Download Jython An introduction by Thinh Le

Jython
An introduction
by Thinh Le
precursor_Python
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Google App Engine
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Dropbox
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PyGTK (Gnome)
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Vim (embedded)
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BitTorrent/Morpheus
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Civilization/Battlefield
Jython
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Interpretation of Python (1997)
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Jim Hugunin & Frank Wierzbicki
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Python written in C
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Rewrite in Java
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Runs on JVM
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Interpreted Language
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Object-Oriented
Scripting Language
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Easy to learn and code
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Expressive
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Minimal structure (less lines of code)
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Does not require compilation
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Supports functional programming
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Runs external programs
Hello World
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print Hello, world!
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does not need to be enclosed in class or func
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Jython does it behind the scenes
File I/O
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file = open( fileName.txt , r )
for line in file.readlines():
print line
file.close()
Event Handling
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from javax.swing import *
def hello(event):
print Hello, world!
frame = JFrame( Hello There )
button = JButton( Hello , actionPerformed = hello)
frame.add(button)
Method Overloading
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from java.lang import Float, Double
foo(Float(9.5))
foo(Double(9.5))
Classes
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class Hello:
def _init_(self, name= John Smith ):
self.name = name
def greeting(self):
print Hello, %s % self.name
jane = Hello( Jane Smith )
joe = Hello( Joe )
default = Hello()
jane.greeting()
joe.greeting()
default.greeting()
Advantages/Disadvantages
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Readability
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Increase programmer efficiency
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Code is dynamically converted to Java byte code
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eliminate performance issues
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Cross-platform compatible
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Slow
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cannot detect undefined variable (caught at
runtime)
Implementation
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IBM WebSphere (App server)
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IBM Rational (SDLC)
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WebLogic Server
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Sikuli Demo
Questions?
Objective-C
• 
An introduction
• 
by Thinh Le
Objective-C
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Developed in the 1980s by Stepstone
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Superset of C
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Any C program compilable as Obj-C
Object syntax derived from Smalltalk
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Dynamic typing, message based
Objective-C 2.0
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Introduced with Mac OS 10.5
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Only supports runtime systems
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GNUStep, Cocoa, Cocoa Touch
Supports garbage collectors, properties,
dot notations, fast enumerations
iOS devices (iPhone, iPad)
Classes / Types
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Class (methods, instance variables)
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Inheritance (can have super class)
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No single root class like Java
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Object Types:
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id, nil, self ( this in Java), super
All C-Types can be used (int, float, short)
Methods / Messaging
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Methods on object called via messaging
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Sends msg w/message name to receiver
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Msg can have return value (0 or nil)
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Nested messagess: [[receiver msg1] msg2]
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Parameters: [rectangle setX: 5 y: 10]
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Dot Syntax: rectangle.width = 15;
Memory / Protocols
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Objects created are allocated memory
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Must be released when scope ends
Protocols similar to Java interfaces
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List of methods independent from class
Protocol - Example
Exception Handling
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Similar to Java
@throw myException
@try {
}@catch (NSException *e) {
NSLog(@ Caught %@: %@ , [exception name],
[exception reason]);
}
@finally{ }
Hello World
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#import <stdio.h>
int main (int argc, const char *argv[])
{
printf ( hello world\n );
return 0;
}
DEMO
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http://ideone.com
GO
• 
An introduction
• 
by Thinh Le
What is Go?
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Experimental
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Tools & packages still in development
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Concurrent and Garbage-collected
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Systems programming (compilers, web server)
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Created by Robert Griesemer, Ken Thompson,
Rob Pike of Google (2009)
Purpose of Creation
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Resource demands by applications
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Bigger libraries
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More dependencies
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Growth of clusters in Client/Server systems
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Main stream multi-core processors
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Internet and networking becoming pervasive
Goals of Go
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Efficiency and ease of use
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Performance within 10-20% of C
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Type safe and Memory safe
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Concurrency ( http://langalot.com/ )
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Garbage Collected
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High-Speed Builds
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Fast compilation & linking
Example
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package main
import fmt
//package for Printf func
func main() {
//functions have func
keyword
fmt.Printf( Hello World! )
}
Loop
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func main() {
sum := 1
i := 1
for i <= 5 {
sum += i;
i++
}
fmt.Printf( Sum is %d , sum)
}
for loop is only loop supported in Go
Functions as Objects
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func for_all(arr []int, foo func(int)) {
for i := 0; i<len(arr); i++ {
foo(arr[i]) }
}
func print(i int) {fmt.Printf( %d , i) }
func main() {
for_all([] int {1,2,3}, print);
}
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Similar to functional language. ie. Closjure
Structures
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type Point struct {
x, y int
}
func main() {
p := Point {10, 20}
fmt.Printf( p value is = %v , p)
}
Methods
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type Point struct {
x, y int
}
func (p Point) Print() {
fmt.Printf(“p value is = %v”, p)
}
func main() {
p := Point {10, 20}
fmt.Print()
}
Demo
!
http://ideone.com