Passing Jave object arrays

[Alexander Berry]

Hello,

I have a little bit of code here and what it is attempting to do is read a file into a arraylist then return the array object to another method/Class for testing I am just using a method later it will e a class.

I can get the createObj code to work and but I have loss may way attempting to figure out how to get the readObj method to take the class and use the array.

The code is below any help would be greatly appreciated.

Thanks,

Alex.

 public class filetoobject {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        // new filetoobject().createObj();
        filetoobject fo = new filetoobject();
        fo.createObj();
        fo.ReadOjb(Object o);
    }
 void ReadOjb(Object o) {
        
    //    System.out.println("Number of Elements in the list passed: " + o.Lentgh());
    }

    Object createObj() {

        ArrayList<String> list = new ArrayList<String>();

        // TODO code application logic here
        //
        // Create an instance of File for data.txt file.
        //
        File file = new File("C:\\sysiclog.txt");

        try {
            //
            // Create a new Scanner object which will read the data from the
            // file passed in. To check if there are more line to read from it
            // we check by calling the scanner.hasNextLine() method. We then
            // read line one by one till all line is read.
            //
            Scanner scanner = new Scanner(file);
            while (scanner.hasNextLine()) {
                String line = scanner.nextLine();
                list.add(line);
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
        System.out.println("Number of Elements in the list: " + list.size());
        return list;

    }
   
}



   

[David Newton]

Your method that reads should return a list, and the other method should take one. A list is an object, but an object isn't (necessarily) a list.

[Alexander Berry]

I can't seem to get the arraylist method signature correct in readObj and I am not sure I have it correct in the return.

This is what I have so far:

  public class filetoobject {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        // new filetoobject().createObj();
        filetoobject fo = new filetoobject();
        fo.createObj();
        fo.ReadOjb((ArrayList<String>) list); //this doesn't work
    }
 void ReadOjb(ArrayList<String> list) {

    //    System.out.println("Number of Elements in the list passed: " + o.Lentgh());
    }

     ArrayList<String> createObj() {// should this contain the list value if so it doesn't work

        ArrayList<String> list = new ArrayList<String>();

        // TODO code application logic here
        //
        // Create an instance of File for data.txt file.
        //
        File file = new File("C:\\sysiclog.txt");

        try {
            //
            // Create a new Scanner object which will read the data from the
            // file passed in. To check if there are more line to read from it
            // we check by calling the scanner.hasNextLine() method. We then
            // read line one by one till all line is read.
            //
            Scanner scanner = new Scanner(file);
            while (scanner.hasNextLine()) {
                String line = scanner.nextLine();
                list.add(line);
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
        System.out.println("Number of Elements in the list: " + list.size());
        return (ArrayList<String>) list ; // not sure if this is correct looks like I am type casting

    }
   
}


  

[Alexander Berry]

I have it working between the two method now.

OK, OK, OK, I forgot the basics.

My next task is to get it working between classes via return. Until then I will consider this close I will repost if I have a problem.

Thanks for your help: Below is the code.

  public class filetoobject {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        new filetoobject().createObj();

    }

    void createObj() {

        ArrayList<String> list = new ArrayList<String>();

        // TODO code application logic here
        //
        // Create an instance of File for data.txt file.
        //
        File file = new File("C:\\sysiclog.txt");

        try {
            //
            // Create a new Scanner object which will read the data from the
            // file passed in. To check if there are more line to read from it
            // we check by calling the scanner.hasNextLine() method. We then
            // read line one by one till all line is read.
            //
            Scanner scanner = new Scanner(file);
            while (scanner.hasNextLine()) {
                String line = scanner.nextLine();
                list.add(line);
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
        System.out.println("Number of Elements in the list: " + list.size());
        ReadObj(list);

    }

    void ReadObj(ArrayList<String> list) {

        System.out.println("Number of Elements in the list passed: " + list.size());
    }
}