How To Remove Item From ArrayList Then Add Back To Place Of Removal
Dec 2, 2014
How do you remove from an ArrayList at a particular index then add back to that same index without the removal causing the ArrayList to compensate for the loss of them item and moving the empty space to the end of the array list?I've tried:
public void dischargePatient(int bedNumber) {
if (bedNumber < beds.size()) {
beds.remove(bedNumber);
}
}
But this moves the bed at bedNumber to the end of the ArrayList after removing the patient from the bed. How do I keep it at bedNumber?
I'm trying to make a calendar that, when you click on the date, the result are stored in a map and visualized in a table that refers to a container.
I successfully created the map mechanism, but I have a problem on the list....
I add the rows in this way:
Object newItemId = container.addItem(); Item riga = container.getItem(newItemId); riga.getItemProperty("Timestamp").setValue(fara); riga.getItemProperty("Date").setValue(asa); . How can I delete a row in the list, when all I have in input is the "Timestamp" information, in a Long value?
I created a website using jsp and servlet. I made a shopping cart and got the items to display. But how can i remove the items from the cart? Next to each item is a remove button. When that is pressed the item selected needs to be removed and cart needs to refresh.
I have an ArrayList of tens of thousands of elements, and want to remove the items at a given set of sorted indices like {1,5,29,318,499,583}. It seems like this operation could be performed in linear time and space by first finding a cumulative sum of the shifts needed to move everything to their right positions and then shifting every item. On the other hand, removing and shifting one by one would seem to require many more shifts. Is there a way to do this in Java's ArrayList?
I have an array list in my GUI class of an aplication , the app reads in 3 fields from the user and saves these to an array list allowing the user to enter more fields to be added to the arraylist, when displaying back out to the user the same entry displays multiple times, for example if i entered , a,b,1 then c,d,2 and then e,f,3 into the app when i press my display button it would just throw back e,f,3 three times rater than the three different entries...
Constructor and instance variables
private String name; private String number; private int year; private int count; private ArrayList<StudentData> myList; private StudentData myData;
I managed to retrieve data, and set data in my own ways in which I like. But my problem is, if the file does not contain anything (fully empty), when I try to use my
set("", ""); method, it only sets the last one that is called.
and the corresponding snippets of the Java code are:
// Class member variables // ... private String product; private ArrayList<String> productValues; private ArrayList<String> productLabels; private SelectItem[] products; // ... Various properties etc. public String getLocation() { // Displayed on a page
[code]....
Most of this works correctly using only ArrayList SelectItem products without the two ArrayList and the separate SelectItem[], and the values and labels are put directly into products here. The menu works and I can select an item. However, I am unable to find the correct method for finding the index in the submit method,namely:
public void submit(ActionEvent e) { showProduct = true; prodNum = products.indexOf(product); // --- Here is the problem! updateProduct(); }
which has not been changed here. In spite of trying out various ideas, prodNum always returns with -1, which means it cannot find the index of the selected product, where product is a String. Everything else seems to work correctly, and products.get(prodNum).getLabel() works if I manually give prodNum a valid index, but because it's -1 it fails.
I managed to retrieve data, and set data in my own ways in which I like. But my problem is, if the file does not contain anything (fully empty), when I try to use my
When one is needed I simply add it to the table. In this case however whilst updating the model via table update in tableChanged method I have the impression of 2 identical models because the update happens twice (use of audio).
Is it not true that adding a new model cancels out the other ? I test for which model is attached to table and add the correct one depending on the data required.
I'm trying to find all of the prime factors for a given number. The following code achieves this:
private static ArrayList<Long> findPrimesOf(long number) { ArrayList<Long> primes = new ArrayList<>(); long highestDivisor = (long)sqrt(number); for (long divisor = 2; divisor <= highestDivisor; divisor++) { if (number % divisor == 0) { boolean isPrime = true; for (long i = 2L; i < divisor; i++) { if (divisor % i == 0) { isPrime = false; break;
[code]....
However, if I remove the boolean test isPrime, as below, I get additional numbers after the highest prime factor.
private static ArrayList<Long> findPrimesOf(long number) { ArrayList<Long> primes = new ArrayList<>(); long highestDivisor = (long)sqrt(number); for (long divisor = 2; divisor <= highestDivisor; divisor++) { if (number % divisor == 0) { for (long i = 2L; i < divisor; i++) { if (divisor % i == 0) { break;
[code]....
I can't work out why this should be. From my understanding, the divisor only gets added to the list of primes if the loop doesn't break (which, with the boolean test would be true anyway).
I noticed it is a huge success to have the backgrounds of games move and the character just move up and down and dodge obstacles.How Do I make a background that scrolls horizontally to the left? I know how to keep the character in place with up and down to move, but not sure how to go about making the background move with obstacles.
1. I read somewhere that instead of looping through every player (below), you use could Events to do it for you:
for (Player player : this.getPlayers()) { if (player.getLocation().getX() == 10) { } }
I'm not sure as to how to use Events in place of a for loop. I've been thinking on this for days, but I'm still stuck. Any example of using an Event instead of a for loop?
2. Is there any way to accept multiple connections on a server without using a while loop? Maybe use Events to handle the acceptance of connections?
Is it possible to enable & disable "jdk.certpath.disabledAlgorithms" property programmatically. I want to remove all disabled Algorithms for some time and later I will enable it.
Or is it possible to enable only for a particular place & not in a JVM level. I want that Algorithm need to be enabled for a piece of code, but I don't want it to the remaining part of the application.
I am making a Dice Roll GUI and I have most of it down and I only need this constructor to work for the program to work (I think). I don't know where to place the constructor, I tried placing it around the RollButton class but it still didn't work and gave me java error constructor in class cannot be applied to given types
Here's my constructor:
private JPanel panel; public RollButton(JPanel panel){ this.panel = panel; }
I am currently trying to solve a programming problem on this site, and the problem includes working on a 100 digits of decimal places of a certain irrational number. I tried using BigDecimal class but it displays, correctly me if I am wrong, just 20+ decimal digits. Is there other way to do this?
I am trying to convert the double grossPay to 2 decimal places but cannot get it to work ,I am unsure of the correct way of doing this but this is how far I can get
for standard deviation my output is not rounded to the 10's place, how can I make it round to the 10's place. Here is my code.
import java.util.*; public class chapter7 { public static final int Max_Number_Scores = 100; public static int fillArray(double[] scores) { System.out.print("You entered "); for (int i = 0; i < scores.length; i++) { System.out.print(scores[i] + " ");
I've been putting together an addressbook and try to work on some idea but I have hit a bit of a wal early on, and Im sure the problem is easy to resolve, I just can't get the old brain to do it.At present I have 5 classes
I have taken EnterDetailsPanel out of the main GUI code, as I plan, or had planned on using additional JPanels for the other options of the application until I got stuck. What I want the EnterDetails panel to do, which it does so far is to have the user enter all of their information and when the button is pressed it will then create a PersonDetails object and here is where my problem is. how to get the object from the panel back across to the GUI which initalises the AddressBook class in the constructor and add it to the List via an addDetails() method.
If I create a quick method in the AddressBookGUI class I can add the object to the List fine, I'm guessing this is because I have created a new instance of the AddressBook in here already via the constructor, however if I add an AddressBook reference in the EnterDetailsPanel I get a nullpointerexception for the opposite because it's not been created in there.These are what most of the classes do so far.
PersonDetails has a reference to the AddressDetails and holds all information for that person.AddressBook contains a List that accepts PersonDetails and has methods to add/remove the person.AddressBookGUI creates a new instance of the AddressBook class along with the general gui things. EnterDetailsPanel is added to JTabbedPane in the GUI class and allows the user to enter their details and submit those via a button which will then create a new PersonDetails object that I am trying to get added to the AddressBook class List
I am trying to figure out how to get information back from a different method.
Basically I want to write a program to create a car, but I want to be able to add features based on user our put (V6 versus V8, Color choice, etc), but I want each one to be broken out into their own method but I am unsure of how to call from the main method and return the variable (engineSize = V8, color = blue, etc).
I'm not sure why, but whenever I try to get a value out of a double, it only extends to one decimal place. For instance, (825 / 805) would become 1.0000 (after being run through a DecimalFormat object) instead of 1.0248 like I need it to be (and should be if what I know about primitive variable types is right). Why is the double variable type not giving me the precision I want and, more importantly, how do I fix this?
