Thread: Adding Object to ArrayList

import java.util.*;
import javax.swing.*;
public class Library 
{
	int id;
	String date;
	String description;
	int copies;
	String title;
	int bookCount;
	int magCount;
	int multiCount;
 
	ArrayList<Book> newBook = new ArrayList<Book>();
	ArrayList<Magazine> newMag = new ArrayList<Magazine>();
	ArrayList<Multimedia> newMulti = new ArrayList<Multimedia>();
	ArrayList<Library> newLib = new ArrayList<Library>();
 
	public void addItem(int newId, String newDate, String newDesc, int newCopies, String newTitle, String newAuthor, String newPub, int newIsbn)
	{
		for(int x = 0; x < newBook.size(); x++)
		{
			bookCount++;
 
                        // I'am having trouble here in adding book object to my arraylist.
			newBook.get(x) = new Book();
			newBook.get(x).setId(newId);
			newBook.get(x).setDate(newDate);
			newBook.get(x).setDescription(newDesc);
			newBook.get(x).setCopies(newCopies);
			newBook.get(x).setTitle(newTitle);
			newBook.get(x).setAuthor(newAuthor);
			newBook.get(x).setPublisher(newPub);
			newBook.get(x).setIsbn(newIsbn);
		}		
	}
 
        // and i think this method does not work because it cannot retrieve anything, because my addItem method isn't working
	public void retrieveItem(int id)
	{
		for(int x = 0; x < bookCount; x++)
		{
			if(id == newBook.get(x).getID())
			{
				JOptionPane.showMessageDialog(null, "Book Title: " + newBook.get(x).getTitle() + "\nBook Author: " + newBook.get(x).getAuthor() + 
				"\nBook Publisher: " + newBook.get(x).getPublisher() + "\nBook ID: " + newBook.get(x).getID() + 
				"\nBook ISBN: " + newBook.get(x).getIsbn() + "\nDate Acquired: " + newBook.get(x).getDate()
    		    + "\nNumber of Copies: " + newBook.get(x).getCopies() + "\nDescription: " + newBook.get(x).getDescription());
			}
 
			else
			{
				JOptionPane.showMessageDialog(null, "NOT FOUND");
			}
		}
	}
 
	public void setId(int temp)
	{
		id = temp;
	}
 
    public int getID()
    {
    	return id;
    }
 
    public void setDate(String temp)
    {
    	date = temp;
    }
 
    public String getDate()
    {
    	return date;
    }
 
    public void setDescription(String temp)
    {
    	description = temp;
    }
 
    public String getDescription()
    {
    	return description;
    }
 
    public void setCopies(int temp)
    {
    	copies = temp;
    }
 
    public int getCopies()
    {
    	return copies;
    }
 
    public void setTitle(String temp)
    {
    	title = temp;
    }
 
    public String getTitle()
    {
    	return title;
    }
 
 
}

please help me out here. i added some comments in the code where im having trouble.

Originally Posted by Norm

Can you explain what trouble you are having? Post the full text of any error messages.
Make the calls to the Book class's methods before adding the Book class object to the arraylist.

Where does the code call the arraylist's add method?

i have no errors may my logic is wrong...
what do you mean by "Make the calls to the Book class's methods before adding the Book class object to the arraylist"?
it is in my main class, i did not post it because i thought it would be too long...

Originally Posted by Norm

        newBook.get(x).setId(newId);
	newBook.get(x).setDate(newDate);

What are these statements doing? It looks like they are calling the Book class's methods after the Book object has been added to the arraylist.


Can you explain what trouble you are having?

those statements are for storing the necessary info fro the book object in the arraylist. (i think)

my code cant seem to add the necessary info to my arraylist that's why i cannot retrieve it by using the retrieveItem method...

how should i do that?

the add method? you mean like this? "newBook.add(new Book(args))"???

newBook.addItem(Integer.parseInt(idTF.getText()), dateTF.getText(), descriptionTF.getText(), Integer.parseInt(copiesTF.getText()), 
    			titleTF.getText(), newBook.getAuthor(), newBook.getPublisher(), newBook.getIsbn());

thats my method of adding the necessary info the book needs to be added to my arraylist. it's in my my main class. and im using my addItem() method.

it is in the Book class. where in the Book class extends my library class. yes it compiles with no errors.

yes it should do that. It should create a Book object and store it in an array and the retrieveItem() method be able to retrieve what is store on the arraylist.

the addItem() is in the Library class, the user should add info first before adding it as a book object to the library class.