Section 15. (Java Collection Framework) Udemy - Java Programming Masterclass

• Java Collections
  • Overview
  • What’s in the framework, what’s not?
  • Collection is the root of the collection hierarchy
  • Collection interface methods
  • What’s a Collection Class?
• Collection Types
  • List
  • Queue
  • Set
  • SortedSet
  • Map
  • Deque
• Collection Helper methods
  • Collections.nCopies(int count, Object o)

Java Collections

Overview

• just an object that represents a group of objects where there is some relationship for them
• arrays, lists, vectors, sets, queues, tables, dictionaries and maps
• They are differentiated by the way the store the objects in memory, how they are accesses and ordered, and whether they allow duplicates and null value s

What’s in the framework, what’s not?

• Objects who implement they Collection interface
  • except: maps

Collection is the root of the collection hierarchy

• Everything branches off of the Collection interface
• 

Collection interface methods

• 

What’s a Collection Class?

• The Collections class is not the Collections Framework

Collection Types

List

• Ordered
• aka sequence

Queue

• Ordered
• Special methods for the first & last elements
• FIFO / LIFO
• Stack and Queues

Set

• Unordered
• No Duplicates

SortedSet

• Ordered
• No Duplicates

Map

• Stores key,value pairs

Deque

Collection Helper methods

Collections.nCopies(int count, Object o)

• Similiar to Arrays.fill()
• Collections has Collections.fill() but it doesn’t work

List<Card> king_of_clubs = Collections.nCopies(2, Card.getFaceCard(Card.Suit.CLUB, 'K'));