c0c772ff30
git-svn-id: svn://svn.cy55.de/Zope3/src/cybertools/trunk@1933 fd906abe-77d9-0310-91a1-e0d9ade77398
99 lines
2.6 KiB
Text
99 lines
2.6 KiB
Text
================
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Stateful Objects
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================
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($Id$)
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>>> from cybertools.stateful.definition import StatesDefinition
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>>> from cybertools.stateful.definition import State, Transition
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>>> from cybertools.stateful.definition import registerStatesDefinition
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>>> from cybertools.stateful.base import Stateful
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We start with a simple demonstration class that provides stateful
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behaviour directly.
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>>> class Demo(Stateful):
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... pass
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>>> demo = Demo()
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The default states definition has the `started` state has its initial
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state.
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>>> demo.getState()
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'started'
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>>> demo.getStateObject().title
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'Started'
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We can now execute the `finish` Transition.
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>>> demo.doTransition('finish')
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>>> demo.getState()
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'finished'
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More complex states definitions
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-------------------------------
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>>> registerStatesDefinition(
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... StatesDefinition('publishing',
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... State('private', 'private', ('show',)),
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... State('visible', 'visible', ('publish', 'hide',)),
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... State('published', 'published', ('retract',)),
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... Transition('show', 'show', 'visible'),
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... Transition('hide', 'hide', 'private'),
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... Transition('publish', 'publish', 'published'),
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... Transition('retract', 'retract', 'visible'),
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... initialState='visible'))
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>>> demo = Demo()
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>>> demo.statesDefinition = 'publishing'
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>>> demo.getState()
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'visible'
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If we try to execute a transition that is not an outgoing transition
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of the current state we get an error.
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>>> demo.doTransition('retract')
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Traceback (most recent call last):
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...
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ValueError: Transition 'retract' is not reachable from state 'visible'.
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>>> demo.getState()
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'visible'
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Stateful Adapters
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=================
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Objects that show stateful behaviour need not be derived from the Stateful
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class, for persistent objects one can also provide a stateful adapter.
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>>> from persistent import Persistent
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>>> class Demo(Persistent):
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... pass
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>>> demo = Demo()
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>>> from zope import component
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>>> from cybertools.stateful.base import StatefulAdapter
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>>> component.provideAdapter(StatefulAdapter)
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We can now retrieve a stateful adapter using the IStateful interface.
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>>> from cybertools.stateful.interfaces import IStateful
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>>> statefulDemo = IStateful(demo)
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>>> statefulDemo.getState()
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'started'
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>>> statefulDemo.getStateObject().title
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'Started'
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>>> statefulDemo.doTransition('finish')
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>>> statefulDemo.getState()
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'finished'
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If we make a new adapter for the same persistent object we get
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back the state that is stored with the object.
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>>> statefulDemo = IStateful(demo)
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>>> statefulDemo.getState()
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'finished'
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