Question: I am trying to make a program that acts as a thesaurus, it has 3 classes: Entry, Thesaurus, and Proj6 (main method). I have everything
I am trying to make a program that acts as a thesaurus, it has 3 classes: Entry, Thesaurus, and Proj6 (main method). I have everything coded but I am getting a nullPointerException, I am getting it in thesaurus at line 34 (else if (entries[index].addSynonym(syn) == false)), and in my main at line 19(th.addEntry(word, synonyms[i]);) but I am not sure why or how to fix it?
Entry Class:
import java.util.*;
public class Entry {
// Fields:
private String word;
private String[] synonyms;
private int index;
// Constructor:
public Entry(String w) {
word = w;
synonyms = new String[10];
index = 0;
}
// Methods:
public String getWord() {
return word;
}
public boolean addSynonym(String syn) {
if (index == 10) {
return false;
}
if (isSynonym(syn) == true) {
return false;
}
else {
synonyms[index] = syn;
index++;
return true;
}
}
public String getSynonyms() {
StringBuilder sb = new StringBuilder();
for (int i = 0; i < index; i++) {
sb.append(synonyms[i]);
sb.append(",");
}
String syns = sb.toString();
if (syns.length() > 0) {
syns = syns.substring(0, syns.length() - 1);
}
return syns;
}
public boolean isSynonym(String syn) {
for (int i = 0; i < synonyms.length; i++) {
if (synonyms[i].equalsIgnoreCase(syn)) {
return true;
}
}
return false;
}
}
Thesaurus Class:
import java.util.*;
public class Thesaurus {
// Fields:
private Entry[] entries;
private int index;
// Constructor:
public Thesaurus() {
entries = new Entry[7000];
index = 0;
}
private Entry getEntry(String word) {
for (int i = 0; i < index; i++) {
if (entries[i].getWord().equalsIgnoreCase(word)){
return entries[i];
}
}
return null;
}
public boolean addEntry(String word, String syn) {
if (getEntry(word) == null) {
Entry e = new Entry(word);
e.addSynonym(syn);
entries[index] = e;
index++;
return true;
}
if (getEntry(word) != null) {
if (index == entries.length) {
return false;
}
else if (entries[index].addSynonym(syn) == false) {
return false;
}
else if (entries[index].isSynonym(syn) == true) {
return false;
}
else {
entries[index].addSynonym(syn);
}
}
return true;
}
public String lookup(String word) {
if (getEntry(word) != null) {
String synonym = entries[index].getSynonyms();
return synonym;
}
else {
String synonym = entries[index].getWord() + " not found";
return synonym;
}
}
}
Main Method:
import java.util.*;
import java.io.*;
public class Proj6 {
public static void main(String[] args) throws IOException {
Scanner s = new Scanner(System.in);
Scanner inFile = new Scanner(new File("testThesaurus.txt"));
Thesaurus th = new Thesaurus();
while (inFile.hasNext()) {
String line = inFile.nextLine();
StringTokenizer st = new StringTokenizer(line, "[]");
String word = st.nextToken();
int bracketIndex = line.indexOf("]");
String syns = line.substring(bracketIndex + 2);
String[] synonyms = new String[10];
synonyms = syns.split(",");
for (int i = 0; i < synonyms.length; i++) {
th.addEntry(word, synonyms[i]);
}
System.out.println(th.lookup(word));
}
char option;
do {
System.out.print("Enter (l)ookup, (a)dd entry, or (q)uit: ");
option = (s.nextLine().toLowerCase()).charAt(0);
if (option == 'l') {
}
else if (option == 'a') {
}
else {
break;
}
}while (option != 'q');
//System.out.print(th.lookup(word));
}
}
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