Using BufferedReader

[CaptRage61]

How do you use Buffered reader to read from a file. I have a class set up with a few variables. And I have a file where every line would be a new instance of this class and there are 5 things in each line seperated by tabs. Each thing on each line would be stored in the different variables. How do I do this;

Ex:
class file
variable a, b, c, d, e;

data file:
part1 part2 part3 part4 part5

need to set a=part1; b=part2 ......

 

[Bones3]

To parse the line from your data file, check out StringTokenizer class in java.util.* . Set \t as the delimiter. (You might want to set " " (white space) as a delimiter too.)

Make a buffered reader for each file.

BufferedReader fileIn = new BufferedReader(new FileReader("File_Name"));

Here is some more example code:

http://www.cs.fit.edu/~wallen/cse1002/notes/CSE1002_Example15c.html

-Bones

 

[CaptRage61]

I got it set up where it I can grab each peice of data from each line. How do I then take that and create a new Element object ( I already have the class created )
Here is my Element Class:

public class Element {
    String name;
    String symbol;
    int number;
    double weight, bp;


    public Element() {
    }
    public Element(String n, String s, int num, double w, double b){
        name = n;
        symbol = s;
        number = num;
        weight = w;
        bp = b;
    }
    public String getName(){
        return name;
    }
    public String getSymbol(){
        return symbol;
    }
    public int getNumber(){
        return number;
    }
    public double getWeight(){
        return weight;
    }
    public double getBP(){
        return bp;
    }
    
}

here is where I am reading from the file, the comments are where I am stuck

public void readFile(File inFile) {
        try {
            StringTokenizer tokenizedString;
            BufferedReader inStream = null;
            int lineNum = 0;
            int tokenCount = 0;
            int elementNumber = 0;
            Object[] element = new String[5];
            String inputLine = null;
            String tokenDelimiters = " \t ";
            inStream = new BufferedReader(new FileReader(inFile));
            do {
                inputLine = inStream.readLine();
                if (inputLine != null && inputLine.length() > 0) {
                    lineNum++;
                    tokenizedString = new StringTokenizer(inputLine,
                            tokenDelimiters);
                    String token = null;
                    while(tokenizedString.hasMoreTokens())   {
                        token = tokenizedString.nextToken();
               //Create a new element
                if(token != null)  {
                   //add each token to the element
                  tokenCount++;
              }
              //add each element to the table
            }

                }
            } while (inputLine != null);

        } catch (IOException e) {
        }
    }

Anyone know how to get this to work?

 

[obadare]

tokenizedString = new StringTokenizer(inputLine,
tokenDelimiters);
while(tokenizedString.hasMoreElement()){
String n =tokenizedString.nextToken();
String s =tokenizedString.nextToken();
int num =Integer.parseInt(tokenizedString.nextToken());
double w =Double.parseDouble(tokenizedString.nextToken());
double b =Double.parseDouble(tokenizedString.nextToken());

Element e=new Element(n,s,num,w,b);
// and do whatever you want to your element.
}

 

[CaptRage61]

Thanks that worked, I did figure out how to do it but my way was really messy.

Now say that there is X lines that I need to read from the file and I need to create X Elements. How would I write a loop that would create all of these? What I was thinking was haveing a counter and name each Element e1, e2, e3, eX. How do I name this? I tried:

int counter = 1;
Element e + counter = new element(n,s,num,w,b);
counter++;

But this don't work it does not like the e+ counter

 

[Diancecht]

You can't define variable names at runtime.

I'd store it in an ArrayList.

For each new Element you create, do an ArrayList.add().

Cheers,

Dian

 

[CaptRage61]

would I do:

Element e1=new Element(n,s,nu,,w,b);
ArrayList al = new ArrayList();
al.add(counter,e1);
counter++;

Would this work?

 

[CaptRage61]

That did work and I have the ArrayList created and it contains all of my Elements.

I need to create a loop to get these into an Object array.

how do I get the array list to return my Element so I can call the getName and other methods.

Here is what I tried:

int x = al.size();
for(int y=0; y<= x; y++){
Element w = new Element();
w = al.get; <================ Incompatable types found
}

The goal is to get and Object array creates with all the data.
Ex:
Object [][] data = { { e1.getName(), e1.getSymbol().....}
{e2.getName(), e2.getSymbol()..............}
{all other elements......} }

I need this object array so I can pass it into a JTable.

 

[Diancecht]

Well, you can just add the Elements to the ArrayList without the counter, ArryList will do it for you.

And to recover them in an array try

Element[] runtimeType = new Element[];
Element[] myElements = myArrayList.toArray(runtimeType);

Take a look at ArrayList API if you don't understand it.

Cheers,

Dian

 

[CaptRage61]

That is not exactly what I want. I already have all of my Elements in an ArrayList, now what I need to do is place all of the information from each and all elements into and 2D Object array : Object[][] so I can pass that array as the data into a JTable.

 

[Diancecht]

Then iterate through the ArrayList, and fill the new array with the values got from the Elements.

Cheers,

Dian