"Bobo and Principia: An Object-Based Web Application Platform"
by Amos Latteier
Web Techniques, January 1999
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the author is maintained within the comments of the source. For
questions, contact editors@web-techniques.com.
[LISTING ONE]
# Acquisition of a phone number
import Acquisition
# define empty classes that use acquisition
class Location(Acquisition.Implicit): pass
class Individual(Acquisition.Implicit): pass
# create home, work and me objects
home=Location()
home.phone="555-1212"
work=Location()
work.phone="123-4567"
me=Individual()
# locate me at home
home.resident=me
print home.resident.phone # prints "555-1212"
# locate me at work
work.worker=me
print work.worker.phone # prints "123-4567"
[LISTING TWO]
# Basic persistence and object database use
import BoboPOS
class Customer(BoboPOS.Persistent):
"A persistent class"
def __init__(self,name):
self.name=name
def set_favorite(self,food):
self.favorite_food=food
# open the object store
db=BoboPOS.PickleDictionary("customers.bbb")
# if amos is not already in the object store
if not db.has_key("amos"):
# create a Customer instance in the object store
db["amos"]=Customer("Amos")
# change an attribute of the persistent object
db["amos"].set_favorite("spam")
# commit the change
get_transaction().commit()
# prints "Amos' favorite food is spam"
print "Amos' favorite food is", db["amos"].favorite_food
[LISTING THREE]
# Templates are used to display an object in HTML
import DocumentTemplate
class Food:
"Something edible"
def __init__(self,name,calories):
self.name=name
self.calories=calories
def is_fattening(self):
if self.calories > 100:
return 1
index_html=DocumentTemplate.HTML("""\
<html>
<p>Food: <!--#var name--></p>
<p>Calories: <!--#var calories--></p>
<!--#if is_fattening-->
<p><blink>Warning: Do Not Eat!</blink></p>
<!--#/if-->
</html>""")
# create a Food object, spam
spam=Food("SPAM",250)
# display it with its template
print spam.index_html(spam)