If I set a Jlist to contain an array of objects, how can I display properties of each object instead of the object array list itself. Ex:
Instead of:
Person1
Person2
Person3
display values such as each person name within the Jlist:
Mike
Paul
Andrew
I am trying to find either some references to point me on the right track with passing an object with all of it's properties still in tact after it's been created. Currently I am trying to do this through an interface but it seems to just create a new object everytime without the properties. Example below :
import java.util.ArrayList;
import java.util.List;
public interface TPerson{
//public Person p = null;
}
class Thrower {
Person p;
[code]....
When I implement the interface on the other objects as soon as I call the setP method shown above it seems to just create a new one even though I pass the object to the method I want to use.
I am new to Java and have read books, the Java docs, and searched the Internet for my problem to no avail. I have an Array of objects that contains strings. How can I get the object's strings to print in a list so that the user can select that object to manipulate its attributes? For example, the user can select "Guitar 1" from a list and manipulate its attributes like tuning it, playing it, etc. I have a class called Instruments and created 10 guitar objects.Here is the code:
Instrument [] guitar = new Instrument[10];
for (int i = 0; i < 10; i++) {
guitar[0] = new Instrument("Guitar 1");
guitar[1] = new Instrument("Guitar 2");
guitar[2] = new Instrument("Guitar 3");
guitar[3] = new Instrument("Guitar 4");
guitar[4] = new Instrument("Guitar 5");
guitar[5] = new Instrument("Guitar 6");
[code]...
I have just started working with linked lists. I have a linked list of Objects and I want to be able to search for a specific object. But currently my code continues to return false. Also how would I go about removing the first index of the linked list.
public static void main(String[] args) {
LinkedList<Cookies> ml = new LinkedList<>();
int choice = 0;
while (choice >= 0) {
choice = menu();
[Code] ....
Suppose that you have an ArrayList and that it contains String objects. Which declaration of the ArrayList requires that objects retrieved using the get method be cast to Strings before calling a String method?
I. ArrayList a = new ArrayList();
II. ArrayList<Object> a = new ArrayList<Object>;
III. ArrayList<String> a = new ArrayList<String>;
A. I only
B. II only
C. III only
D. I and II only
E. I, II, and III
I know that all of these are ways to declare an Array List, but I am unfamiliar with the last two since I usually just declare my Array Lists with the first option.
I am parsing an XML file. i.e.
<people>
<person firstname="John" lastname="Doe" age="50" />
<person firstname="Thomas" lastname="Jefferson" age="260" />
<people>
I have created Person.java with the following attributes:
private String firstName;
private String lastName;
private int age;
My main method parses the XML, loops through each person, and gets the attributes for each.
I need to create instances of my Person class. I could write something like this:
Person person = new Person();
for (int i = 0; i < attributes.getLength; i++) {
if (attribute.getName(i) = "firstname") { person.firstName = attribute.getValue(i);}
if (attribute.getName(i) = "lastname") { person.lastName = attribute.getValue(i); }
if (attribute.getName(i) = "age") { person.age = attribute.getValue(i); }
}
Since my actual XML has quite a few attributes, I would rather do something like this:
Person person = new Person();
for (int i = 0; i < attributes.getLength(); i++) {
person[attribute.getName(i)] = attribute.getValue(i);
}
This doesn't work.
I am having a little trouble with a part of my Java assignment that needs to have linked lists in it.
I need to write a public method that takes an array of type object to load strings into a linked list.
I am having trouble with a mouse click method. In short I have a hexagon grid, and every time I want to click on one particular hexagon I want the color of the hexagon to change to blue(by default the color is grey). This part works, but when I go to click on another hexagon I want the color of the previous hexagon to change back to grey while at the same time changing the color of the current hexagon clicked to blue. So in other words, I only want one hexagon blue at a time. How might I do this?
I have a hexagon class for one particular hexagon, and a hexmap class for multiple hexagons. I know I should probably be handling mouse clicks in the hexmap since it deals with the whole thing. But I cannot say something like hexagon.setColor within a mouselistener in that class(it gives me a lot of issues). Here is some of my code :
public class Hexagons()
public Hexagons(HexMap theMap, int mapRow, int mapCol, int width, int height) {
this.map = theMap;
this.row = mapRow;
this.col = mapCol;
this.width = width;
this.height = height;
[Code] ....
In my project I need to create a pizza ordering system. I have created a array list of pizza toppings and each pizza topping must have a cost property associated with it, then the user can pick the toppings they want and the cost of each topping will be added up and the total cost of the whole pizza will be displayed. But I don't know how to associate a cost with each topping. I have been told that I can access the cost through a get/set method and store it in a private member variable. But I don't know how to do this?
I've tried to do it, but it hasn't worked. This is the code
public void setCost( double cost){ //my get/set method
this.cost = cost;
}
public double getCost(){
double price = 0;
return price;
[Code] .....
But there is an error on each of the ingrediantCost method lines, saying
The primitive type double of cost does not have a field Pepperoni
...and the same for chicken, ham and onion.
I have some class called sorted to sort the linked list through the nodes of the list. and other class to test this ability, i made object of the sort class called "list1" and insert the values to the linked list.
If i make other object called "list2" and want to merge those two lists by using method merge in sort class. And wrote code of
list1.merge(list2);
How can the merge method in sort class know the values of list1 that called it as this object is created in other class.
Create an equals method that takes an object reference and returns true if the given object equals this object.
Hint: You'll need 'instanceof' and cast to a (Geocache)
So far I have:
public boolean equals(Object O){
if(O instanceof Geocache){
Geocache j=(Geocache) O;
if (this.equals(j)) //I know this is wrong... but I can't figure it out
return true;
}
else return false;
}
I think I have it correct up to the casting but I don't understand what I'm suppose to do with the this.equals(). Also I'm getting an error that I'm not returning a boolean... I get this all the time in other problems. I don't get why since I have to instances of returning booleans in this. "returns true if the given object equals this object" makes no sense to me. I assume the given object, in my case, is 'O'. What is 'this' object referring to?
I am trying to get an object to display twice from a class in an applet.
Java Code:
if (label == 4) {
game.stop();
timer.start();
result.setText(" You Have Destroyed the World");
marFoundDisplay.setText("Martian: " + String.valueOf(mCount));
jupFoundDisplay.setText("Jupiterian: " + String.valueOf(jCount));
highScoreDisplay.setText("HighScore : " + String.valueOf(HighScore));
j.draw(g, 350, 150);
j.draw(g, 350, 150); mh_sh_highlight_all('java');
Obviously calling it twice doesn't get the desired effect, I'm ultimately trying to get them to be side by side in the middle of the applet, but clearly what I've done won't achieve that.Can you provide me an example that would allow me to display the code below to have the item be displayed twice side by side?
Java Code:
j.draw(g, 350, 150); mh_sh_highlight_all('java');
first i looked at this example and understand this fine:
import java.util.ArrayList;
import java.util.Iterator;
public class Main {
[Code]....
I'm facing a problem in below scenario:
List lst = tDAO.executeReport();
lst contains list of objects and one of the objects contains the property bDate(Timestamp) which has the value 28-2-1989 00:00:00.0, now I just wants to change the value into 28-2-1989 and store it back into the List as a Timestamp. how can I do that.
I am following those three tutorials and I have completed it with success.
( [URL] .... )
( [URL] .... )
( [URL] .... )
But then, as author haven't implemented removeCountries method I tried to create it. What I did initially was to just add to class Countries this method:
public boolean removeCountry(Country country) {
return countries.remove(country);
}
But although compiler wasn't complaining it didn't work. Actually it worked last night (before reboot) but not today. Must be some SOAP iterator/binding thing or whatever. Or I thought that it worked but in fact it didn't.
Here are original classes:
//-------------------------------
public class Country {
String CountryId;
String CountryName;
public Country() {
super();
[Code] ....
I would like to avoid my own iterator as JDeveloper can generate automatically iterators for webservices, but if I can't get it that way, what would be better way to write above mentioned iterator in removeCountry method?
Is there any way to remove object directly with something like this:
co.countries.remove(o);
co.removeCountry(country)
using method
// This left unused
public boolean removeCountry(Country country) {
return countries.remove(country);
}
from class Countries?
Parameters should be set by web service iterator.
I want to create a program where I need to create an object of list type such as text file will contain nos like 1,2,3,4,5 and write into text file and delete the in FIFO order i.e 1,2,3,4,5...how i can achieve to write a program? I tried bt everytime got concurrent modification exception or Array out of bound exception.
View Replies View RelatedI am trying to put a reference to a given subclass object into a linked list, and then come back later, and invoke a method of the subclass object that is in a given spot in the linked list. This produces an error because Object does not have that method. Is it necessary to cast the object to the correct subclass every time I want to use one of its methods, or is there a way to convince the JVM to treat it as always of type MySubclass?
View Replies View RelatedHow to use the id parameter in my documents entity to download documents from a list of documents. Normally I use ListDataModel and the getRowData method. I would like to know how to achieve the same thing using an ordinary List object.
My list of documents is called List<CountryDocs> selectedDocs;
<h:form>
<p:dataTable value="#{countryDocBean.selectedDocs}" var="docs">
<p:commandLink id="download" value="Download" ajax="false">
<p:fileDownload value="#{countryDocBean.downloadedFile}"
contentDisposition="attachment"/>
[Code] ....
Clicking on the download link calls the following method in my managed bean:
@ManagedBean(name = "countryDocBean")
@SessionScoped
public class CountryDocBean {
private List<CountryDocs> selectedDocs;
public StreamedContent getDownloadedFile() {
[Code] ....
Debugging shows the value for the id is 0 and this results in a NullPointerException. I've tried several methods for grabbing the document id in my backing bean, but no luck yet. I also read about the the ViewParams and ViewAction method but they caused validation errors to do with the <f:metadata> tags. I don't know how to obtain this value using a normal List object.
I am using Java 1.6, I have this class ....
import java.util.ArrayList;
import java.util.List;
public class TestDrive
{
public TestDrive()
{
super();
[Code] ....
What is the most efficient way to group the preferences of the same type, In other word I want just a print statement to print this line.
BREAKFAST(Eggs,Milk),SPORTS(Basket,Tennis),....
For this program I am calculating the annual costs of 5 office supplies (user input) each with a 5.7% inflation. The user inputs the cost of each object and my program must calculate and display the price of each object each year for 5 years. I already have this part. What I need is how to add the total costs of all 5 supplies per year and display each total cost. Here is the program:
import java.util.Scanner;//Using keyboard to enter data
//Start of Class
public class OfficeSupplyCalculator {
//Start of Method
public static void main(String args[]) {
Scanner keyboard = new Scanner(System.in);
System.out.println("Enter the first item");
[Code] .....
At the moment all I get for the grand total loop is the same number showing up 5 times. I feel like the problem is how I am declaring the grandtotalperyear variable but I'm not sure what is wrong.
can a keyevent in java make the space ship and the laser too ?
View Replies View RelatedFor example I create an object like this:
BankAccount b = new SavingsAccount();
Now lets say that I want to access a method 'addInterest()' that is in the 'SavingsAccount' class I would have to do: '((SavingsAccount)s).addInterest();'
The question I have is why do I have to cast 'b' to SavingsAccount? Isn't the actual object reference of 'b' already an instance of 'SavingsAccount' class? How does the 'BankAccount' affect the object itself? I'm really confused as to what class is truly getting instantiated and how BankAccount and SavingsAccount are both functioning to make the object 'b'.
I don't understand why the object reference variable 'a' cannot be recast from a thisA object reference to a thisB object reference.Is it the case that once a reference variable is linked to a particular object type then it cannot switch object types later on.I am facing the Java Associate Developer exam soon and I am just clearing up some issues in my head around object reference variable assignment,
class thisA {}
class thisB extends thisA { String testString = "test";}
public class CastQuestion2 {
public static void main(String[] args) {
thisA a = new thisA();
thisB b = new thisB();
[code]....
I am trying to get this to where I can type in a name and it will search through each object and print back the corresponding object info.
Java Code:
import java.util.Scanner;
public class MyPeople {
public static void main(String[] args) {
Person[] p = new Person[] {
new Person("Chris", 26, "Male", "NJ", "Single"),
new Person("JoAnna", 23, "Female", "NJ", "Single"),
new Person("Dana", 24, "Female", "NJ", "Single"),
new Person("Dan", 25, "Male", "NJ", "Single"),
new Person("Mike", 31, "Male", "NJ", "Married") };
[code]....
Task:The main method of the class Things below creates an object called printer deriving from the class PrintingClass and uses that object to print text. Your task is to write the PrintingClass class.
Program to complete:
import java.util.Scanner;
public class Things {
public static void main(String args[]) {
String characterString;
Scanner reader = new Scanner(System.in);
PrintingClass printer = new PrintingClass();
System.out.print("Type in the character string for printing: ");
characterString = reader.nextLine();
printer.Print(characterString);
}
}
// Write the missing class here
Note: In this exercise the solution is part of a conversion unit where many classes have been declared. Because of this the classes are not declared as public using the public attribute.
Example output
Type in the character string for printing: John Doe
John Doe
My Class:
class PrintingClass {
public void print(){
System.out.println(characterString);
}
}
I have an Array of objects that contains strings. I am new to Java and have read books, the Java docs, and searched the Internet for my problem to no avail. How can I get my strings to print in a list so that the user can select an object to manipulate its attributes? I have a class called Instruments and created 10 guitar objects. Here is the code:
Instrument [] guitar = new Instrument[10];
for (int i = 0; i < 10; i++) {
guitar[0] = new Instrument("Guitar 1");
guitar[1] = new Instrument("Guitar 2");
guitar[2] = new Instrument("Guitar 3");
guitar[3] = new Instrument("Guitar 4");
[Code] ....