1. CSE 1020: The Collection Framework
Mark Shtern

2. Summary
Inheritance

3. Main Interfaces List Set Map Sequence Duplicate are allowed
Duplicate are not allowed
Order is insignificant
Map
Mapping between set of keys and set of values
Mapping must be a function

4. Storage Techniques
Hash
Array
Tree
Linked

5. Implementing Classes List  ArrayList, LinkedList
Set  HashSet, TreeSet
Map  HashMap, TreeMap

6. Default
List  ArrayList
Set  HashSet
Map  HashMap

7. Example
output.println(“Enter the elements pressing Enter “); output.println(“after each. [Empty line = sentinel]”); for (String in = input.nextLine(); in.length() !=0; in = input.nextLine()) { if (!bag.add(in)) { output.println(“Not added (already present)”); }

8. Generics
List bag = new ArrayList(); bag.add(“testing”); List <Date> bag = new ArrayList<Date>(); <? extends P> or <? super C>

9. API Highlights Adding elements Removing elements boolean ddd (E o)
V put (K key, V value)
add (int index, E element)
Removing elements
boolean remove (Object o)
E remove (int index)
V remove (K key)

10. API Highlights Accessing Elements Searching E get(int index)
V get(K key)
Searching
contains(E o)
conatinsKey(K key)

11. Iteration
for(String x: bag.keySet()) { .... } for(String x: bag)

12. Searching and Sorting Collections sort (List<T> list)
binarySearch(List<? Extends T> list, T x)

13. Detection Duplicate
Problem: Given a list of integers, determine whether its element are distinct
List
Approach 1
Approach 2
Set

14. Word Frequency How do you extract words from a sentence?
Map  word and its counter

15. Sorting Map
TreeMap keeps the elements sorted on the keys