Suggested Solution to HW #7 CSCI 4230, Fall 2001

CSCI 4230
Software Tools
Fall 2001
Suugested Solution to Homework #7

(1) For example,

//
//   SameCharSets.java
//
//   This servlet accept a set of characters and search a Unix dictionary
//   to find all words that can be constructed by using exactly all
//   characters in the set.
//
import java.io.*;
import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;

public class SameCharSets extends HttpServlet {
private boolean DEBUG = false;

String dictionaryFileName = "your_physical_directly\\words.txt";
Properties charSets = new Properties();

public void init(ServletConfig config) throws ServletException {
super.init(config);

    // Try to load the word file to populate the Properties charSets,
    // key is a set of character in alphebetical order.
    // value is the list of all words constructed by using all char
    // in the set.
    try {
      FileReader fileReader = new FileReader(dictionaryFileName);
      BufferedReader bufferedReader = new BufferedReader(fileReader);
      String inline = null;
      String key;
      while ((inline = bufferedReader.readLine()) != null) {
         // process a line.
         // Prepare key = inline in sorted alphabetical order. Use snail sort.
         key = sortWord(inline);
         if (charSets.getProperty(key) == null) {
             charSets.put(key, inline);
         }
         else {
             charSets.put(key, charSets.getProperty(key) + ", " + inline);
         }
      }
    }
    catch (FileNotFoundException ignored) { }
    catch (IOException ignored) { }
    catch (NumberFormatException ignored) { }
}

public void doGet(HttpServletRequest request, HttpServletResponse response)
                               throws ServletException, IOException {
    response.setContentType("text/html");
    PrintWriter out = response.getWriter();

     // get the parameter value of word.
    String word = request.getParameter("word");
    String result;

    if (word == null) { // Print initial instruction and form.
       out.println("<HTML>");
       out.println("<HEAD><TITLE>Word Constructor</TITLE></HEAD>");
       out.println("<BODY BGCOLOR=#CCCCFF>");
       out.println("<H2 STYLE='COLOR:Blue'>Jumbo Word Constructor</H2>");
       out.println("This application allows you to enter characters and ");
       out.println("output words that are constructed of exactly these ");
       out.println("characters. For example, if you enter 'lpoo', it");
       out.println("will output 'loop', 'pool', 'polo', but not 'lop'.");
       out.println("The program uses a simple Unix dictionary.");
       printForm(out);
       out.println("</BODY></HTML>");
     }
     else if ((result = charSets.getProperty(sortWord(word.toLowerCase()))) == null) {
        // no word found.
        out.println("<HTML>");
        out.println("<HEAD><TITLE>Words not found.</TITLE></HEAD>");
        out.println("<BODY BGCOLOR=#CCCCFF>");
        out.println("<H2 STYLE='COLOR:Blue'>Jumbo Word Constructor: Not found</H2>");
        out.println("Sorry, no word can be found for the characters: ");
        out.println("<SPAN STYLE='COLOR:Blue'>" + word + "</SPAN><P>");
        printForm(out);

        if (DEBUG) {
           for (Enumeration e= charSets.propertyNames(); e.hasMoreElements(); ) {
               String key = (String) e.nextElement();
               out.println(key + " ==> " + charSets.getProperty(key) + "<BR>");
           }
        }

        out.println("</BODY></HTML>");
     }
     else { // print result.
        out.println("<HTML>");
        out.println("<HEAD><TITLE>Words found.</TITLE></HEAD>");
        out.println("<BODY BGCOLOR=#CCCCFF>");
        out.println("<H2 STYLE='COLOR:Blue'>Jumbo Word Constructor: Result</H2>");
        out.println("For the characters: ");
        out.println("<SPAN STYLE='COLOR:Blue'>" + word + "</SPAN>, ");
        out.println("the following words are found: ");
        out.println("<SPAN STYLE='COLOR:Blue'>" + result + "</SPAN>.");
        printForm(out);
        out.println("</BODY></HTML>");
     }
}

public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}

private static void printForm(PrintWriter out) {
     out.println("<FORM METHOD='GET'>");
     out.println("Please enter your characters (no space in between):<P>");
     out.println("<INPUT TYPE=TEXT SIZE=10 NAME=word>");
     out.println("    ");
     out.println("<INPUT TYPE=SUBMIT>");
     out.println("</FORM>");
}

// sort the word inline in alphabetical order using snail sort.
private String sortWord(String inline) {
    char[] temp;
    char tempchar;
    temp = inline.toLowerCase().toCharArray();
    for (int i=0; i<temp.length-1; i++) {
        for (int j=i+1; j<temp.length; j++) {
            if (temp[i] > temp[j]) {
                tempchar = temp[i];
                temp[i] = temp[j];
                temp[j] = tempchar;
            }
        }
    }
    return String.valueOf(temp);
}
}