1. Abstraction A tool (concept) to manage complexity
Hide irrelevant details; focus on the features needed
Examples
Integer addition
File deletion using icons
The brakes on a car
Television remotes
Primitive date types are already abstracted from bits 0/1
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2. Some here are primitive data types
Characterize data into different kinds for convenience
Some here are primitive data types
bit
byte
integer
ascii
character
array
string
real
record
objects
+ operations
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3. Data Type (how to view it)
Specification View of a data type
Data values
Operations defined on those values
Abstract Data Type (ADT) –use of abstraction!
Implementation View of a data type
Language-specific representation for the values
Implementation of the operations
 Implementation of an ADT
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4. Abstract model of Priority Queues
Abstract Data Type (ADT)
Abstract model of Priority Queues
(Specification View)
insert one
item
Priority Queue
Get the one with the highest priority
the minimum one
(or maximum)
a black box
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5. Abstract model of Priority Queues (Implementation View)
Abstract Data Type (ADT)
Abstract model of Priority Queues
(Implementation View)
insert one
item
Binary Search Tree or
Binary Heap?
Get the one with the highest priority
the minimum one
(or maximum)
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6. Collection is an ADT Typical Operations Add an element
Remove an element
Replace an element
Retrieve an element
Determine if a collection contains an element
Get the collection’s size
Determine if a collection is empty
Traverse a collection
Determine if two collections are equal
Clone a collection
Serialize a collection
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7. List is a Collection with extra two requirements
Homogenous
Logical Order
Student 1, Student 2, Student 3, Student 4
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8. At the implementation level: Tow kinds of Lists
student 1
student 2
student 3
student 4
Linked List
student 4
student 1
student 3
student 2
Array
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9. Array Characteristics
student 1
student 2
student 3
student 4
The elements of an array are in adjacent memory locations
An array is a random (direct) access data structure. A
A[0]
A[1]
A[2]
A[3]
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10. The Java Collections Framework (JCF)
Queue
List
{interface}
{interface}
{interface}
RandomAccess
AbstractList
{marker interface}
{abstract}
The Java Collections Framework (JCF)
UML Class Diagram
ArrayList
Vector
AbstractSequentialList
{abstract}
Java Provides a List interface for several implementations
Stack
LinkedList
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11. Some typical operations on Lists
What can be done?
What can be easily done?
Some typical operations on Lists
Array
Linked List
student 1
student 2
student 3
student 4
student 4
student 1
student 3
Random access
Add/remove from the head
Add/remove from the tail
Add/remove from the middle
Resize
student 2
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IT 179