elvancedonzy :
I need to add three circle object into the Linked don't know where to start have basic knowledge of C++ new to java for about a month also basis in a data structure class in which we were giving this and modified it a little now we were told to add circles. I am thinking of creating an object class and injecting it into the LinkedBag, but how do i even go about it and will it display the circle or what?
Interface File
An interface that describes the operations of a bag of objects.
public interface BagInterface<T>
{
Gets the current number of entries in this bag.
@return The integer number of entries currently in the bag.
public int getCurrentSize();
Sees whether this bag is empty.
@return True if the bag is empty, or false if not.
public boolean isEmpty();
Adds a new entry to this bag.
@param newEntry The object to be added as a new entry.
@return True if the addition is successful, or false if not.
public boolean add(T newEntry);
Removes one unspecified entry from this bag, if possible.
@return Either the removed entry, if the removal.
was successful, or null.
public T remove();
Removes one occurrence of a given entry from this bag, if possible.
@param anEntry The entry to be removed.
@return True if the removal was successful, or false if not.
public boolean remove(T anEntry);
Removes all entries from this bag.
public void clear();
Counts the number of times a given entry appears in this bag.
@param anEntry The entry to be counted.
@return The number of times anEntry appears in the bag.
public int getFrequencyOf(T anEntry);
Tests whether this bag contains a given entry.
@param anEntry The entry to find.
@return True if the bag contains anEntry, or false if not.
public boolean contains(T anEntry);
Retrieves all entries that are in this bag.
@return A newly allocated array of all the entries in the bag.
Note: If the bag is empty, the returned array is empty.
public T[] toArray();
} // end BagInterface
______________________________________________________________________________________________________
//Class file
A class of bags whose entries are stored in a chain of linked nodes.
The bag is never full.
INCOMPLETE DEFINITION; includes definitions for the methods add,
toArray, isEmpty, and getCurrentSize.
public final class LinkedBag1<T> implements BagInterface<T>
{
private Node firstNode; // Reference to first node
private int numberOfEntries;
public LinkedBag1()
{
firstNode = null;
numberOfEntries = 0;
} // end default constructor
Adds a new entry to this bag.
@param newEntry The object to be added as a new entry.
@return True.
public boolean add(T newEntry) // OutOfMemoryError possible
{
// Add to beginning of chain:
Node newNode = new Node(newEntry);
newNode.next = firstNode; // Make new node reference rest of chain
// (firstNode is null if chain is empty)
firstNode = newNode; // New node is at beginning of chain
numberOfEntries++;
return true;
} // end add
Retrieves all entries that are in this bag.
@return A newly allocated array of all the entries in this bag.
public T[] toArray()
{
// The cast is safe because the new array contains null entries.
@SuppressWarnings("unchecked")
T[] result = (T[])new Object[numberOfEntries]; // Unchecked cast
int index = 0;
Node currentNode = firstNode;
while ((index < numberOfEntries) && (currentNode != null))
{
result[index] = currentNode.data;
index++;
currentNode = currentNode.next;
} // end while
return result;
// Note: The body of this method could consist of one return statement,
// if you call Arrays.copyOf
} // end toArray
Sees whether this bag is empty.
@return True if the bag is empty, or false if not.
public boolean isEmpty()
{
return numberOfEntries == 0;
} // end isEmpty
Gets the number of entries currently in this bag.
@return The integer number of entries currently in the bag.
public int getCurrentSize()
{
return numberOfEntries;
} // end getCurrentSize
// STUBS:
Removes one unspecified entry from this bag, if possible.
@return Either the removed entry, if the removal
was successful, or null.
public T remove()
{
return null; // STUB
} // end remove
Removes one occurrence of a given entry from this bag.
@param anEntry The entry to be removed.
@return True if the removal was successful, or false otherwise.
public boolean remove(T anEntry)
{
return false; // STUB
} // end remove
Removes all entries from this bag.
public void clear()
{
// STUB
} // end clear
Counts the number of times a given entry appears in this bag.
@param anEntry The entry to be counted.
@return The number of times anEntry appears in the bag.
public int getFrequencyOf(T anEntry)
{
return 0; // STUB
} // end getFrequencyOf
Tests whether this bag contains a given entry.
@param anEntry The entry to locate.
@return True if the bag contains anEntry, or false otherwise.
public boolean contains(T anEntry)
{
return false; // STUB
} // end contains
private class Node
{
private T data; // Entry in bag
private Node next; // Link to next node
private Node(T dataPortion)
{
this(dataPortion, null);
} // end constructor
private Node(T dataPortion, Node nextNode)
{
data = dataPortion;
next = nextNode;
} // end constructor
} // end Node
} // end LinkedBag1
_____________________________________________________________________________________________________
Other Class File
A test of the methods add, toArray, isEmpty, and getCurrentSize,
as defined in the first draft of the class LinkedBag.
public class LinkedBagDemo1
{
public static void main(String[] args)
{
System.out.println("Creating an empty bag.");
BagInterface<String> aBag = new LinkedBag1<>();
testIsEmpty(aBag, true);
displayBag(aBag);
String[] contentsOfBag = {"John Vex","Madam Teni", "Uncle Fireboy"};
testAdd(aBag, contentsOfBag);
testIsEmpty(aBag, false);
} // end main
// Tests the method isEmpty.
// Precondition: If the bag is empty, the parameter empty should be true;
// otherwise, it should be false.
private static void testIsEmpty(BagInterface<String> bag, boolean empty)
{
System.out.print("\nTesting isEmpty with ");
if (empty)
System.out.println("an empty bag:");
else
System.out.println("a bag that is not empty:");
System.out.print("isEmpty finds the bag ");
if (empty && bag.isEmpty())
System.out.println("empty: OK.");
else if (empty)
System.out.println("not empty, but it is: ERROR.");
else if (!empty && bag.isEmpty())
System.out.println("empty, but it is not empty: ERROR.");
else
System.out.println("not empty: OK.");
} // end testIsEmpty
// Tests the method add.
private static void testAdd(BagInterface<String> aBag, String[] content)
{
System.out.print("Adding the following strings to the bag: ");
for (int index = 0; index < content.length; index++)
{
if (aBag.add(content[index]))
System.out.print(content[index] + " ");
else
System.out.print("\nUnable to add " + content[index] +
" to the bag.");
} // end for
System.out.println();
displayBag(aBag);
} // end testAdd
// Tests the method toArray while displaying the bag.
private static void displayBag(BagInterface<String> aBag)
{
System.out.println("The bag contains the following string(s):");
Object[] bagArray = aBag.toArray();
for (int index = 0; index < bagArray.length; index++)
{
System.out.print(bagArray[index] + " ");
} // end for
System.out.println();
} // end displayBag
} // end LinkedBagDemo1
Abra :
Here is the Cirkle class that you need to create (as I wrote in my comment to your question). I named it Cirkle so as not to confuse it with other, existing classes named Circle that are part of the JDK library of classes. The class contains the radius of a circle and the X and Y coordinates of its center.
public class Cirkle {
private int centerX;
private int centerY;
private int radius;
public Cirkle() {
this(0);
}
public Cirkle(int radius) {
this(radius, radius);
}
public Cirkle(int radius, int center) {
this(radius, center, center);
}
public Cirkle(int radius, int centerX, int centerY) {
this.radius = radius;
this.centerX = centerX;
this.centerY = centerY;
}
public int getCenterX() {
return centerX;
}
public int getCenterY() {
return centerY;
}
public int getRadius() {
return radius;
}
public boolean equals(Object obj) {
boolean equal = false;
if (obj != null) {
Class<?> objClass = obj.getClass();
if (objClass.equals(getClass())) {
Cirkle other = (Cirkle) obj;
equal = radius == other.radius &&
centerX == other.centerX &&
centerY == other.centerY;
}
}
return equal;
}
public int hashCode() {
return (radius * 100) + (centerX * 10) + centerY;
}
public String toString() {
return String.format("Cirkle: radius = %d, center(%d, %d)", radius, centerX, centerY);
}
}
- Method
toString()is used to "display" aCirkleobject. - Method
equals()determines that twoCirkleobjects are equal if they both have the same radius and center. - Method
hashCode()is required when overriding methodequals().
Now you just need to replace the "bag" of strings in class LinkedBagDemo1 with a bag of Cirkles, as shown below in my modified version of the class that appears in your question.
public class LinkedBagDemo1 {
public static void main(String[] args) {
System.out.println("Creating an empty bag.");
BagInterface<Cirkle> aBag = new LinkedBag1<>();
testIsEmpty(aBag, true);
displayBag(aBag);
Cirkle[] contentsOfBag = new Cirkle[]{new Cirkle(5),
new Cirkle(5, 20),
new Cirkle(5, 100, 50)};
testAdd(aBag, contentsOfBag);
testIsEmpty(aBag, false);
}
private static void testIsEmpty(BagInterface<Cirkle> bag, boolean empty) {
System.out.print("\nTesting isEmpty with ");
if (empty)
System.out.println("an empty bag:");
else
System.out.println("a bag that is not empty:");
System.out.print("isEmpty finds the bag ");
if (empty && bag.isEmpty())
System.out.println("empty: OK.");
else if (empty)
System.out.println("not empty, but it is: ERROR.");
else if (!empty && bag.isEmpty())
System.out.println("empty, but it is not empty: ERROR.");
else
System.out.println("not empty: OK.");
}
private static void testAdd(BagInterface<Cirkle> aBag, Cirkle[] content) {
System.out.print("Adding the following Cirkles to the bag: ");
for (int index = 0; index < content.length; index++) {
if (aBag.add(content[index]))
System.out.print(content[index] + " ");
else
System.out.print("\nUnable to add " + content[index] + " to the bag.");
}
System.out.println();
displayBag(aBag);
}
private static void displayBag(BagInterface<Cirkle> aBag) {
System.out.println("The bag contains the following Cirkle(s):");
Object[] bagArray = aBag.toArray();
for (int index = 0; index < bagArray.length; index++) {
System.out.print(bagArray[index] + " ");
}
System.out.println();
}
}
And here is the output when I run class LinkedBagDemo1
Creating an empty bag.
Testing isEmpty with an empty bag:
isEmpty finds the bag empty: OK.
The bag contains the following string(s):
Adding the following strings to the bag: Cirkle: radius = 5, center(5, 5) Cirkle: radius = 5, center(20, 20) Cirkle: radius = 5, center(100, 50)
The bag contains the following string(s):
Cirkle: radius = 5, center(100, 50) Cirkle: radius = 5, center(20, 20) Cirkle: radius = 5, center(5, 5)
Testing isEmpty with a bag that is not empty:
isEmpty finds the bag not empty: OK.