da739765d8
git-svn-id: svn://svn.cy55.de/Zope3/src/cybertools/trunk@1744 fd906abe-77d9-0310-91a1-e0d9ade77398
74 lines
2.4 KiB
Text
74 lines
2.4 KiB
Text
================================================================
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Composer - Building Complex Structures with Templates or Schemas
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================================================================
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($Id$)
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>>> from cybertools.composer.base import Element, Compound, Template
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>>> from cybertools.composer.instance import Instance
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We set up a very simple demonstration system using a PC configurator.
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We start with two classes denoting a configuration and a simple
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component within this configuration.
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>>> class Configuration(Template):
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... def __init__(self, name):
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... self.name = name
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... super(Configuration, self).__init__()
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>>> class BasicComponent(Element):
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... def __init__(self, name):
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... self.name = name
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... def __repr__(self):
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... return self.name
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>>> desktop = Configuration('Desktop')
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>>> desktop.components.append(BasicComponent('case'))
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>>> desktop.components.append(BasicComponent('mainboard'))
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>>> desktop.components.append(BasicComponent('cpu'))
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>>> desktop.components.append(BasicComponent('harddisk'))
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Now somebody wants to configure a desktop PC using this configuration.
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We need another class denoting the product that will be created.
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>>> class Product(object):
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... def __init__(self, productId):
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... self.productId = productId
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... self.parts = {}
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... def __repr__(self):
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... return self.productId
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>>> c001 = Product('c001')
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The real stuff will be done by an instance adpater that connects the product
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with the template.
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>>> class ConfigurationAdapter(Instance):
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... def applyTemplate(self):
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... for c in self.template.components:
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... print c, self.context.parts.get(c.name, '-')
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>>> inst = ConfigurationAdapter(c001)
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>>> inst.template = desktop
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>>> inst.applyTemplate()
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case -
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mainboard -
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cpu -
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harddisk -
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If we have configured a CPU for our configuration this will be listed.
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>>> c001.parts['cpu'] = Product('z80')
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>>> inst.applyTemplate()
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case -
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mainboard -
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cpu z80
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harddisk -
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Note that the ConfigurationInstance's applyTemplate() method is fairly
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primitive. In a real-world application there usually are a lot more methods
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that do more stuff. In our PC configurator application there might be
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methods that just list components (e.g. to provide a user interface),
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retrieve candidate products (e.g. CPUs) to use in the
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configuration and store the user's selection in the context object.
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