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Java Collection Q&A » ArrayList » object 2 

1. ArrayList objects    forums.oracle.com

2. Access ArrayList of Objects    forums.oracle.com

3. Help with ArrayList of Objects    forums.oracle.com

if (book.getBorrowerNumber() == borrower && book.getBorrowerNumber() != 0){ searchNumber++; System.out.println(searchNumber + " " + book.getDescription());} The problem is now that once I done the search, if only generates one book, i should be able to change the borrower number of that specific book. so the previous methods continous like that: if(searchNumber == 1 ){

4. Accessing ArrayList object    forums.oracle.com

What I want to do is call the getGallonsSold() method on the first (0) object of the myPumps array list. The myPumps arraylist contains several "pumps" at a "gas station", and I'm trying to get the amount of gallons sold for the first pump at the station. However, I think I'm a bit confused on how to do it! Thanks for ...

5. comparing objects in an ArrayList    forums.oracle.com

Hi everyone! I have an ArrayList of objects that have String parts. For example, the list contains Courses that have String names so it would be like course1.name I need to check that a different Course being added to the list does not have the same name as one of the other courses already in the list. I tried using a ...

6. Error on adding object to arrayList    forums.oracle.com

9. having trouble with an Object ArrayList    forums.oracle.com

I am currently trying to access data inside an Object ArrayList which I have populated from a file using an ObjectInputStream. I do not want to move the data into an array, I would prefer it if I could access the data directly from the ArrayList but so far have found no methods that can do this. I have used the ...

10. comparing arraylists objects    forums.oracle.com

Take a look at the [Comparable.compareTo|http://download.oracle.com/docs/cd/E17409_01/javase/6/docs/api/java/lang/Comparable.html#compareTo%28T%29] method. Notice that it takes an argument. Your compareTo() method does not take an argument. If you implement Comparable, you have to have a compareTo method that takes an argument. That's what the compiler is telling you. How would it make sense to have a compareTo method that takes no argument? Edit- Now you're trying ...

11. Problem of reference from an object added to an ArrayList    forums.oracle.com

Calling add() does not copy the object you're adding. It just places a reference to it in the List. So then when you call add() again, passing another reference to the same object, both elements in the List point to the same object. Then when you change that object's state, both List elements see the change. This is not specific to ...

12. A question about ArrayList and Object    forums.oracle.com

I have an arraylist 'dato'. I want that it save a String arrays Why is the reason because 1 runs ok and 2 not ? 1.- Runs ok ArrayList dato = null; String [] pepe={"0xx0", "0x1", "0x2", "0x3"}; dato.add (pepe); 2.- Fails ( "AWT-EventQueue-0" java.lang.NullPointerException ... ) dato.add(new String []{"0xx0", "0x1", "0x2", "0x3"}); How can I write a short line like ...

13. How to exclude exisiting objects when combining ArrayLists?    forums.oracle.com

Thanks for your reply I tried using a HashSet, which works for removing objects from the same origin, but it doesn't seem to remove the same data when added to the ArrayList from different objects. For example, id like to use cs1 to remove an instance of cs2 as they contain the same data but are assigned using different objects.

15. Comparing two objects in an Arraylist by a specific attribute    forums.oracle.com

Hello all, I'm a beginner Java programmer and I'm looking for a way to compare two objects that are stored in an Arraylist by a specific attribute. For example, if I have an arraylist with objects in it, and every object has its own name, age, weight, whatever stored. Is there an easy way to take two specified objects, and then ...

17. Arraylist of objects    forums.oracle.com

do { String a = newtoken.nextToken(); String b = newtoken.nextToken(); Course c = new Course(a,b); // <<<----- How do i create a new object every pass thru the loop?? System.out.print(a); // test--- prints out all courses ok System.out.println(b); //test--- prints out all courses ok list.add(count,c); count = count + 1; } while (newtoken.hasMoreTokens());

18. How to transfer/remove objects safely between ArrayLists    forums.oracle.com

Think of things this way, you are dealing with references to objects and not the object itself. So if you create an object A and put that object into two separate lists, you are actually referencing this object from both lists. So if you remove the object from one list, you are removing the reference to that object from that one ...

19. Retrieving an Object from an ArrayList.    forums.oracle.com

} } My problem lies in the UpdateWebPage() method. I have a line within the method, shown below; int position = WebPages.indexOf(new WebPage(url)); Which should give me the position of a WebPage object via its url, passed as a string. However when I run the program, I found the value -1 is returned which I believe means the parameter has not ...

20. Searching an arraylist for user defined objects    forums.oracle.com

Hi friends, I have an array list of employee(empId,empName,salary,deptId) objects. I want to get sublist of employees having deptId as n. I also want to find the max(salary) of employee in each departement. This is similar to sql : select deptId,max(salary) from employee group by deptId. Please find me a solution. Thanks in advance.

21. sending method objects to an arraylist    forums.oracle.com

Also, 1 of the reason to why it wont work is because your method dealCard(), doesnt return anything, so how do you expect to add that to and ArrayList? There are other faults that can be spotted as well. But you need to post an complete runnable program, that you can work with and share. Just showing this little code, without ...

22. How to access an Arraylist object from a separate class?    forums.oracle.com

What's your question? If I understand your code correctly, that's a way to accomplish what you're talking about. Other than items not being a method. Only methods get ( ) after them, variables don't. PS- It would help you if you used more meaningful variable names. Like "listOfThings" instead of "hello". Just a suggestion.

24. Adding objects to a global arraylist    forums.oracle.com

25. Comparing objects in arraylist    forums.oracle.com

26. stuck on arraylist of object class    forums.oracle.com

27. arraylist group of objects    forums.oracle.com

28. Using an Arraylist to draw objects    forums.oracle.com

29. arrayList object detail retrieval    forums.oracle.com

Thanks puckstopper31, that solution is more appropriate to what I require so will give it a go. Thanks newark, I thought that too but for some reason assumed that each instance would be treated separately by it's index. In a way, this helps me to realise how dynamically the objects are treated by java. Thanks again!

30. ArrayList Object    forums.oracle.com

Hello all. I'm creating an ArrayList that is full of strings and I'm wondering if there is a way to match ArrayList text to a String. For example I use a for loop to go through the ArrayList, and I am performing a search for a certain text. Is there a way that I can use a ".instanceof()" method for my ...

32. Loading object to ArrayList, java IO    forums.oracle.com

33. How to create an object from an arrayList    forums.oracle.com

34. ArrayList With Diffrent Objects Question...    forums.oracle.com

Hi, Got a question/problem. Basically I have and ArrayList general called fixedTimeBlocks with contains different types of objects such as: lectureTimeBlock courseworkTimeBloc seminarTimeBlock examTimeBlock This fixedTimeBlock's ArrayList represents a "time line" with the "time blocks" placed within the fixedTimeblock's ArrayList according to there time. Where my problem lies is when I search through the ArrayList I am looking to see if ...

36. Associate object in one ArrayList with object in another ArrayList    forums.oracle.com

Hi, I have 2 ArrayLists: "storeArray" which stores "Store" objects. "itemArray which stores "Item" objects. The store object has properties of "int storeNumber" and "String storeName". The item object has properties of "int itemNumber" and "String itemName". I wish to associate an object in storeArray with an object in itemArray. For example, item(101, Coke) in itemArray can be found in stores ...

37. Confused about objects in ArrayLists    forums.oracle.com

/*if (input.equalsIgnoreCase("I")){ System.out.println("Enter player's last name: "); String lastNameInfo = keyboard.nextLine(); for (int i=1; i

38. update an object existing in an ArrayList    forums.oracle.com

39. check if an object exists in an ArrayList    forums.oracle.com

40. i need help with comparing Objects of an ArrayList    forums.oracle.com

return result; } could you just let me know whether the method looks ok or should make changes to it. Now i dont know how i should use this method to compare a new created AuctionBid to those AuctionBid objects which already exist in the arrayList. do I have to make a loop and iterate through every single object in the ...

41. PIcking random objects from arraylist    forums.oracle.com

Hi all, Got a quick question. I'm trying to get objects from an arraylist that contain int and String types, randomly "shuffle" them within the servlet, display them one at a time to the JSP page, and then have a button on the JSP page that will pull the next object from the arraylist to display on the same JSP page. ...

42. arraylists with objects    forums.oracle.com

I am currently taking a IB computer science class in high school and I just have a quick question, probably an easy one. So were making a mini yahtzee game, with three dice instead of one, and we have to incorporate our own die class with an arraylist for the dice. I have made the arraylist one without using the die ...

43. Getting an Object out of ArrayList    forums.oracle.com

Hello, I have a question about getting an Object out of an ArrayList. I have an object that's made up of four fields: name, average, total and position. Now, I need to read in values from a formatted text file, and stick those values into an array (the values correspond to the Object values), but since there's a variable number of ...

44. ArrayList help, regarding objects in ArrayLists    forums.oracle.com

I have got the loop but it's my first time using an enhanced for loop so I wouldnt know how to use it. Unlike the normal for loop with i as and index. I can just use i to manipulate the data freely. But the loop that you gave me, i doubt i can understand it fully. All i know is ...

45. create object's class arraylist    forums.oracle.com

46. Help with accessing objects in ArrayList    forums.oracle.com

47. Arraylist issue: pass all the arrayList `s object to other arrayList ...    forums.oracle.com

I'm not sure if this will help or not but you have to remember that the ArrayList(s) don't actually contain your Objects. They contain references to Objects. So if you copy a reference from one ArrayList to a second ArrayList, they both contain a reference to the same Object. If this doesn't help, you need to provide more information about what ...

48. how to save all the arrayList`s object??    forums.oracle.com

49. Changing Objects attributes from an ArrayList    forums.oracle.com

The problem is that the variable index is not set properly in search(). In the loop while(index < books.size()){ ...... index++; } you keep on incrementing the index even if you have found the book. Thus the index is always equal to books.size() after the completion of loop. You could break from the loop as soon as you get the book ...

50. Get Object[] length in ArrayList    forums.oracle.com

I definitely dont need to. At least not for my program. I have 100,000 Lists (holding 300,000 objects). Just out of curiosity I wanted to see how much bigger the capacities were than the size given that "the details of the growth policy are not specified". Even if the capacity was double thats only 1 MB so im not concerned. I ...

51. Adding objects to an ArrayList    forums.oracle.com

52. Query regarding an ArrayList object    forums.oracle.com

Kajb,I had downloaded this around 3 years ago and this printed in front of me. This was an article on the Java Sun Site Using Collections with JDK 1.2 by Glen McCluskey (1998) and the first example he is showing is using this ArrayList example. 1.5 wasnt in the market 3 years ago and the date on the above examples date ...

53. object in Array list    forums.oracle.com

at the moment i have two file one called Book & another Called Home Books Class has Addbooks (); Dispaly Books() Borrow Books(); Return Books(); Welcome();// to Display MENU LIST Home class has main method() object for class Books object store books data when a book is added and Array list to store objects... problem is can't display array list...

54. Adding objects to an arrayList    forums.oracle.com

Hello all, i appreciate your replies. I am still having troubles with this part of my program, i have tried the code provided, but i think this is too complicated for me. Is it possible to go into more detail? Please remember the .dat file has a number first, followed by names and addresses. Cheers

55. ArrayList returns objects of type "Object"    forums.oracle.com

as long as your class doesn't use ArrayList thru inheritance that is fine, altho perhaps overengineered. Usually you will have a class that is responsible for the contents of the arraylist field. It is that class's job to ensure the list's integrity. Usually that class wouldn't even want to let clients of itself know that it has such a member field. ...

56. ArrayList Reference VS Object    forums.oracle.com

Your tempProdList is populated with references to the same objects as currentGroupProducts. This is why changes using such a reference to a Product are visible via both ArrayList's. What you seem to want is to polulate tempProdList with references to copies of the Product objects found in currentGroupProducts. You will need to iterate through currentGroupProducts elements, clone them one by one ...

57. How can I add Objects in ArrayList?    forums.oracle.com

package myproject_diary; import java.util.*; import javax.swing.*; public class MyProject_Diary { public static class Project implements Diary { private String Name; private String Address; private String PhoneNumber; private String Email; public Project() { Name=""; Address=""; PhoneNumber=""; Email=""; } //**********************************FUNCTIONS*********************************** @Override public void Add() { this.Name=JOptionPane.showInputDialog("Enter Name "); this.Address=JOptionPane.showInputDialog("Enter Address "); this.PhoneNumber=JOptionPane.showInputDialog("Enter PhoneNumber "); this.Email=JOptionPane.showInputDialog("Enter Email Address "); } @Override public void Deleete(String ...

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