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Dequeue Interface → Dequeue in Java

Dequeue Interface

Dequeue in Java

Deque Interface in Java Collections The Deque (pronounced "deck") interface in Java's Collections Framework extends the Queue interface and offers functionalities beyond a standard queue. It provides a richer data structure, acting as a double-ended queue. This means elements can be inserted and removed from both the front and the back of the collection.

Features

⯄ Double-Ended Operations: Unlike a standard queue (FIFO - First-In-First-Out), Deque allows adding and removing elements from both ends: ⯄ Front: The beginning of the deque (equivalent to the head in a queue). ⯄ Back: The end of the deque (equivalent to the tail in a queue). ⯄ Extends Queue: Deque inherits all methods from the Queue interface, providing functionalities like peek (retrieve the first element without removal) and isEmpty (check if the deque is empty). ⯄ Additional Methods: Deque provides specific methods for operating from both ends: ⯄ Adding: addFirst(element), addLast(element) ⯄ Removing: removeFirst(), removeLast() ⯄ Peeking: peekFirst(), peekLast()

Common Implementations

⯄ ArrayDeque: This is a resizable array-based implementation that offers efficient random access but might have overhead for frequent insertions/removals at the beginning. ⯄ LinkedList: This is a linked list-based implementation that excels in adding/removing from both ends but has slower random access compared to ArrayDeque. Benefits ⯄ Undo/Redo Functionality: Implement a stack-like behavior by adding/removing elements from the front for "undo" and from the back for "redo". ⯄ Browsing History: Maintain a history of visited webpages where users can navigate forward and backward. ⯄ Job Queues: Manage a queue of tasks where high-priority jobs can be inserted at the front for immediate processing. Conclusion The Deque interface offers a versatile data structure for scenarios where you need to efficiently insert and remove elements from either end of the collection. It provides a powerful alternative to standard queues by enabling flexible access and manipulation from both sides.

Tutorials