Download CollabCAD and Jython Scripting Presentation

CollabCAD Jython & Swing
TM
Embedding Jython
Interpreter … Scripting
Support
G. Prasad, CAD Group, NIC
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Agenda
Overview of Jython
Using Swing in Jython
Jython and CollabCAD
ScriptingInterface
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Python
A very high-level, object-oriented,
open-source programming language
“Pseudo-code that runs”
Tutorial and documentation at:
http://www.python.org
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Jython
Implementation of Python in Java
(originally Jpython)
http://www.jython.org
Ease of Python, plus seamless access to
every Java class libraries
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Overview of Jython
Interpreted (No compilation)
 Dynamic (run-time) strong typing

– No need to declare variables(no explicit
static typing), determined at runtime
Modules, classes, functions
 Built-in types: tuples, lists,
dictionaries

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Jython Syntax
ibm04:/home/gpr/jython-2.1:[32]jython
Jython 2.1 on java1.4.2 (JIT: null)
Type "copyright", "credits" or "license" for more
information.
>>>
Whitespace is used to delimit blocks
for i in range(5):
if i < 2:
print i
print “Done”
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Jython Conditional Logic
if expression:
block
elif expression:
block
else:
block
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Jython boolean logic
Generally….
Non-zero is true, 0 is false
Objects are true, None* is false
Empty lists are false
use: and, or, not
* None is the equivalent of Null
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Jython Loops
while expression:
block
else:
block
# exits once on normal
# loop end
Note: pass, break, continue
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Jython Loops
For variable in sequence:
block
else:
block
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Jython Loops
for x in (‘a’, 5, [1, 2]):
print x
for x in range(10):
print x
# prints 0, 1, 2, …, 9
for key, value in dict.items():
print key, “ : ” , value
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Jython Lists
Heterogeneous, mutable
list(sequence)
l = [1, ‘test’, [9,
len(l)
l[1] = ‘foo’
l.remove(5)
l.append(2)
newList = l[2:4]
10], 5]
#4
# [1, ‘foo’, [9, 10], 5]
# [1, ‘foo’, [9, 10]]
# [1, ‘foo’, [9, 10], 2]
# [[9, 10], 2]
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Jython Strings
s1 = ‘This is a string.’
s2 = “So is this.”
s3 = s1 + ‘ ‘ + s2
s2.split()
# [‘So’, ‘is’, ‘this.’]
s2.find(‘is’)
#3
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Jython Tuples
Heterogeneous, immutable: accepts one
argument that must be a sequence and returns a
tuple with the same members as those in the
argument
tuple(sequence)
t = (‘example’, 1, [1, 2])
len(t)
#3
t[1]
#1
t[1] = 3
# TypeError
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Jython Dictionaries
(Key, value) pairs, similar to hash tables
dict = {‘one’: 1, 2 : ‘two’ }
dict.keys()
# [‘one’, 2]
dict.values()
# [1, ‘two’]
dict[3] = 4
dict.items()
# [(‘one’, 1),
# (2, ‘two’), (3, 4)]
del dict[3]
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Jython Exception Handling
try:
block
except: / except exception-type:
block
else:
block # if no exceptions raised
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Jython Exception Handling
try:
block
finally:
block
# executed even if exception
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Jython Functions
def FuncName(args):
block
def AddNumbers(a , b):
return a + b
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Jython Functions
Keyword arguments and default values
def AddSome(a, b=9, c=10):
return a + b + c
AddSome(1, 2, 3)
AddSome(1, 2)
AddSome(1)
#6
# 13
# 20
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Jython Classes
class MyClass:
def __init__(self, aValue = 5):
self.aField = aValue
def addToField(self, aNumber)
self.aField += aNumber
def printField(self):
print self.aField
inst1 = MyClass()
inst2 = MyClass(10)
inst1.aField = 6
inst1.addToField(1)
inst1.printField()
MyClass.printField(inst2)
#7
# 10
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Jython Classes: Inheriting
class MyNewClass(MyClass):
def __init__(self):
MyClass.__init__(self, 8)
inst = MyNewClass()
inst.aField
#8
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Jython: Prototype-Instance
inst = MyClass()
inst.b = ‘test’
inst.b
# test
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Jython Modules
Basic unit for managing namespace
Usually a file full of code (.class, .jar, .py)
import javax.swing
import javax.swing as swing
from javax.swing import JFrame
from javax.swing import *
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Swing
Essentially a library of classes for
building GUIs
Part of the Java Foundation Classes
Online tutorial:
http://java.sun.com/docs/books/tutorial/uiswing/
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Useful Swing Classes
JFrame (essentially a window)
JLabel
JButton
JTextField
JTextArea
JMenuBar
JScrollPane
JPanel
JPasswordField
JTable
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Jython and Swing
Can work with Java classes from within Jython
import javax.swing as swing
frame = swing.JFrame(‘Hello World Swing’)
frame.setDefaultCloseOperation(
swing.JFrame.EXIT_ON_CLOSE)
label = swing.JLabel(“Hello World”)
frame.getContentPane().add(label)
frame.pack()
frame.setVisible(1)
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Jython, Swing, and Listeners
Jython also handles Listener wrapping for you
Instead of:
int count = 1;
JButton button = new JButton(“Increment”);
button.addActionListener(
new ActionListener{
public void actionPerformed(ActionEvent e) {
count++;
})
Use:
count = 1
def Increment(event):
count += 1
button = swing.JButton(“Increment”, actionPerformed = Increment)
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Learning More
Python and Jython websites
 Jython for Java Programmers

– Robert W Bill (NewRiders)

Jython Essentials
– S.Pedroni and N.Rappin(O’Reilly)
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CollabCAD and Jython
CollabCAD
- http://www.collabcad.com/
Jython Interpreter
- ScriptingInterface (see User’s
guide)
- Tools  Execute Script
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ScriptingInterface
Embed a Jython interpreter directly into
Java code. An instance of the interpreter
can be used within a Java program to
evaluate Jython code.
 Easy to use methods available to interact
with CollabCAD
 Allows Jython scripts to
create/edit/modify CollabCAD entities.

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Jython Console Frame in CollabCAD
Jython Console Frame
An
independent
Jython Console Frame is
invoked where a user can
interactively
enter
Jython expressions as
well
as
use
the
CollabCAD
scripting
methods.
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Jython Console Panel in CollabCAD
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Example Jython script for CollabCAD
TM
import incad.Incad as incad
theApp =
incad.getScriptingInstance()
import javax.vecmath.Point3d as
P3d
p1 = P3d(100,100,-50)
p2 = P3d(200,200,55)
box1 = theApp.addBox(p1,p2)
p4 =
0.0)
p5 =
0.0)
p6 =
22.0,
ar2 =
theApp.addPoint(104.0, 22.0,
theApp.addPoint(126.0, 0.0,
theApp.addPoint(104.0, 0.0)
theApp.addArc(p4, p5, p6)
Import Incad class and refer to it using
the identifier incad in the script
Create an instance of Incad to expose
its methods
Import Point3d class ( Java3D object)
Create two Point3d objects
Create a CollabCAD SolidBox entity by
calling the method using two corner
points
Create three points for creating a
CollabCAD CADArc
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Jython Interactive session
Starting Jython in an interactive mode
ibm04:/home/gpr/jython-2.1:[49]jython
Jython 2.1 on java1.4.2 (JIT: null)
Type "copyright", "credits" or "license" for more information.
>>>
You
>>>
>>>
>>>
>>>
>>>
can type any Jython code and see the result. Type in some Swing GUICode
import javax.swing as swing
win = swing.Jframe(“Welcome to Jython”)
// create a window object
win.size = (200,200)
// size of the window
win.show()
// get the window on the screen
field = swing.JTextField(preferredSize=(200,200))// add a textfield object to the
window
>>> win.contentPane.add(field)
>>> win.pack()
>>> win.show()
>>> field.text
‘It is Jython’
You can add buttons,etc and also behaviour to it.
Running this script from Jython ( executing jython filename at an ordinary command prompt) will
give the same window and behaviour.
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THANK YOU
Q&A
Thanks for your time
Any queries : [email protected]
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