1. (Java Collections Framework) AbstractSequentialList
JCF
(Java Collections Framework)
Collection
List
{interface}
{interface}
Java Provides a List interface for several implementations
RandomAccess
AbstractList
{interface}
{abstract}
ArrayList
Vector
AbstractSequentialList
{abstract}
Stack
LinkedList
11/28/2018
IT 179

2. ArrayList Method Summary
 boolean
add (E o) Appends the specified element to the end of this list.
 void
add (int index, E element) Inserts the specified element at the specified position in this list.
clear () Removes all of the elements from this list.
ensureCapacity (int minCapacity) Increases the capacity of this ArrayList instance, if necessary, to ensure that it can hold at least the number of elements specified by the minimum capacity argument.  E
get (int index) Returns the element at the specified position in this list.
 int
indexOf (Object e) Searches for the first occurrence of the given argument, testing for equality using the equals method.
isEmpty () Tests if this list has no elements.
11/28/2018
IT 179

3. ArrayList Method Summary
remove (int index) Removes the element at the specified position in this list.
 boolean
remove (Object o) Removes a single instance of the specified element from this list, if it is present (optional operation).
set (int index, E element) Replaces the element at the specified position in this list with the specified element.
 int
size () Returns the number of elements in this list.
 Object[]
toArray () Returns an array containing all of the elements in this list in the correct order.
 void
trimToSize () Trims the capacity of this ArrayList instance to be the list's current size.
11/28/2018
IT 179

4. Interface for the user ArrayList LinkedList Vector Stack XXXX List
....
Interface for the user
public int size();
public T get(int i);
public T set(int i, T item);
public int indexOf(T item);
public void add(T item);
public void add(int i, T item);
public T remove(int i);
public Object[] toArray();
public <K> K[] toArray(K[] a); 7 2 4 6 1 3 5 8
11/28/2018
IT 179

5. Interface for the user 1 [0] [1] 2 [2] 3 [3] 4 [4] 5 [5] 6 [6] 7 [7] 8
ArrayList< > 1
[0]
public int size();
public T get(int i);
public T set(int i, T item);
public int indexOf(T item);
public void add(T item);
public void add(int i, T item);
public T remove(int i);
public Object[] toArray();
public <K> K[] toArray(K[] a);
[1] 2
[2] 3
[3] 4
[4] 5
[5] 6
[6] 7
[7] 8
[8]
[9]
11/28/2018
IT 179

6. ArrayList class (generic)
import java.util.ArrayList;
.....
ArrayList<String> L = new ArrayList<String>();
L.add(“Good");
L.add(“Afternoon"); L
“Good”
“Afternoon”
11/28/2018
IT 179

7. What happen behind the scene
import java.util.ArrayList;
.....
ArrayList<String> L = new ArrayList<String>(8);
L.add(“Smith");
L.add("Robinson");
L.set(0,"Good"); …
Good L L
Smith
Smith
Robinson
Size=1
Size=2 L
Size=0
Capacity =8
Capacity =8
Capacity=8
11/28/2018
IT 179

8. L …… Good L.add(“Smith"); L.add("Robinson"); L.set(0,"Good");
L.add(1, "Mrs.");
Good
Smith
Mrs.
Robinson L !!
Size=2
Size=3
Size=4
Capacity=8
11/28/2018
IT 179

9. L …… Good L.add(“Smith"); L.add("Robinson"); L.set(0,"Good");
L.add(1, "Mrs.");
L.add(1, "Afternoon");
L.add(2, "!");
Good
Afternoon
Mrs.
Robinson L !!
Size=4
Size=5
Capacity=8
IT 179
11/28/2018

10. L …… Good L.add(“Smith"); L.add("Robinson"); L.set(0,"Good");
L.add(1, "Mrs.");
L.add(1, "Afternoon");
L.add(2, "!");
Good
Afternoon
Morning !
L.set(1, "Morning");
Mrs. L
Robinson !!
Size=6
Capacity=8
11/28/2018
11/28/2018
IT 179

11. AbstractSequentialList
The Java Collections Framework (JCF)
Collection
List
{interface}
{interface}
Java Provides a List interface for several implementations
RandomAccess
Iterable
AbstractList
{interface}
{interface}
{abstract}
ArrayList
Vector
AbstractSequentialList
{abstract}
Stack
LinkedList
11/28/2018
IT 179

12. Need for Iterators O(n) The internal information1 5
iterA 2 4 3 3 4 2 5 3
iterB 1 6 2 7 1 8
iterC
while (iter.hasNext()) {
.....
iter.next()..... }
The internal information
and structures are protected. 8 6 7 4
O(n) 1 3 2 5
11/28/2018
IT 179

13. AbstractList<T>
Iterable<T>
{interface}
+ Iterator<T> iterator();
AbstractList<T>
{interface}
(see the java document) ….
is-relation
has-relation
is-relation
Iterator<T>
{interface}
+ boolean hasNext();
+ T next();
+ void remove();
ArrayList<T>
11/28/2018
IT 179

14. API java.util.Iterator<E>
Interface (usually for
some internal class)
Iterator<E>
bool hasNext();
E next();
void remove();
import java.util.Iterator;
.....
static ArrayList<Card> pick(char suit, PokerDeck deck) {
ArrayList<Card> a = deck.toArrayList();
Iterator<Card> aiter = a.iterator();
while (aiter.hasNext()) {
if (aiter.next().getSuit() != suit)
aiter.remove(); }
return a;
11/28/2018
IT 179

15. Ace Finding Game H2 H13 H3 H4 H5 H7 H12 H10 H6 H1 H8 H9 H11
11/28/2018
IT 179