in the DefaultDisplay definition.
	*/ 
	public void process_input(String the_url_name) {
		URLTokenizer the_url_tokenizer;
	   	WordCounter the_word_counter = new WordCounter();
		try {
			the_url_tokenizer = new URLTokenizer(the_base_url, the_url_name);
		} catch (URLTokenizerException the_exception) {
			the_text_output.appendText(the_exception.getMessage());
			return; 
		}

		try {
			for(;;) {
				String the_word_just_read = the_url_tokenizer.nextToken();
				if (the_word_just_read.equals("")) {
					the_text_output.appendText(" -- have finished reading " + the_url_name + "\n");
					break;
				}
			   	the_word_counter.add_word(the_word_just_read);
				// the_text_output.appendText(the_word_just_read + "\n");
			}
		} catch(URLTokenizerException the_exception) {
			the_text_output.appendText(the_exception.getMessage());
			return;
		}
	   	try {
		   the_text_output.appendText(" -- The top 10 words are:\n");
		   for (int i = 1 ; i <= 10 ; i++) {
		      the_text_output.appendText(i + ": " + the_word_counter.remove_most_frequent() + "\n");
		   }
		} catch(WordCounterException the_exception) {
		   the_text_output.appendText(the_exception.getMessage() + "\n");
		}
	}
}

/**
 * This exception is thrown if an attempt is made to remove a word from an
 * empty WordCounter.
 */
class WordCounterException extends Exception {
   /*----------------------------------------------------------------------*/
   public WordCounterException() { super(); }
   /*----------------------------------------------------------------------*/
   public WordCounterException(String s) { super(s); }
}


/**
 * This class is used to count the number of times each token appears in the text.
 */
class WordCounter extends Hashtable {      
  
   /*----------------------------------------------------------------------*/
   /**
    * This method adds a new word to the table, or increments the counter on
    * an existing word.  
    */
   public void add_word(String the_word) {
      if (containsKey(the_word))
	put(the_word, new Integer(((Integer) get(the_word)).intValue() + 1));
      else
	put(the_word, new Integer(1));
   }
   
   /*----------------------------------------------------------------------*/
   /**
    * This method removes the word with the hightest count from the table, and
    * returns a string containing the word and its associated count.
    */
   public synchronized String remove_most_frequent() throws WordCounterException {
      String the_current_key, the_maximum_key = "";
      int the_current_value, the_maximum_value = 0;
      Enumeration all_the_keys = keys();
      
      if (!all_the_keys.hasMoreElements()) 
	  throw new WordCounterException("Hmm. There are no more words.");
      
      while (all_the_keys.hasMoreElements()) {
	 the_current_key = (String) all_the_keys.nextElement();
	 the_current_value = ((Integer) get(the_current_key)).intValue();
	 if (the_current_value > the_maximum_value) {
	    the_maximum_value = the_current_value;
	    the_maximum_key =  the_current_key;
	 }
      }
      remove(the_maximum_key);
      return (the_maximum_key + "[" + the_maximum_value + "]");
   }
}