Transcript Chapter Eight - Object-Oriented Application Frameworks

George Blank
University Lecturer
CS 602
Java and the Web
Object Oriented Software Development
Using Java
Chapter 8
Application Frameworks
• Java has an extensive collection of
application frameworks, collections of
cooperating classes that can be used in
developing applications.
• Chapter 8 emphasizes three such
frameworks—collections, input/output and
GUIs using AWT and Swing.
Expected knowledge
• Students should not only understand and be able to
use the classes described in the text, but must also
develop skill in using Java documentation to go
beyond the material in the text.
• It is recommended that students become familiar with
http://java.sun.com/reference/docs/index.html
• Another good site: http://javadocs.org/
Chapter notes
• There is so much in this chapter that I
hesitate to add more to the readings.
• I do recommend that students make certain
that they understand the topics described in
the chapter summary.
Abstract Collection Types
• A bag or multiset is an unordered collection of elements
that may include duplicates. A bag, in Java the
Collection interface, is the least restrictive and most
general form of collection.
• A set is an unordered collection of elements without
duplicates.
• A list is an ordered collection of elements.
• A map, dictionary or associative array is an unordered
collection of key-value pairs.
Methods of Interface Collection
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add(element)
addAll(collection)
clear()
contains(element)
containsAll(collection)
isEmpty()
iterator()
remove(element)
• removeAll(collection)
• retainAll(collection)
• size()
Methods of Interface List
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add(i,element)
add(element)
addAll(collection)
addAll(i,collection)
get(i)
indexOf(element)
lastIndexOf(element)
containsAll(collection)
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listIterator()
listIterator(i)
remove(i)
remove(element)
removeAll(collection)
set(i,element)
subList(i,j)
Methods of Interface Map
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clear()
containsKey(k)
containsValue(v)
entrySet()
get(k)
isEmpty()
keySet()
put(k,v)
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put(map)
remove(k)
removeAll(collection)
size()
values()
k = key
v = value
Types of Sets
• A HashSet stores elements in a hash table.
• A LinkedHashSet is an ordered hash table.
• A TreeSet stores elements in a balanced binary
tree.
Concrete Collections
Sets
• HashSet
• LinkedHashSet
• TreeSet1
Lists
• Array List
• Linked List
• Vector
Maps
• HashMap
• IndentityHashMap
• LinkedHashMap
• TreeMap1
• Hashtable
1sorted
Ordering
• An order (technically a partial order) is a
transitive binary relationship between two
objects. Organized by some criteria, if a has
a certain relationship with b and b has the
same relationship with c, then a has that
relationship with c.
• A sorted collection is one that orders its
elements by a particular relationship.
Defining Orders on Objects
• A class can define a natural order among its
instances by implementing the comparable
interface.
• Arbitrary orders among different objects can be
defined by comparators, or classes that by
implement the comparator interface.
• SortedSet and SortedMap are sorted abstract
collections that inherit the functions of sets and
maps respectively.
Word Frequency example
• The Class WordFrequency2 on pages 327-328
shows an example of using a sorted map sorted
by their natural keys. It first orders the words in a
piece of text and then counts the identical words to
determine their frequency. Class WordFrequency4
on page 332 extends this to sort the result and
display the words in frequency order.
Java Graphical User Interfaces
• Java has a GUI framework consisting of several categories
of classes:
• GUI Components (widgets) have a characteristic
appearance (look) and behavior (feel).
• Layout managers package components in windows. (see
FlowLayout and BorderLayout)
• Events and Event Listeners
• Grapics and Imaging classes
Abstract Windows Toolkit
• The basic Java GUI toolkit is the Abstract Windows
Toolkit (AWT) The Swing package is an extension of
AWT to build high quality GUIs.
• Review the hierarchy of awt at
http://java.sun.com/j2se/1.5.0/docs/api/java/awt/package-tree.html to see
the wde variety of classes available to build GUI
applications.
• The Java Class hierarchy is a good starting place to
understand Java libraries:
http://java.sun.com/j2se/1.5.0/docs/api/overview-tree.html
Understanding Layouts
• It is important to practice using the layouts
such a flow layouts in order to understand
how to present information attractively to the
end user. Problem 8.5 in the text is a good
exercise for this purpose.
Bibliography
• Jia, Xiaoping, Object Oriented Software
Development Using Java. Addison Wesley,
2003
• http://java.sun.com/reference/docs/index.html
• http://javadocs.org/