Java passing value from array to new object instance

Question

I have some issues with the passing array values to the constructor. I have a file.txt which contains some lines with values, for example:

peter|berlin|germany|0930295235|foo.

I figured out how to transform the lines into the arrays. But I don't know how to pass the values from arrays to the constructor to transform the arrays into the objects with the array attributes.

Here is the main class:

import java.io.BufferedReader;
import java.io.DataInputStream;
import java.io.FileInputStream;
import java.io.InputStreamReader;


public class FileReader {

    public static void main(String[] args) {
        try {
            // Open the file that is the first 
            // command line parameter
            FileInputStream fstream = new FileInputStream("file.txt");
            // Get the object of DataInputStream
            DataInputStream in = new DataInputStream(fstream);
            BufferedReader br = new BufferedReader(new InputStreamReader(in));
            String strLine;

            // Read the file line by line
            while ((strLine = br.readLine()) != null) {
                // Print the content on the console
                String s[] = strLine.split("\\|");
                // System.out.println(java.util.Arrays.toString(s));
                // System.out.println (strLine);
                for (String element : s) {
                    System.out.println(element);
                    // HERE I NEED TO PASS THE ARRAY VALUES FOR EACH LINE TO TRANSFORM THE ARRAYS TO OBJECTS
                    Item item = new Item(element,element,element,element,element);
                    System.out.println("*************************************");
                }
                // Close the input stream
                in.close();
            } catch (Exception e) { //Catch exception if any
                System.err.println("Error: " + e.getMessage());
        }
    }
}

Here is the class Item:

public class Item {

    private String name;
    private String city;
    private String state;
    private String number;
    private String foo;

    public Object(String name, String city, String state, String number,String foo){
        this.name = name;
        this.city = city;
        this.state = state;
        this.number = number;
        this.foo = foo; 
    }

    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getCity() {
        return city;
    }
    public void setCity(String city) {
        this.city = city;
    }
    public String getState() {
        return state;
    }
    public void setState(String state) {
        this.state = state;
    }
    public String getNumber() {
        return number;
    }
    public void setNumber(String number) {
        this.number = number;
    }
    public String getFoo() {
        return foo;
    }
    public void setFoo(String foo) {
        this.foo = foo;
    }
}

I need objects for more work with the data. I appreciate any help.

Choose a better name for your class that describes what it is for, don't confuse it with the one that already exist — codingbiz
– codingbiz, Commented Nov 23, 2012 at 11:51
You should not be calling your class Object - that's a Java superclass — cud_programmer
– cud_programmer, Commented Nov 23, 2012 at 11:51

Edd · Accepted Answer · 2012-11-23 12:02:54Z

2

I think what you want to do is something like the following, although it's not entirely clear.

String s[] = strLine.split("\\|");
Item item = new Item(s[0], s[1], s[2], s[3], s[4]);

Also note that after you've created your new Item object it will fall out of scope nearly immediately, so you need to store it in some sort of container declared outside of your while loop:

List<Item> items = new ArrayList<Item>();
String line;

while((line = br.readLine()) != null) {
    String[] words = line.split("\\|");
    Item item = new Item(words[0], words[1], words[2], words[3], words[4]);
    items.add(item);
}

edited Nov 23, 2012 at 12:02

answered Nov 23, 2012 at 11:55

Edd

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Comments

The Cat · Accepted Answer · 2012-11-23 11:54:28Z

1

I dont think you need this for loop.

for(String element : s)
{
}

If you are looking to extract particular Strings from the array you should use something like,

String name = s[0];

but be careful not to select items outside the range of the array.

answered Nov 23, 2012 at 11:54

The Cat

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Comments

Evgeniy Dorofeev · Accepted Answer · 2012-11-23 11:56:55Z

1

String s[] = strLine.split("\\|");
Object item = new Object(s[0],s[1],s[2],s[3],s[4]);

answered Nov 23, 2012 at 11:56

Evgeniy Dorofeev

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Comments

MC Emperor · Accepted Answer · 2012-11-23 12:13:56Z

1

You shouldn't have a for loop there, just pass each array value to the Objects constructor, having first checked that you have the right number of values. The new Object is already used in Java, so call your class (rembember the difference between object and class), MyObj.

MyObj myObj = null; // De
String s[] = strLine.split("\\|");
if (s.length==5){
  myObj = new MyObj(s[0],s[1],s[2],s[3],s[4]);
} else {
  System.err.println("Wrong number of arguments on the line"+strLine);
}

It might be clearly to use a constructor with no parameters and then set each of fields with

myObj = new MyObj();
myObj.setName( s[0]); //etc

Which is slight more readable, as to which data goes into which field

edited Nov 23, 2012 at 12:13

MC Emperor

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answered Nov 23, 2012 at 11:58

Dr BDO Adams

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Comments

Aditya Jain · Accepted Answer · 2012-11-23 11:54:34Z

0

How about changing the for loop to:

for(int i=0;i<s.size();i+=5) {
      System.out.println(s[i]);
      Object item = new Object(s[i],s[i+1],s[i+2],s[i+3],s[i+4]);
 }

But this assumes size of 's' is of form 5n; n being 1,2,3...

answered Nov 23, 2012 at 11:54

Aditya Jain

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Comments

MC Emperor · Accepted Answer · 2012-11-23 12:02:14Z

0

Since you know the structure of file.txt, and thus the length of String[] s, you can call each element of the arrays you have:

for (String element : s) {
    System.out.println(element);
    Item item = new Item(s[0], s[1], s[2], s[3], s[4]);
}

In order to save the Item items and not overwrite them with the next element in the loop, you can save it to an array with your items (start with declaring an array):

public static void main(String[] args) {
    try {
        ArrayList<Item> items = new ArrayList<Item>();
        ...

and then

for (String element : s) {
    System.out.println(element);
    Item item = new Item(s[0], s[1], s[2], s[3], s[4]);
    items.add(item);
}

answered Nov 23, 2012 at 12:02

MC Emperor

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