Question

I have a text file with about 200 item numbers and descriptions, which is formatted like this (without the bullets):

• 1642 Pure wool t-shirt
• 613 Red laced shoes
• 3477 Blue hat with feather
• …

I am trying to read and store the items numbers and descriptions into respective arrays, which is delimited by space. My issues are:

1. I want to ignore the spaces in the description.
2. When I sort or delete items, I want to ensure that the description gets deleted as well.

Here’s what I have tried so far but getting ArrayIndexOutOfBoundsException error and I am not even sure if it will read the description properly:

private Scanner file;
private int item = 0;
private String desc = "";
private int[] itemArr = new int[200];
private String[] descArr = new String[200];
int n = 0;


public void openFile(){

    try{
        file = new Scanner(new File("inventory.txt"));
    }

    catch(Exception e){
        System.out.println("file not found");
    }

}

public void readFile(){         

    while(file.hasNextLine()){    
        if (file.hasNextInt()){     
            item = file.nextInt();
        }

        while(!file.hasNextInt() && !file.hasNextLine()){
            desc = desc + file.next() + " ";
        }

        itemArr[n] = item;
        descArr[n] = desc;
        n++;
    }

    for (int i = 0; i < n; i++){
        System.out.println(itemArr[i] + " " + descArr[n] + "\n");
    }
    System.out.println("Total Records (n): " + n);

}

Or is there a better way to do this? I’ve read some post about Patterns and Regex, but not sure how to use that either.

Thank you!

Answer 1

There is no protection on n exceeding 200. If there are more that 200 iterations of the while loop then:

itemArr[n] = item;

will throw an ArrayIndexOutOfBoundsException.

If the int at the beginning of each line is unique you could use a Map<Integer, String> to store the data. This will not place a limit of 200 on the number of items that can be read from the file and if you selected a TreeMap as the implementation it would sort them (you can either accept the natural ordering of Integer or define you own Comparator). As suggested by sethu you could use a BufferedReader to read the file.

For example:

BufferedReader br = new BufferedReader(new FileReader("inventory.txt"));
Map<Integer, String> items = new TreeMap<Integer, String>();

String line;
while (null != (line = br.readLine()))
{
    String[] line_parts = line.split(" ");
    if (line_parts.length > 1)
    {
        StringBuilder desc = new StringBuilder(line_parts[1]);
        for (int i = 2; i < line_parts.length; i++)
        {
            desc.append(line_parts[i]);
        }
        items.put(new Integer(line_parts[0]), desc.toString());
    }
}

for (Integer key: items.keySet())
{
    System.out.println(key + " = " + items.get(key));
}