Develop Reference

My code is not reading my text file and it has an exception which is not letting me save an object. How do I fic it?

I have code that basically reads the file and stores it in an object.
I'm having issues when trying to turn one of the String in the array into int/double etc.
I'm using a linked list to save the object.
I have tried debugging but I can't find the issue. The program runs fine and dandy until it reaches the changing of variables part. No matter what I do, what I change, or how I try to fix it the same exception occurs. And then sometimes when it works it doesn't save it.
private void readFile() {
BufferedReader in;
String line = "";
try {
in = new BufferedReader(new FileReader("Doggie.txt"));//file name
try {
line = in.readLine();
} catch (Exception e) {
line = null;
}
while (line != null) {
String[] lineArray = line.split(",");
String name = lineArray[0];
String a = lineArray[1];
String phone = lineArray[2];
String location = lineArray[3];
String p = lineArray[4];
String id = lineArray[5];
String dogName = lineArray[6];
String breed = lineArray[7];
String w = lineArray[8];
String t = lineArray[9];
String vet = lineArray[10];
int age = Integer.parseInt(a);
double payment = Double.parseDouble(p);
double weight = Double.parseDouble(w);
int times = Integer.parseInt(t);
Dog doggo = new Dog(name, phone, location, payment, id, dogName, breed, age, weight, times, vet);
dogsList.addNode(doggo);
try {
line = in.readLine();
} catch (Exception e) {
line = null;
}
}
DogsLoaded = true;
} catch (Exception e) {
JOptionPane.showMessageDialog(this, "Error opening files, please check the information provided", "Error!", JOptionPane.ERROR_MESSAGE);
}
}

In the loop I do not see a repetition of readLine, a bug.
Evidently you need input validation and better error reporting.
Data errors may be hard to find, so line content and line number might be benificial.
I added some validation, but it can be done nicer.
I gave the cryptic Exception.getMessage (or getLocalizedMessage), as that at least will inform you to the cause.
String message = "";
int lineno = 0;
try (BufferedReader in = Files.newBufferedReader(
Paths.get("Doggie.txt"), Charset.defaultCharset())) {
String line;
while ((line = in.readLine())!= null) {
++lineno;
String[] lineArray = line.split("\\s*,\\s*");
Above I allowed whitespace around the comma. This trims the fields, which otherwise would not be able to be converted to a number.
Checking the number of fields is important; for instance the name could contain a comma.
if (lineArray.length != 11) {
throw new IllegalArgumentException("Wrong number of fields: " + line);
}
String name = lineArray[0];
String a = lineArray[1];
String phone = lineArray[2];
String location = lineArray[3];
String p = lineArray[4];
String id = lineArray[5];
String dogName = lineArray[6];
String breed = lineArray[7];
String w = lineArray[8];
String t = lineArray[9];
String vet = lineArray[10];
The following conversions seem to go wrong, give a NumberFormatException probably.
You certainly want to know the source.
message = "Age wrong: " + lineno + ". " +line;
int age = Integer.parseInt(a);
message = "Payment wrong: " + lineno + ". " +line;
double payment = Double.parseDouble(p);
message = "Weight wrong: " + lineno + ". " +line;
double weight = Double.parseDouble(w);
message = "Times wrong: " + lineno + ". " +line;
int times = Integer.parseInt(t);
message = "";
Dog doggo = new Dog(name, phone, location, payment,
id, dogName, breed, age, weight, times, vet);
dogsList.addNode(doggo);
}
DogsLoaded = true;
} catch (Exception e) {
if (message.isEmpty()) {
message = e.getMessage()
}
JOptionPane.showMessageDialog(this,
"Error opening files: " + message,
"Error", JOptionPane.ERROR_MESSAGE);
}
Additionally I used Files with Paths and Path, which is the swiss knife utility to go with.
The try-with-resources-syntax ensures that the file is closed also on exception or return.
Files has also functions for reading all lines, writing all lines, reading in a Stream of lines.

Separate into column without using split function

I am trying to separate these value into ID, FullName and Phone. I know we can split it by using java split function. But is there any other ways to separate it? Values:
1 Peater John 2522523254
10 Neal Tom 2522523254
11 Tom Jackson 2522523254
111 Jack Smith 2522523254
12 Brownson Black 2522523254
I tried to use substring method but it won't work properly.
String id = line.substring(0, 3);
If I do this then it will work till 4th line, but other won't work properly.

If it is fixed length you can use String.substring(). But you should also trim() the result before you try to convert it to numeric:
String idTxt=line.substring(0,4);
Long id=Long.parseLong(idTxt.trim());
String name=line.substring(5,25).trim(); // or whatever the size is of name column.

You can use regex and Pattern
Pattern pattern = Pattern.compile("(\\d*)\s*([\\w\\s]*)\\s*(\\d*)");
Matcher matcher = pattern.matcher(content);
if (matcher.find()) {
string id = matcher.group(0);
string name = matcher.group(1);
string phone = matcher.group(2);
}

package Generic;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
class Main
{
public static void main(String[] args)
{
String txt=" 12 Brownson Black 2522523254";
String re1=".*?"; // Non-greedy match on filler
String re2="(\\d+)"; // Integer Number 1
String re3="(\\s+)"; // White Space 1
String re4="((?:[a-z][a-z]+))"; // Word 1
String re5="(\\s+)"; // White Space 2
String re6="((?:[a-z][a-z]+))"; // Word 2
String re7="(\\s+)"; // White Space 3
String re8="(\\d+)"; // Integer Number 2
Pattern p = Pattern.compile(re1+re2+re3+re4+re5+re6+re7+re8,Pattern.CASE_INSENSITIVE | Pattern.DOTALL);
Matcher m = p.matcher(txt);
if (m.find())
{
int id = Integer.parseInt(m.group(1));
String name =m.group(3) + " ";
name = name+m.group(5);
long phone = Long.parseLong(m.group(7));
System.out.println(id);
System.out.println(name);
System.out.println(phone);
}
}
}

What about this:
int first_space;
int last_space;
first_space = my_string.indexOf(' ');
last_space = my_string.lastIndexOf(' ');
if ((first_space > 0) && (last_space > first_space))
{
long id;
String full_name;
String phone;
id = Long.parseLong(my_string.substring(0, first_space));
full_name = my_string.substring(first_space + 1, last_space);
phone = my_string.substring(last_space + 1);
}

Use a regexp:
private static final Pattern RE = Pattern.compile(
"^\\s*(\\d+)\\s+(\\S+(?: \\S+)*)\\s+(\\d+)\\s*$");
Matcher matcher = RE.matcher(s);
if (matcher.matches()) {
System.out.println("ID: " + matcher.group(1));
System.out.println("FullName: " + matcher.group(2));
System.out.println("Phone: " + matcher.group(3));
}

You can use a StringTokenizer for this. You won't have to worry about amount of spaces and/or tabs before or after your values, and no need for complex regex expressions:
String line = " 1 Peater John\t2522523254 ";
StringTokenizer st = new StringTokenizer(line, " \t");
String id = "";
String name = "";
String phone = "";
// The first token is your id, you can parse it to an int if you like or need it
if(st.hasMoreTokens()) {
id = st.nextToken();
}
// Loop over the remaining tokens
while(st.hasMoreTokens()) {
String token = st.nextToken();
// As long a there are other tokens, you're processing the name
if(st.hasMoreTokens()) {
if(name.length() > 0) {
name = name + " ";
}
name = name + token;
}
// If there are no more tokens, you've reached the phone number
else {
phone = token;
}
}
System.out.println(id);
System.out.println(name);
System.out.println(phone);

optimising the search time in hashmap

I have a csv file which is hashmapped, whenever the user enter the city name(key) it will display all the details of that city. I have to optimize the search result time, everytime the it is reading the file(instead of only once) and displaying the values.
The CSV files contains data like this :
city,city_ascii,lat,lng,country,iso2,iso3,admin_name,capital,population,id
Malishevë,Malisheve,42.4822,20.7458,Kosovo,XK,XKS,Malishevë,admin,,1901597212
Prizren,Prizren,42.2139,20.7397,Kosovo,XK,XKS,Prizren,admin,,1901360309
Zubin Potok,Zubin Potok,42.9144,20.6897,Kosovo,XK,XKS,Zubin
Potok,admin,,1901608808
import java.io.File;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Scanner;
import java.io.IOException;
public class CSVFileReaders{
public static void main(String[] args) {
String filePath = "C:\\worldcities1.csv";
Scanner in = new Scanner(System.in);
System.out.println(" \n Enter the City name to be Searched : \n _> ");
long start = System.currentTimeMillis();
String searchTerm = in.nextLine();
readAndFindRecordFromCSV(filePath, searchTerm);
long end = System.currentTimeMillis();
System.out.println(" \n It took " + (end - start) + " Milli Seconds to search the result \n");
in.close();
}
public static void readAndFindRecordFromCSV( String filePath, String searchTerm) {
try{
HashMap<String,ArrayList<String>> cityMap = new HashMap<String,ArrayList<String>>();
Scanner x = new Scanner (new File(filePath),"UTF-8");
String city= "";
while(x.hasNextLine()) {
ArrayList<String> values = new ArrayList<String>();
String name = x.nextLine();
//break each line of the csv file to its elements
String[] line = name.split(",");
city = line[1];
for(int i=0;i<line.length;i++){
values.add(line[i]);
}
cityMap.put(city,values);
}
x.close();
//Search the city
if(cityMap.containsKey(searchTerm)) {
System.out.println("City name is : "+searchTerm+"\nCity details are accordingly in the order :"
+ "\n[city , city_ascii , lat , lng , country , iso2 , iso3 , admin_name , capital , population , id] \n"
+cityMap.get(searchTerm)+"");
}
else {
System.out.println("Enter the correct City name");
}
}
catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}`
the time should be optimized and every time i search it is reading the entire file(which should happen)

Currently you mix the map initialization inside the search function.
You don't want that.
First, init the map, then use it in the search function.
To do that, extract a method for statements that instantiate and value the map and then refactor the readAndFindRecordFromCSV() method so that it accepts a Map as additional parameter :
public static void readAndFindRecordFromCSV( String filePath, String searchTerm, HashMap<String,ArrayList<String>> dataByCity) {...}
With refactoring IDE features, it should be simple enough : "extracting method" then "change signature".
Here is a code (not tested at runtime but tested at compile time) that splits the logical in separated tasks and also rely on instance methods :
public class CSVFileReaders {
private final String csvFile;
private HashMap<String, ArrayList<String>> cityMap;
private final Scanner in = new Scanner(System.in);
public static void main(String[] args) {
String filePath = "C:\\worldcities1.csv";
CSVFileReaders csvFileReaders = new CSVFileReaders(filePath);
csvFileReaders.createCitiesMap();
csvFileReaders.processUserFindRequest(); // First search
csvFileReaders.processUserFindRequest(); // Second search
}
public CSVFileReaders(String csvFile) {
this.csvFile = csvFile;
}
public void createCitiesMap() {
cityMap = new HashMap<>();
try (Scanner x = new Scanner(new File(csvFile), "UTF-8")) {
String city = "";
while (x.hasNextLine()) {
ArrayList<String> values = new ArrayList<String>();
String name = x.nextLine();
//break each line of the csv file to its elements
String[] line = name.split(",");
city = line[1];
for (int i = 0; i < line.length; i++) {
values.add(line[i]);
}
cityMap.put(city, values);
}
x.close();
} catch (FileNotFoundException e) {
throw new RuntimeException(e);
}
}
public void processUserFindRequest() {
System.out.println(" \n Enter the City name to be Searched : \n _> ");
long start = System.currentTimeMillis();
String searchTerm = in.nextLine();
long end = System.currentTimeMillis();
System.out.println(" \n It took " + (end - start) + " Milli Seconds to search the result \n");
//Search the city
if (cityMap.containsKey(searchTerm)) {
System.out.println("City name is : " + searchTerm + "\nCity details are accordingly in the order :"
+ "\n[city , city_ascii , lat , lng , country , iso2 , iso3 , admin_name , capital , population , id] \n"
+ cityMap.get(searchTerm) + "");
} else {
System.out.println("Enter the correct City name");
}
}
}
The interesting part is here :
String filePath = "C:\\worldcities1.csv";
CSVFileReaders csvFileReaders = new CSVFileReaders(filePath);
csvFileReaders.createCitiesMap();
csvFileReaders.processUserFindRequest(); // First search
csvFileReaders.processUserFindRequest(); // Second search
The logical is clearer now.

Why do you create / load the CSV into a HashMap with every search ?
Just create the HashMap only once in the beginning, and then on every search just check whether it exists in the HashMap, eg move the read part into a separate method :
HashMap<String,ArrayList<String>> cityMap = new HashMap<String,ArrayList<String>>();
public static void readCSVIntoHashMap( String filePath) {
try{
Scanner x = new Scanner (new File(filePath),"UTF-8");
String city= "";
while(x.hasNextLine()) {
ArrayList<String> values = new ArrayList<String>();
String name = x.nextLine();
//break each line of the csv file to its elements
String[] line = name.split(",");
city = line[1];
for(int i=0;i<line.length;i++){
values.add(line[i]);
}
cityMap.put(city,values);
}
x.close();
...
}
Then have a separate method for searching :
public static void search(String searchTerm) {
if(cityMap.containsKey(searchTerm)) {
...
}
}

Creating an ArrayList from data in a text file

I am trying to write a program that uses two classes to find the total $ amount from a text file of retail transactions. The first class must read the file, and the second class must perform the calculations. The problem I am having is that in the first class, the ArrayList only seems to get the price of the last item in the file. Here is the input (which is in a text file):
$69.99 3 Shoes
$79.99 1 Pants
$17.99 1 Belt
And here is my first class:
class ReadInputFile {
static ArrayList<Double> priceArray = new ArrayList<>();
static ArrayList<Double> quantityArray = new ArrayList<>();
static String priceSubstring = new String();
static String quantitySubstring = new String();
public void gatherData () {
String s = "C:\\filepath";
try {
FileReader inputFile = new FileReader(s);
BufferedReader bufferReader = new BufferedReader(inputFile);
String line;
String substring = " ";
while ((line = bufferReader.readLine()) != null)
substring = line.substring(1, line.lastIndexOf(" ") + 1);
priceSubstring = substring.substring(0,substring.indexOf(" "));
quantitySubstring = substring.substring(substring.indexOf(" ") + 1 , substring.lastIndexOf(" ") );
double price = Double.parseDouble(priceSubstring);
double quantity = Double.parseDouble(quantitySubstring);
priceArray.add(price);
quantityArray.add(quantity);
System.out.println(priceArray);
} catch (IOException e) {
e.printStackTrace();
}
}
The output and value of priceArray is [17.99], but the desired output is [69.99,79.99,17.99].
Not sure where the problem is, but thanks in advance for any help!

Basically what you have is:
while ((line = bufferReader.readLine()) != null) {
substring = line.substring(1, line.lastIndexOf(" ") + 1);
}
priceSubstring = substring.substring(0,substring.indexOf(" "));
quantitySubstring = substring.substring(substring.indexOf(" ") + 1 , substring.lastIndexOf(" ") );
double price = Double.parseDouble(priceSubstring);
double quantity = Double.parseDouble(quantitySubstring);
priceArray.add(price);
quantityArray.add(quantity);
System.out.println(priceArray);
So all you are doing is creating a substring of the line you just read, then reading the next line, so basically, only the substring of the last will get processed by the remaining code.
Wrap the code in {...} which you want to be executed on each iteration of the loop
For example...
while ((line = bufferReader.readLine()) != null) {
substring = line.substring(1, line.lastIndexOf(" ") + 1);
priceSubstring = substring.substring(0,substring.indexOf(" "));
quantitySubstring = substring.substring(substring.indexOf(" ") + 1 , substring.lastIndexOf(" ") );
double price = Double.parseDouble(priceSubstring);
double quantity = Double.parseDouble(quantitySubstring);
priceArray.add(price);
quantityArray.add(quantity);
System.out.println(priceArray);
}
This will execute all the code within the {...} block for each line of the file

array in array list

In the input file, there are 2 columns: 1) stem, 2) affixes. In my coding, i recognise each of the columns as tokens i.e. tokens[1] and tokens[2]. However, for tokens[2] the contents are: ng ny nge
stem affixes
---- -------
nyak ng ny nge
my problem here, how can I declare the contents under tokens[2]? Below are my the snippet of the coding:
try {
FileInputStream fstream2 = new FileInputStream(file2);
DataInputStream in2 = new DataInputStream(fstream2);
BufferedReader br2 = new BufferedReader(new InputStreamReader(in2));
String str2 = "";
String affixes = " ";
while ((str2 = br2.readLine()) != null) {
System.out.println("Original:" + str2);
tokens = str2.split("\\s");
if (tokens.length < 4) {
continue;
}
String stem = tokens[1];
System.out.println("stem is: " + stem);
// here is my point
affixes = tokens[3].split(" ");
for (int x=0; x < tokens.length; x++)
System.out.println("affix is: " + affixes);
}
in2.close();
} catch (Exception e) {
System.err.println(e);
} //end of try2

You are using tokens as an array (tokens[1]) and assigning the value of a String.split(" ") to it. So it makes things clear that the type of tokens is a String[] array.
Next,
you are trying to set the value for affixes after splitting tokens[3], we know that tokens[3] is of type String so calling the split function on that string will yield another String[] array.
so the following is wrong because you are creating a String whereas you need String[]
String affixes = " ";
so the correct type should go like this:
String[] affixes = null;
then you can go ahead and assign it an array.
affixes = tokens[3].split(" ");

Are you looking for something like this?
public static void main(String[] args) {
String line = "nyak ng ny nge";
MyObject object = new MyObject(line);
System.out.println("Stem: " + object.stem);
System.out.println("Affixes: ");
for (String affix : object.affixes) {
System.out.println(" " + affix);
}
}
static class MyObject {
public final String stem;
public final String[] affixes;
public MyObject(String line) {
String[] stemSplit = line.split(" +", 2);
stem = stemSplit[0];
affixes = stemSplit[1].split(" +");
}
}
Output:
Stem: nyak
Affixes:
ng
ny
nge