Answer Happy

HERE IS A JAVA FILE FOR LINKED BAG. NEED TO DO ALL of the //TODO sections. There are 3:
equals, removeDuplicatesOf, and removeAllDuplicates. They are in BOLD at the end of the question. LINKED BAG.
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public final class LinkedBag<E> implements BagInterface<E> {
private Node head;
private int size;
public LinkedBag() {
head = null;
size = 0;
}
/**
* Sees whether this bag is empty.
* @return True if this bag is empty, or false if not.
*/
@Override
public boolean isEmpty() {
return size == 0;
}
/**
* Gets the current number of entries in this bag.
* @return The integer number of entries currently in this bag.
*/
@Override
public int getCurrentSize() {
return size;
}
/**
* Adds a new entry to this bag.
* @param newEntry The object to be added as a new entry.
* @return True.
*/
@Override
public boolean add(E newEntry) {
Node newNode = new Node(newEntry, head);
head = newNode;
size++;
return true;
}
/**
* Retrieves all entries that are in this bag.
* @return A newly allocated array of all the entries in this bag.
*/
@Override
public E[] toArray() {
// the cast is safe because the new array contains null entries
@SuppressWarnings("unchecked")
E[] result = (E[]) new Object[size]; // Unchecked cast
int index = 0;
Node currentNode = head;
while ((index < size) && (currentNode != null)) {
result[index] = currentNode.data;
index++;
currentNode = currentNode.next;
}
return result;
}
/**
* 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 this bag.
*/
@Override
public int getFrequencyOf(E anEntry) {
int frequency = 0;
int loopCounter = 0;
Node currentNode = head;
while ((loopCounter < size) && (currentNode != null)) {
if (anEntry != null && anEntry.equals(currentNode.data)) {
frequency++;
}
loopCounter++;
currentNode = currentNode.next;
}
return frequency;
}
/**
* Tests whether this bag contains a given entry.
* @param anEntry The entry to locate.
* @return True if this bag contains anEntry, or false otherwise.
*/
@Override
public boolean contains(E anEntry) {
boolean found = false;
Node currentNode = head;
while (!found && (currentNode != null)) {
if (anEntry != null && anEntry.equals(currentNode.data)) {
found = true;
} else {
currentNode = currentNode.next;
}
}
return found;
}
/**
* 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.
*/
@Override
public boolean remove(E anEntry) {
boolean result = false;
Node nodeN = getReferenceTo(anEntry);
if (nodeN != null) {
nodeN.data = head.data; // Teplace located entry with entry
// in first node
head = head.next; // Remove first node
size--;
result = true;
}
return result;
}
// Locates a given entry within this bag.
// Returns a reference to the node containing the entry, if located,
// or null otherwise.
private Node getReferenceTo(E anEntry) {
boolean found = false;
Node currentNode = head;
while (!found && (currentNode != null)) {
if (anEntry != null && anEntry.equals(currentNode.data)) {
found = true;
} else {
currentNode = currentNode.next;
}
}
return currentNode;
}
/**
* Removes all entries from this bag.
*/
@Override
public void clear() {
while (!isEmpty()) {
remove();
}
}
private class Node {
private E data; // Entry in bag
private Node next; // link to next node
private Node(E dataPortion, Node nextNode) {
data = dataPortion;
next = nextNode;
}
}
/**
* Removes one unspecified entry from this bag, if possible.
* @return Either the removed entry, if the removal was successful, or
* null.
*/
@Override
public E remove() {
E result = null;
if (head != null) {
result = head.data;
head = head.next;
size--;
}
return result;
}
/**
* Override the toString() method so that we get a more useful display of
* the contents in the bag.
* @return a string representation of the contents of the bag
*/
@Override
public String toString() {
StringBuilder result = new StringBuilder("Bag[ ");
Node scout = head;
for (int index = 0; index < size; index++) {
result.append(scout.data.toString());
result.append(' ');
scout = scout.next;
}
result.append(']');
return result.toString();
}
/**
* Determines if two bags are equal.
* @param other Another object to check this bag against.
* @return True if other is an LinkedBag containing the same objects, with
* the same frequencies, as this bag.
*/
@Override
public boolean equals(Object other) {
//TODO
return false;
}
/**
* Removes all duplicates of a specific entry from this bag, leaving only
* one instance of it.
* @param anEntry the entry whose duplicates should be removed
*/
@Override
public void removeDuplicatesOf(E anEntry) {
//TODO
}
/**
* Removes all duplicate items from this bag, leaving one instance of each
* entry.
*/
@Override
public void removeAllDuplicates() {
//TODO
}
}