Implement Functionalities Of Set Class Using A Private Data Member Of Type ListReferencedBased
Feb 9, 2015
Okay, I am supposed to implement the functionalities of the Set class using a private data member of type ListReferencedBased<E>,how the ListReferenceBased works with what I am trying to accomplish.I am trying to complete Set.java, and I have barely started and much of the code doesn't work. ListReferenceBased was given to me completed.
import java.util.Iterator;
pubic class ListReferenceBased<E> implements ListInterface<E>, Iterable<E>{
/** reference to the first element of the list */
private Node<E> head;
/** number of items in list */
private int numItems;
public class StudentNumber { /* public StudentNumber(){ System.out.println("test"); } */ private char c='W'; public StudentNumber(float i){ System.out.println(i);
[Code] ....
Exception in thread "main" java.lang.RuntimeException: Uncompilable source code - c has private access in extention.pkgsuper.StudentNumber at extention.pkgsuper.ExtentionSuper.main
public class Class1 extends AbstractClass { //stuff } public class Class2 extends AbstractClass { //stuff }
within another class I have a private variable with the type of the Abstract class, and within one of the methods I assign an object to the the variable like this:
public class Test { private AbstractClass temp; public testMethod(){ Class1 anObject = new Class1(); temp = anObject; } }
Got a problem with generics, which I'm still pretty new at. Here's a program that compiles fine:
import java.util.ArrayList; import javax.swing.JComponent; public class Experiments { public static void main(String[] args) { ListHolder holder = new ListHolder();
[Code] ....
It's useless, but it compiles. If I change Line 14, however, to add a generic type parameter to the ListHolder class, Line 10 no longer compiles:
import java.util.ArrayList; import javax.swing.JComponent; public class Experiments { public static void main(String[] args) { ListHolder holder = new ListHolder();
[Code] ....
I get this error:
Uncompilable source code - incompatible types: java.lang.Object cannot be converted to javax.swing.JComponent at experiments.Experiments.main(Experiments.java:10)
Apparently, the introduction of the type parameter leaves the compiler thinking that aList is of type Object. I can cast it, like this:
JComponent c = ((ArrayList<JComponent>)holder.aList).iterator().next();
That makes the compiler happy, but why is it necessary? How does adding the (unused) type parameter to the ListHolder class end up making the compiler think the aList member of an instance of ListHolder is of type Object?
I am trying to implement product method below which returns the set representing the Cartesian product of the current set and a given set (the Cartesian product contains all ordered pairs (a, b) where a belongs to the current set, and b belongs to the given set). The product should be a ListSet <Tuple<E>> object where each ordered pair is a Tuple element. (I have a Tuple class which implements an ordered tuple)
What am I trying to do in the product method : Make 2 for loop and inside the for loop make an array of <E> then set the 2 elements of the tuple then again set tuple and add it to arrayList. how to set 2 elements of the tuple and set tuple ??
public class ListSet<E> implements Iterable<E>{ SinglyLinkedList<E> sl; public ListSet(){ sl = new SinglyLinkedList<E>();
I am trying to implement the following example to override the equality and hashCode method if the class has reference type member. I do get the expected result "true" for equal and "false" for non-equal objects. But the print statement in the Circle's equal method is not executed when the objects values are not equal. I don't know what i am missing, though i get the equality result "false" as expected for non equal objects.
class Point{ private int x, y; Point (int x, int y) { this.x =x; this.y = y;
i have two classes in two different files.i have this class:
Java Code:
public class Color { private int red; private int green; private int blue;
public Color(){ red = 0; green = 0; blue = 0; } mh_sh_highlight_all('java');
And i have this class :
Java Code:
public class Light { private Color color1; private boolean switchedon;
public Light(int red, int green, int blue){ //dont know what to write here . how can i use the members of the Color class here ? without using extends. } } mh_sh_highlight_all('java');
By using FileReader, FileWriter and their constituents, I am creating a file to contain employee information ( name, age, hours, etc. ). The user is to input all of the data on a single line and we were asked to implement StringTokenizer to assign that data to the file. I have never used the StringTokenizer before, but I have a rough idea how it is to function. I used pw.println to test what I have so far, now I would like to let the user build the initial file with the "first employees" of the company, and then view the file, and then go back and append new employee data to that same file. My question is, how can I take the user input as a StringTokenizer and add that to the file?
In the for loop below, I thought I would see if it would work, but it does not. The loop only executes once and does not allow me to enter data.
public class Records { public static void main(String [] args) throws IOException { Scanner input = new Scanner(System.in); FileWriter fw = new FileWriter("dbs3.java"); BufferedWriter bw = new BufferedWriter(fw); PrintWriter pw = new PrintWriter(bw); System.out.println("NEW EMPLOYEE DATA SHEET"); System.out.print("Number of new employees: "); int number = input.nextInt();
I want to implement a kind of "container" in which to store objects (instances) of different types. Then with an iterator I'd call common methods. This is what I have in mind:
Where translate(x, y, z) is a method common for objects in Positionables which objects are of different types (Sphere, Box etc.).
Now I was thinking Positionables could be a List<Positionable> and Positionable is an abstract class and Sphere and Box extends from it. But I don't know how to propagate the call of translate() to the subclasses.
What are the best approaches for this matter? It would be perfect if I could make it so I could somehow use the "with" construction like in the example above.
abstract class A class B extends A class C extends B class D extends C implements SomeInterface
I'm trying to implement a method "doSomething" declared in SomeInterface in class D. While trying to call doSomething in main I get the error message ”The method doSomething is undefined for the type B”
This is my code i main:
B container = new D("1,2,3,4,5,6,7,8"); System.out.println(container.doSomething());
I need container to be an object of type B, because it goes later into a list of type B. According to what I've been told, the only file I need to edit to make this work is class D.
I am trying to make a ChessBoard class composed of an array of JLabels inside a JPanel with a grid layout. I am also trying to override the getPreferredSize method so that the board will change size when I resize the main window (in another class in which I will instancize this class as part of a larger GUI). I got this kind of layout working before, but now I am trying to get it to work with multiple classes. However, after copying in the part of the previous code corresponding to the panel's layout, I am encountering some errors that I don't know how to solve. Specifically, when I try to override the getPreferredSize method, the compiler tells me "method does not override or implement a method from a super type, " and that it can't find the method "getPreferredSize"
Here's my code:
public class ChessBoard extends JPanel//the panel that this class extends is the boardHousing { //mental chess board piece array Piece mentalBoard[][] = new Piece[8][8]; //actual GUI chessboard JLabel Array static JLabel chessBoard[][] = new JLabel[8][8];
[Code] ....
I would just think that I was overriding the method incorrectly, but the weird thing is that I got that specific section of code to work before -- the only thing different now is that there are multiple classes, so my ChessBoard class itself is extending JPanel.
I'm working on a project that contains multiple classes. Each class contains and must contain only PRIVATE variables. Here's my issue. When my test code calls for a new instance of "StudentClass" as so:
StudentClass studentClass = new StudentClass(offeredClass.getClassIdNumber(), offeredClass.getClassName(), offeredClass.getClassroom());
The corresponding constructor won't let me initialize it's variables because they are declared private within another class, as shown here:
When getClassName, getClassroom, and getClassIdNumber are passed to a toString() method elsewhere in my test code. the output is returned just fine. When passed through the StudentClass, I'm getting Null across the board.
import java.util.Scanner; import java.util.ArrayList; public class Problem1 { public static void main(String[] args) { Scanner scan = new Scanner(System.in); ArrayList<String> list = new ArrayList<String>();
[Code] ....
There is an error and says that my ArrayList has private access. I can't figure out how to fix it.
The code runs but when I enter "Quit", the program just stops. The arraylist isn't printed out?
When creating a class with a constructor, why does one have to create private variables (attributes) to be used as parameters by the object? The object's parameters will be set to be exactly equal to the private variables (attributes), so what is the point of having the private variables (attributes) Why are both private variables (attributes) and parameters needed when they are set to be equal each other anyway?
1) When a variables are declared "Private" How should it be accessed from the driver class ? Sometimes i get an error in driver class saying "your variable is declared Private" why am I getting this error ...
The document says "Private" declared variables should be accessed only through methods. What does that mean.
I have a class named Base and a private variable named _hopcount i have 10 instances of class base i use _hopcount as creteria to some if but other instances edit _hopcount so i want to prevent _hopcount edit by other instances; I want to have private variable which other instances of same class can't modify it.
public class Base extends TypedAtomicActor { private int _hopcount = 0; if(_hopcount <= 3) { some code; } public function() { _hopCount += 1; } }
When we say derived class that means copy of base class plus subclass specific implementations. But when it comes to private members it cannot be accessible in subclass scope. Does it mean byte code generated for subclass doesn't has byte code of private members of super class ?
The String class stores the characters of the string internally as a private char[] and calling someString.length() results in getting the length field from the character array. I am looking to get the details on how the length is implemented. I understand it is a field, but in the original question I provide sample code and really want to know if/how the resulting byte code may differ when compiled, perhaps I am just not seeing the simple answer through my confusion.
If i have a class(lets say class name is Approval) with the following private members: String recip_id, Int accStat, String pDesc, String startDate How can i create public get and setter methods for these private members of the class?
