This is my 3rd solution, Not passing the validation test

Question about the task

Prices

Java Core, Level 8, Lesson 11

Under discussion

It works on my machine though

CrUD for a table inside a file.
Read a file name for CrUD operations from the console.

The program is started with the following arguments:
-c productName price quantity

Argument values:
where id is 8 characters.
productName is 30 characters.
price is 8 characters.
quantity is 4 characters.
-c adds the product with the specified parameters to the end of the file, and generates an id by incrementing the maximum id found in the file.

The file data is stored in the following order (without separating spaces):
id productName price quantity

Each data field is padded with spaces up to its length.

Before adding a new line, re-write all of its contents to the file.

Example:
19847 Swim trunks, blue 159.00 12 198479 Swim trunks, black with printe173.00 17 19847983Snowboard jacket with reflecti10173.991234

Requirements:

The program should read a file name for CrUD operations from the console.
The Solution class should not use static variables.
When you run the program without arguments, the product list must remain unchanged.
When the program is run with the arguments "-c productName price quantity", a new line with the corresponding product should be added to the end of the file.
The product must have the next id after the maximum id found in the file.
The format of the new product line must precisely match that format specified in the task.
The file streams must be closed.

package com.codegym.task.task18.task1827; /* Prices */ import java.io.*; import java.util.ArrayList; public class Solution { public static void main(String[] args) throws Exception { BufferedReader reader = new BufferedReader(new InputStreamReader(System.in)); String fileName = reader.readLine(); reader.close(); //make an arraylist of arraylists to store all arguments from every line in a separate location ArrayList<ArrayList<String>> fileData = fileBreakDown(fileName); if (args.length > 0 && args[0].equals("-c")){ String[] arguments = new String[]{args[1],args[2],args[3]}; addToList(fileData, arguments); } //write all data back to the file try { FileWriter out = new FileWriter(fileName); for (ArrayList<String> oneLine : fileData){ out.write(String.format("%-8s", oneLine.get(0))); out.write(String.format("%-30s", oneLine.get(1))); out.write(String.format("%-8s", oneLine.get(2))); out.write(String.format("%-4s", oneLine.get(3))); out.write("\r\n"); } out.close(); } catch (IOException e) {} } private static ArrayList<ArrayList<String>> fileBreakDown(String fileName){ String st; ArrayList<ArrayList<String>> fileData = new ArrayList<>(); BufferedReader br; try { br = new BufferedReader(new FileReader(new File(fileName))); //retrieve data from each stored line in the file and add them to the arraylist while ((st = br.readLine()) != null){ ArrayList<String> lineData = new ArrayList<>(); lineData.add(st.substring(0, 8).trim()); //8 possible characters, no place-holders lineData.add(st.substring(8, 38).trim()); //30 possible characters, no place-holders lineData.add(st.substring(38,46).trim()); //8 possible characters, no place-holders lineData.add(st.substring(46).trim()); //4 possible characters, no place-holders fileData.add(lineData); } br.close(); } catch (IOException e) {} return fileData; } private static void addToList(ArrayList<ArrayList<String>> fileData, String[] newEntryArray){ //find the proper id number for the new line of data String lastStrId; int lastIntID; int nextID = 0; for (int i = 0; i < fileData.size(); i++){ lastStrId = fileData.get(i).get(0); lastIntID = Integer.parseInt(lastStrId.trim()); if (lastIntID > nextID){ nextID = lastIntID; } } //add the new line derived from args to the arraylist made of all file data ArrayList<String> newLine = new ArrayList<>(); newLine.add(Integer.toString(nextID+1)); newLine.add(newEntryArray[0]); newLine.add(newEntryArray[1]); newLine.add(newEntryArray[2]); fileData.add(newLine); } }

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Guadalupe Gagnon

Level 37 , Tampa, United States

8 October 2019, 14:49

I think that you may be over thinking this task a bit: Try doing it like this: - read the initial data in first, parsing into an int the first 8 characters and setting that to max, and replacing the value of max when a new max value is found - using the max value, add one, then format the data in arguements and add it to the end of the list - output list Here is some psuedocode: ArrayList<String> data; int max = min_value; FileReader = Reader with file name; loop (read data until all data is read){ data.add(readline()) int temp = Parserint(data.get(i).substring(0,8)) if temp > max set max to temp; } create a new string like this: String = ("%-8s", (max+1)) + ("%-30s",args[1]) etc..... add that string to data then output data

Hossein Shams

Level 26 , Atlanta, United States

8 October 2019, 23:01

Thank you for following my problems. Do you see any bug in my code? The way you described the solution, I guess there should be something with generating the next ID. Am I right?

Guadalupe Gagnon

Level 37 , Tampa, United States

8 October 2019, 23:38

try changing line 31 to remove the carriage return to:

out.write("\n");

Hossein Shams

Level 26 , Atlanta, United States

9 October 2019, 00:01

Didn't help. Thank you though. I think CodeGym's validation system is not flexible about the algorithm in most cases. I'll get back to this problem another time.

Guadalupe Gagnon

Level 37 , Tampa, United States

9 October 2019, 00:05

definitely not flexible. I have found that the longer the code the more chances of some failure on the verification.