Class RecentlyViewedQueue

java.lang.Object

java.util.AbstractCollection<SearchedItemPanel>

java.util.AbstractQueue<SearchedItemPanel>

java.util.concurrent.ArrayBlockingQueue<SearchedItemPanel>

org.troy.capstone.data_structures.RecentlyViewedQueue

All Implemented Interfaces:

Serializable, Iterable<SearchedItemPanel>, Collection<SearchedItemPanel>, BlockingQueue<SearchedItemPanel>, Queue<SearchedItemPanel>

public class RecentlyViewedQueue
extends ArrayBlockingQueue<SearchedItemPanel>

RecentlyViewedQueue is a queue to manage recently viewed items, with a fixed capacity. Oldest item is removed when capacity is exceeded. Does not allow duplicates.

See Also:

• Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
private static final int	CAPACITY	Capacity of the recently viewed queue, set to 10 for a reasonable number of items to display without overwhelming the user.
private final ArrayBlockingQueue<String>	itemIds	Queue to keep track of item IDs for quick lookup and to prevent duplicates.
private final ItemRepo	itemRepo	Repository to retrieve item details based on item IDs, used to create SearchedItemPanel instances when adding items to the queue.

Constructor Summary

Constructors

Constructor	Description
RecentlyViewedQueue(ItemRepo itemRepo)	Constructor for the RecentlyViewedQueue.

Method Summary

Modifier and Type	Method	Description
private void	add(String itemId)	Adds an item to the RecentlyViewedQueue without checking for duplicates or capacity.
void	addAttempt(String itemId)	Attempts to add an item to the RecentlyViewedQueue.
List<SearchedItemPanel>	peekAll()	Returns a List containing all items in the queue in reverse order, without removing them.

Methods inherited from class ArrayBlockingQueue

add, clear, contains, drainTo, drainTo, forEach, iterator, offer, offer, peek, poll, poll, put, remainingCapacity, remove, removeAll, removeIf, retainAll, size, spliterator, take, toArray, toArray, toString

Methods inherited from class AbstractQueue

addAll, element, remove

Methods inherited from class AbstractCollection

containsAll, isEmpty

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface Collection

addAll, containsAll, equals, hashCode, isEmpty, parallelStream, stream, toArray

Methods inherited from interface Queue

element, remove

Field Details

CAPACITY

private static final int CAPACITY

Capacity of the recently viewed queue, set to 10 for a reasonable number of items to display without overwhelming the user.

See Also:

• Constant Field Values

itemRepo

private final ItemRepo itemRepo

Repository to retrieve item details based on item IDs, used to create SearchedItemPanel instances when adding items to the queue.

itemIds

private final ArrayBlockingQueue<String> itemIds

Queue to keep track of item IDs for quick lookup and to prevent duplicates. Faster than using SearchedItemPanel directly since a lot of work is done to create a panel before checking.

Constructor Details

RecentlyViewedQueue

public RecentlyViewedQueue(ItemRepo itemRepo)

Constructor for the RecentlyViewedQueue.

Parameters:

itemRepo - The ItemRepo to use for retrieving item details.

Method Details

addAttempt

public void addAttempt(String itemId)

Attempts to add an item to the RecentlyViewedQueue.

Parameters:

itemId - The ID of the item to add.

Preconditions:

itemId is not null and corresponds to a valid key in the ItemHashMap.

Postconditions:

If the item is not already in the queue, it is added and the oldest item is removed. If the item is already in the queue, it is moved to the top (most recent position) without duplication. If the queue is full, the oldest item is removed to make space for the new item.

add

private void add(String itemId)

Adds an item to the RecentlyViewedQueue without checking for duplicates or capacity. Should only be called from addAttempt after those checks have been made.

Parameters:

itemId - The ID of the item to add.

Preconditions:

itemId is not null and is the key of an item allowed in the queue based on checks in addAttempt.

Postconditions:

The item with the given ID is added to the queue as a SearchedItemPanel.

peekAll

public List<SearchedItemPanel> peekAll()

Returns a List containing all items in the queue in reverse order, without removing them.

Returns:

A List of SearchedItemPanel objects representing the items in the queue, in order from newest to oldest.