Overview:

The program will create a Servlet that will respond to HTML requests with text streams. The servlet will have locally instantiated Expert System object. The website will allow a user to see results from the Expert System or add new data to the Expert System.

Specifics:

index.html Webpage that allows the user to select a link to go to the using page or a link to go to the training page. These buttons / links will call the servlet. The servlet will serve up either using.jsp (with appropriate data) or training.jsp.

using.jsp Webpage that allows the user to query the Expert System using a drop down list of key words. Initially this page has no results, only the drop down list and a button. The button click will call the servlet. The servlet will serve up using.jsp with appropriate data. This page will also a button to go to the training page.

training.jsp Webpage that allows the user to update the Expert System using two text fields. One is a key that may or may not already be in the Expert System. The other is a new value. The button click will call the servlet. The servlet will either add to an existing keys values (if the key already exists) or will add a new key / value pair. The servlet will serve up the training.jsp page. This page will also a button to go to the using page.

DataServlet.java The servlet class that manages all of the requests and responses.

here is the program:

package expertsystem;

import java.io.BufferedReader;

import java.io.BufferedWriter;

import java.io.File;

import java.io.FileReader;

import java.io.FileWriter;

import java.io.InputStream;

import java.io.InputStreamReader;

import java.io.OutputStream;

import java.io.PrintWriter;

import java.util.ArrayList;

import java.util.HashMap;

import java.util.Random;

import java.util.Scanner;

public class ExpertSystemData {

private HashMap data; // stores all key value pairs

private String fileName; // name of the input and output file

private Random rand; // random object to randomly select a

public ExpertSystemData (String fn) {

data = new HashMap();

fileName = fn;

rand = new Random();

readFile( );

}

public String getValue(String key) {

// method returns a single random value associated with this key

// returns null if key is not found

String allValues = data.get(key);

if (allValues == null) {

return null;

}

// split result into individual elements (split on comma)

String[] tokens = allValues.split(",");

return tokens[rand.nextInt(tokens.length)];

}

public String getValues(String key) {

// method returns all values associated with this key

// returns null if key is not found

String allValues = data.get(key);

if (allValues == null) {

return null;

}

return allValues;

}

public boolean hasKey (String key) {

// method determines if the key exists in the hashmap

return data.containsKey(key);

}

public ArrayList getKeysForValue (String value) {

// method returns all of the keys with input value

// if value is not found the returned ArrayList will be empty

ArrayList toReturn = new ArrayList();

for (String key : data.keySet()) {

if (data.get(key).contains(value))

toReturn.add(key);

}

return toReturn;

}

public ArrayList getAllKeys () {

// method returns all of the keys in the hashmap

ArrayList toReturn = new ArrayList();

for (String key : data.keySet()) {

toReturn.add(key);

}

return toReturn;

}

public void addToKey (String key, String value) {

// this method adds input value to input key

// if the key exists, the value is appended to the existing values

// if the key does not exist, the new key / value pair is added to the hashmap

String currentValues = data.get(key);

if (currentValues == null) {

currentValues = value;

}

else {

currentValues += ","+value;

}

data.put(key, currentValues);

}

public String toString () {

return data.toString();

}

private void doWrite(String fn) {

// this method writes all of the data in the hashmap to the file set during

// creation of this object

try

{

FileWriter fw = new FileWriter(fn);

BufferedWriter myOutfile = new BufferedWriter(fw);

// format for write will be key:value

for (String key : data.keySet()) {

myOutfile.write(key+":"+data.get(key)+" ");

}

myOutfile.flush();

myOutfile.close();

}

catch (Exception e) {

e.printStackTrace();

System.err.println("Didn't save to " + fn);

}

}

public void writeFile () {

// overloaded method: this calls doWrite with file used to read data

// use this for saving data between runs

doWrite(fileName);

} // end of writeFile method

public void writeFile(String altFileName) {

// overloaded method: this calls doWrite with different file name

// use this for testing write

doWrite(altFileName);

}// end of writeFile method

private void readFile( ){

// this method reads all of the data in the file and stores it into the

// hashmap as a key value pair

try

{

// FileReader fr = new FileReader(fileName);

// BufferedReader myInfile = new BufferedReader(fr);

InputStream inp = getClass().getResourceAsStream(fileName);

BufferedReader myInfile = new BufferedReader(new InputStreamReader(inp));

String line;

while ((line = myInfile.readLine()) != null) {

// format from read will be key:value

System.out.println(line);

String[] tokens = line.split(":");

data.put(tokens[0], tokens[1]);

}

}

catch (Exception e) {System.err.println("Didn't read from " + fileName);}

} // end of readFile

}

package expertsystem;

public class Tester {

public static void main(String[] args) {

ExpertSystemData expert = new ExpertSystemData("/expertsystem/data.txt");

System.out.println(expert+" ");

// test hasKey

if(expert.hasKey("ground meat")) {

System.out.println("ground meat is one of the ingredients ");

}

else {

System.out.println("ground meat is NOT one of the ingredients ");

}

if(expert.hasKey("jelly fish")) {

System.out.println("jelly fish is one of the ingredients ");

}

else {

System.out.println("jelly fish is NOT one of the ingredients ");

}

// test getAllKeys

System.out.println("print all keys " + expert.getAllKeys()+" ");

// test getValue

System.out.println("print a recipe with lemon " + expert.getValue("lemon")+" ");

// test getValues

System.out.println("print all recipes with salmon " + expert.getValues("salmon")+" ");

// test getKeysForValue

System.out.println("print ingredients in lemon dishes " + expert.getKeysForValue("lemon")+" ");

// test adding to expert

// add to existing ingredient

expert.addToKey("salmon", "pate");

System.out.println("print all recipes with salmon " + expert.getValues("salmon")+" ");

// add to new ingredient

expert.addToKey("peanut butter", "pb&j");

System.out.println("print all recipes with peanut butter " + expert.getValues("peanut butter")+" ");

// add to previously new ingredient

expert.addToKey("peanut butter", "peanut butter cookies");

System.out.println("print all recipes with peanut butter " + expert.getValues("peanut butter")+" ");

// write data to tester file

expert.writeFile("./expertsystem/dataTest.txt");

}

}

data.txt

salmon:burgers,baked with lemons,smoked salmon

ground meat:hamburgers,spaghetti,meat loaf

broccoli:steamed with lemons,fried,baked with cardamom

lemon:steamed broccoli with lemons,baked fish,lemon sorbet