grokcore.annotation 3.0.1 on PyPI

This package provides a support to simplify the use of annotations in Zope.

Contents

Setting up grokcore.annotation
Example
API Overview
- Base classes

Setting up `grokcore.annotation`

This package is essentially set up like the grokcore.component package, please refer to its documentation for details. The only additional ZCML line you will need is:

<include package="grokcore.annotation" />

Put this somewhere near the top of your root ZCML file but below the line where you include grokcore.component's configuration.

Example

Here a simple example of use of an annotation:

import grokcore.annotation
from zope import interface

# Create a model and an interface you want to adapt it to
# and an annotation class to implement the persistent adapter.
class Mammoth(grokcore.annotation.Model):
    pass

class ISerialBrand(interface.Interface):
    unique = interface.Attribute("Brands")

class Branding(grokcore.annotation.Annotation):
    grokcore.annotation.implements(ISerialBrand)
    unique = 0

# Grok the above code, then create some mammoths
manfred = Mammoth()
mumbles = Mammoth()

# creating Annotations work just like Adapters
livestock1 = ISerialBrand(manfred)
livestock2 = ISerialBrand(mumbles)

# except you can store data in them, this data will transparently persist
# in the database for as long as the object exists
livestock1.unique = 101
livestock2.unique = 102

# attributes not listed in the interface will also be persisted
# on the annotation
livestock2.foo = "something"

API Overview

Base classes

Annotation: Base class for an Annotation. Inherits from the persistent.Persistent class.
Model: Base class for a Model on which you want to use an annotation.
queryAnnotation(model, interface): Query the annotation on the given model for the given interface. Return the annotation if found, None otherwise. This will not make any write operation.
deleteAnnotation(model, interface): Look for the given annotation and delete it from the model.
LazyAnnotation: Base class for an annotation. It only writes a database object when explicitly setting values on the lazy properties.
LazyAnnotationProperty: Property implementation that works with LazyAnnotation.