I'm trying to write a method to take a multiline tab-delimited file and return the contents of that file as an arraylist of String arrays (each line is a String[], and each such String[] is an element of an arraylist). My problem is, I can't tell if the output is correct or not. I've printed each arraylist element and String[] element as they are saved to the arraylist, and those printings look correct. But after the arraylist is returned and I print the String[] in it, they appear to only have the contents of the very last line of the file. I'm suspecting it might be something about FileReader or BufferedReader that I don't know. Anyhoo, here's the code:
public class DataParsingTest {
static File AAPLDailyFile = new File("./textFilesForMethodTests/dataParsingPractice2.tsv");
public static void main(String[] args) throws FileNotFoundException, IOException {
ArrayList<String[]> stringArrayList = fileToStringArray(AAPLDailyFile);
System.out.println("stringArray.size() = " + stringArrayList.size());
System.out.println(stringArrayList.get(0)[0]);
for (int i = 0; i < stringArrayList.size(); i++) {
for (int j = 0; j < stringArrayList.get(i).length; j++) {
System.out.println("index of arraylist is " + i + " and element at index " + j + " of that array is " + stringArrayList.get(i)[j]);
}
}
}
public static ArrayList<String[]> fileToStringArray(File file) throws FileNotFoundException, IOException {
ArrayList<String[]> arrayListOfStringArrays = new ArrayList<String[]>();
FileReader fileReader = new FileReader(file);
BufferedReader bufferedReader = new BufferedReader(fileReader);
int nextChar = 0;
int noOfTokens = 1; // because the first token doesn't have a tab or newline before it
int startIndex = 0, endIndex = 0, tokenIndex = 0;
String toRead = "";
toRead = bufferedReader.readLine();
for (int i = 0; i < toRead.length(); i++) {
if (toRead.charAt(i) == '\t') {
noOfTokens++;
}
}
System.out.println("noOfTokens = " + noOfTokens);
bufferedReader.close();
fileReader.close();
String[] productString = new String[noOfTokens];
startIndex = 0;
endIndex = 0;
tokenIndex = 0;
FileReader fileReader2 = new FileReader(file);
BufferedReader bufferedReader2 = new BufferedReader(fileReader2);
tokenIndex = 0;
int count = 1;
while ((toRead = bufferedReader2.readLine()) != null) {
System.out.println("toRead = " + toRead);
startIndex = -1; // [L - so that the first time an array element is assigned, it's upped to 0]
endIndex = 0;
tokenIndex = 0;
while (true) {
endIndex = toRead.indexOf("\t", startIndex + 1);
if (endIndex == -1) {
productString[tokenIndex] = toRead.substring(startIndex + 1);
System.out.println("tokenIndex = " + tokenIndex);
System.out.println("productString[" + tokenIndex + "] = " + productString[tokenIndex]);
tokenIndex++;
count++;
arrayListOfStringArrays.add(productString);
System.out.println("just added an array to the list. the first element is " + productString[0]);
break;
}
productString[tokenIndex] = toRead.substring(startIndex + 1, endIndex);
System.out.println("tokenIndex = " + tokenIndex);
System.out.println("productString[" + tokenIndex + "] = " + productString[tokenIndex]);
startIndex = endIndex;
tokenIndex++;
count++;
}
}
fileReader2.close();
bufferedReader2.close();
return arrayListOfStringArrays;
}
}
The input file is:
1 2
3 4
5 6
The output is:
noOfTokens = 2
toRead = 1 2
tokenIndex = 0
productString[0] = 1
tokenIndex = 1
productString[1] = 2
just added an array to the list. the first element is 1
toRead = 3 4
tokenIndex = 0
productString[0] = 3
tokenIndex = 1
productString[1] = 4
just added an array to the list. the first element is 3
toRead = 5 6
tokenIndex = 0
productString[0] = 5
tokenIndex = 1
productString[1] = 6
just added an array to the list. the first element is 5
stringArray.size() = 3
5 // from here on up, it looks like the method works correctly
index of arraylist is 0 and element at index 0 of that array is 5
index of arraylist is 0 and element at index 1 of that array is 6
index of arraylist is 1 and element at index 0 of that array is 5
index of arraylist is 1 and element at index 1 of that array is 6
index of arraylist is 2 and element at index 0 of that array is 5
index of arraylist is 2 and element at index 1 of that array is 6 //these 6 lines only reflect the last line of the input file.
Thanks a mil!