Thread: Having difficulty with ArrayList method ".contains", any feedback greatly appreciated!

Hello, the objective of my program is to read a file called input_data.txt and to calculate an invoice in which my program will print the results in a formatted text file. I haven't advanced to this step yet because I'm having trouble checking my ArrayList for a certain string. The reason I am searching for "duration" is so that my program will know when the heading is complete.

Here is the sample input file given:
account_number start_time_of_call duration
10011A 21:50 20.2
10011A 13:23 12.3
10033C 23:00 34.0
00101B 10:23 45.1

Eventually, I must separate the fields and calculate payment prices based on the duration and time of the calls.
Any suggestions are much appreciated, even conceptual or logical suggestions because I feel I am not going in the right direction.

Thank you

import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
 
public class spInputOutput {
 
	public static PrintWriter outputStream;
 
	public static void main(String[] args) throws IOException
	{
		readData();
	}
 
	public static void readData() throws IOException
	{
		double monthlyBase = 20;
		double amountDue = 0;
		double time = 0.00;
 
		ArrayList<String> fileCont = new ArrayList<String>();
 
		double daytimeCall = 0.12;  /*per minute for calls that started between 8:00 AM and 10:00PM, 
		inclusive $0.05 per minute all other times*/
 
		/*
		{
			System.out.println("Account");
			System.out.println(monthlyBase);
			System.out.println(time);
			System.out.println(daytimeCall);
		}*/		
 
		FileReader fr = new FileReader("input_data.txt");
		BufferedReader br = new BufferedReader(fr);
 
		String invoice = "invoice.txt";
        try {
			outputStream = new PrintWriter(invoice);
		}
        catch (FileNotFoundException e) {
			e.printStackTrace();
		}
 
        outputStream.println("Invoice");
        outputStream.println("**********");
        outputStream.println("");
        outputStream.println("Account");	
        outputStream.println("Amount Due");
 
        outputStream.close();
 
		String text = "";
		String line = br.readLine();
		String searchString = "duration";
 
		while(line != null)
		{
			text += line;
			line = br.readLine();
			fileCont.add(line);
 
			//THIS IS WHERE MY PROBLEM IS
                        boolean check = fileCont.contains(searchString);
 
		      if (check == true) 
		      {
		    	  System.out.println("duration found");
		      }
		      else
			  {
				System.out.println("duration not found");
			  }
 
		//System.out.println(text);	
		}
 
		System.out.println("Inovice");
 
	}
}

Can't you read each line as a String and break them into 3 parts split on the spaces, always knowing the last item is the 'duration?' Something like

// read each line into a String[] array split on the spaces
String[] inputLine = br.readLine().split( " " );

If you are committed to using an arraylist for this task, you may want to print out each object to see if it contains what you expect. If an arraylist is optional, GregBrannon's method would work very nicely.

Hello,

Using an ArrayList is not mandatory so I will use GregBannon's suggestion. Will the array work if the file length varies (if I have a text file with 20 account numbers)?

I used an ArrayList initially because I know arrays have determined lengths.

The method that GregBrannon showed would work with any length as the array is only intended to hold one set of data (one line) at a time, not the entire file's text. So, you split the line into the 3 parts then do something with it, perhaps print it out or w/e you want really, and on the next iteration the values in the array would change to the next line; repeat process until the end of file.

Hello KucerakJM,

I have attempted to implement the array solution and was able to gather the data in a (String) line of text. My problem is that I don't know how to use substring or split to obtain elements in that line of data. I need to retrieve the account number and total amounts (which will be calculated) in arraylists because these values (customers and total amount of total orders) is subject to change. Here is my updated code, no errors.

import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
 
public class spInputOutput {
 
	public static PrintWriter outputStream;
 
	public static void main(String[] args) throws IOException
	{
		readData();
	}
 
	public static void readData() throws IOException
	{
		double monthlyBase = 20;
		double amountDue = 0;
		double time = 0.00;
 
		ArrayList<Double> amtDue = new ArrayList<Double>();
		ArrayList<String> accts = new ArrayList<String>();
		ArrayList<String> fileCont = new ArrayList<String>();
 
		double daytimeCall = 0.12;  /*per minute for calls that started between 8:00 AM and 10:00PM, 
		inclusive $0.05 per minute all other times*/
 
		FileReader fr = new FileReader("input_data.txt");
		BufferedReader br = new BufferedReader(fr);
 
		String invoice = "invoice.txt";
        try {
			outputStream = new PrintWriter(invoice);
		}
        catch (FileNotFoundException e) {
			e.printStackTrace();
		}
 
        outputStream.println("Invoice");
        outputStream.println("**********");
        outputStream.println("");
        outputStream.println("Account");
        for(int i=0; i<5; i++)
        {
        	outputStream.println(accts);
        }
        outputStream.println("Amount Due");
        for(int i=0; i<5; i++)
        {
        	outputStream.println("20.20\n");
        }
        outputStream.println("**********");
        outputStream.println("Total");
 
 
        outputStream.close();
 
		String text = "";
		String line = br.readLine();
		String[] a = new String[10];
 
                //The values for this for loop were used to see if my program would still run
 
		for(int i = 0; i<a.length ; i++)
		{
			a[i] = br.readLine();
			//a[i].split("");
 
		}
		System.out.println(a[1]);
		System.out.println(a[2]);
 
 
		while(line != null)
		{
			text += line;
			line = br.readLine();
			fileCont.add(line);
		//System.out.println(text);	
		}
 
		System.out.println("Invoice File Created");
 
	}
}

My objectives are currently to;

1. Format the input document so that the account numbers can be obtained and re-presented in the output file
2. Calculate the total amount with the start time and duration considered (I still must derive this algorithm)
3. Print these values to the invoice file

Thanks again for your help so far