Priority Queue

Write a Java class called Game to represent a video game. The Game object should have three instance variables: two String objects named name and console, and a Date object named date. These instance variables are to have private access modifiers. You will need to write the appropriate getter and setter methods to allow another class or object to access and modify the data values. Game should have a parameterized constructor which takes a String parameter: aName, a Date parameter: aDate, and a String parameter: aConsole (in that order). In accordance with good programming practice, you are to override the toString method inherited from Object. The toString method should return in the following format:

Name-delim-Date-delim-Console

When using the date instance variable in the toString method, use Dates getTime() method to get dates value.

Write a Java class called Lab5. Lab5 has no instance variables and contains only a single method: sortGames which reads an input file containing text. Use a Scanner object to read the contents of the input file. sortGames takes a File parameter: anInFile, a File parameter: anOutFile, and a SortBy parameter: aSort (in that order). (When importing the Date class, make sure to import java.util.Date)The given text file will contain game information, where each line of the file contains the information for a single game. The properties of each game will be separated by a specific string of characters -delim-. For example, a line of text would look like:

Final Fantasy XI: Rise of the Zilart-delim-1073000981498-delim-PS2

Where the first part of the String is the name of the game, the second the date the game was released, and the third the console the game was released for.

The sortGames method should read the contents of anInFile line by line, making each line into Game object. It should then create a PQEntry object where the value is the created Game object and the key is one of the Game objects instance variables. The created PQEntry object should then be placed in a Priority Queue object. To make a line of text into a Game object, utilize the following two methods:

split, which is a method in the String class. split takes a single String parameter and splits the String object from which it was called into a String array, using the given String parameter to determine where to break apart the host String

The Date constructor, which takes a long variable and creates a date which represents the number of milliseconds since the standard base time known as "the epoch", namely January 1, 1970, 00:00:00 GMT.

After parsing the entire input file, use a PrintWriter object to write the String value of each Game object in the Priority Queue to anOutFile.

Lastly, SortBy is an enumerated type. An enumerated type is a special data type that enables for a variable to be a set of predefined constants. The variable must be equal to one of the values that have been predefined for it. The SortBy enumerated type contains three values: NAME,DATE,CONSOLE. A variable of type SortBy can only be one of those three values. To define a new enumerated type variable, use:

SortBy toSort = SortBy.NAME;

To compare enumerated types, use the == operator. For example:

if(toSort == SortBy.NAME){}

would evaluate to true. In sortGames, use the given enumerated type to determine which of Games instance variables should be the Key used for PQEntry. If toSort is equal to SortBy.NAME, then when creating a PQEntry object, the key should be the Game objects name instance variable and the value should be the Game object itself.

NOTE: To implement this method, you may find yourself defining a Priority Queue before initializing it. Because you may initialize the defined Priority Queue with different data types depending on the value of the SortBy parameter, you wont be able to specify the data types of the Priority Queue when you define it. This will cause a compiler warning which we can safely ignore.

NOTE TWO: You will need to create Comparator objects to be used when initializing new priority queues. Use the Comparator classes on Blackboard as templates.

_________ PQEntry.java _________

package providedClasses; public class PQEntry implements Entry{ private K key; private V value; public PQEntry(K aKey, V aValue) { key = aKey; value = aValue; } @Override public K getKey() { return key; } @Override public V getValue() { return value; } @Override public String toString() { return "K: " + key.toString() + " V: " + value.toString(); } } ______ Priorityqueue.java ______ 

package providedClasses; import java.util.Comparator; public class PriorityQueue { Queue> queue; Comparator comparator; public PriorityQueue(Comparator aComparator) { queue = new Queue>(); comparator = aComparator; } public void insert(PQEntry anEntry) { if(queue.size() == 0) { queue.enqueue(anEntry); } else { boolean isAdded = false; for(int i = queue.size(); i > 0; i--) { PQEntry tempEntry = queue.dequeue(); //If tempEntry key > anEntry key --> evaluates to true if(comparator.compare(tempEntry.getKey(), anEntry.getKey()) > 0 && isAdded == false) { queue.enqueue(anEntry); queue.enqueue(tempEntry); isAdded = true; } else { queue.enqueue(tempEntry); } } if(isAdded == false) { queue.enqueue(anEntry); } } } public PQEntry remove(){ return queue.dequeue(); } public PQEntry min(){ return queue.first(); } public int size() { return queue.size(); } public boolean isEmpty() { return queue.isEmpty(); } public String toString() { return queue.toString(); } //First In First Out FIFO public class Queue { private SinglyLinkedList linkedList; public Queue() { linkedList = new SinglyLinkedList(); } public int size() { return linkedList.getSize(); } public boolean isEmpty() { return linkedList.isEmpty(); } public E first() { if(isEmpty() == true) { return null; } else { return linkedList.getFirst(); } } public E dequeue() { if(isEmpty() == true) { return null; } else { return linkedList.removeFirst(); } } public void enqueue(E anElement) { linkedList.addLast(anElement); } public String toString() { return linkedList.toString(); } @SuppressWarnings("hiding") public class SinglyLinkedList { //Instance Variables private Node head; private Node tail; private int size; //Default Constructor public SinglyLinkedList() { size = 0; } //Getter methods public int getSize() { return size; } public boolean isEmpty() { boolean toReturn = false; if(size == 0) { toReturn = true; } return toReturn; } public E getFirst() { if(isEmpty() == true) { return null; } else { return head.getElement(); } } public E getLast() { if(isEmpty() == true) { return null; } else { return tail.getElement(); } } public String toString() { String result = ""; Node aNode = head; if(aNode != null) { result = aNode.toString() + " , " + result; while(aNode.getNextNode() != null) { aNode = aNode.getNextNode(); result = aNode.toString() + " , " + result; } } result = "[" + result + "]"; return result; } //Setter methods public void addLast(E anElement) { //Create a new node with the given element. Because this is the last node in the linked list, we set the value of the new nodes next node //to null, as there is no next node Node newNode = new Node(anElement,null); //If the linked list is empty we make the new node the head node because it will be both the head and the tail node. if(isEmpty() == true) { head = newNode; } else { //If the linked list has nodes in it already, we link the new node to the current tail of our linked list tail.setNextNode(newNode); } //We update the tail and size instance variables tail = newNode; size++; } public E removeFirst() { if(isEmpty() == true) { return null; } else { E toReturn = head.getElement(); head = head.getNextNode(); size--; if(size == 0) { tail = head; } return toReturn; } } } public class Node { //Instance Variables private G element; private Node next; //Parameterized Constructor public Node(G anElement, Node nextNode) { element = anElement; next = nextNode; } //Getters and setters public G getElement() { return element; } public void setElement(G anElement) { element = anElement; } public Node getNextNode(){ return next; } public void setNextNode(Node nextNode) { next = nextNode; } public String toString() { return element.toString(); } } } }