[Zope-Checkins] CVS: Zope2 - Adapter.py:1.1.2.1

[Jim Fulton]

Update of /cvs-repository/Zope2/lib/python/ComponentArchitecture
In directory korak.digicool.com:/tmp/cvs-serv13848

Added Files:
      Tag: NR-branch
	Adapter.py 
Log Message:
*** empty log message ***


--- Added File Adapter.py in package Zope2 ---
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"""(simple) Adapter management

If an adapter provides an output for an input:

  - It provides bases of the output for the input.

  - It provides the output (and bases of the output)
    for interfaces that extend the
    input.

"""

import Errors

class GlobalAdapterFactory:
    
    __implements__=IAdapterFactory

    def __init__(self):
        _adapters={}

    def _provideAdapter(self, input, output, adapter, boutput):
        old = self._adapters[input, boutput]
        if old is not None:
            oldoutput=old[0]
            if not old.extends[output]:
                return # The new output is not more general
        self._adapters[input, boutput]=output, adapter
        for b in boutput.__bases__:
            self._provideAdapter(input, output, adapter, b)        

    def provideAdapter(self, input, output, adapter):
        self._provideAdapters(input, output, adapter, output)

    def _getAdapter(input, output):
        marker=None
        a=_adapters.get((input, output), marker)
        if a is not marker: return a
        for input in input.__bases__:
            a=_getAdapter(input, output)
            if a is not marker: return a
        return _marker

    def getAdapterForInterfaces(inputs, output, TupleType=type(())):
        marker=None
        if type(inputs) is TupleType:
            for input in inputs:
                a=getAdapterForInterfaces(input, output)
                if a is not marker: return a
        else:
            return _getAdapter(inputs, output)

    def getAdapter(object, output, default=_marker):
        if output.implementedBy(object): return object

        a=getattr(object, '__implements__', _marker)
        if a is not _marker:
            a=getAdapterForInterfaces(a, output)
        else:
            a = _getAdapter(None, output)

        if a is _marker:
            raise Errors.AdapterNotFound(object, output)
        return a(object)


Service.defineService('AdapterFactory', IAdapterFactory)
Service.provideGlobalService("AdapterFactory", GlobalAdapterFactory())