| """Basic, in-memory implementation of the Service-Element-Feature pattern""" |
"""Basic binding tools""" |
| |
|
| from TW.API import * |
from once import Once, New, WeakBinding |
| from TW.SEF.Interfaces import * |
import meta, modules |
| from TW.SEF.Interfaces import __all__ as allInterfaces |
|
| |
|
| from types import TupleType |
from weakref import ref, WeakValueDictionary |
| from Interface import Standard |
|
| |
from peak.naming.names import toName, Syntax, CompoundName |
| |
from peak.naming.interfaces import NameNotFoundException |
| |
from peak.util.EigenData import EigenRegistry |
| |
|
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from Interface import Interface |
| |
from peak.api import config, NOT_FOUND |
| |
|
| |
|
| __all__ = [ |
__all__ = [ |
| 'Base','App','Service','TypeService','DynamicBinding','StaticBinding', |
'Component','AutoCreated','Provider','CachingProvider', |
| 'StructuralFeature', 'Field', 'Collection', 'Reference', 'Sequence', |
'bindTo', 'requireBinding', 'bindToNames', 'bindToParent', 'bindToSelf', |
| 'Classifier','PrimitiveType','Enumeration','DataType','Element' |
'getRootComponent', 'getParentComponent', 'lookupComponent', |
| |
'acquireComponent', 'globalLookup' |
| ] |
] |
| |
|
| |
|
| # We export the interfaces too, so people don't have to dig for them... |
InterfaceClass = Interface.__class__ |
| |
|
| |
|
| |
|
| __all__ += allInterfaces |
|
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|
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|
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|
| |
|
| class DynamicBindingMC(Meta.AssertInterfaces): |
|
| |
|
| def __get__(self, obj, typ=None): |
|
| if obj is None: return self |
|
| newOb = self() |
|
| newOb._setSEFparent(obj) |
|
| obj.__dict__[newOb._componentName] = newOb |
|
| return newOb |
|
| |
|
| |
|
| class DynamicBinding(object): |
|
| __metaclass__ = DynamicBindingMC |
|
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|
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|
| class Base(object): |
|
| |
|
| """Base for all S-E-F classes""" |
|
| |
|
| __metaclasses__ = Meta.AssertInterfaces, Meta.ClassInit |
def Provider(callable): |
| __implements__ = ISEF |
return lambda foundIn, forObj: callable(forObj) |
| _sefParent = None |
|
| |
|
| def getService(self,name=None): |
|
| |
|
| if name: |
def CachingProvider(callable, weak=False): |
| if not isinstance(name,TupleType): |
|
| name = tuple(name.split('.')) |
|
| |
|
| if hasattr(self,name[0]): |
def provider(foundIn, forObj): |
| o = getattr(self,name[0]) |
|
| if len(name)==1: |
fid = id(foundIn) |
| return o |
utility = provider.cache.get(fid) |
| |
|
| |
if utility is None: |
| |
utility = provider.cache[fid] = callable(foundIn) |
| |
|
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return utility |
| |
|
| |
if weak: |
| |
provider.cache = WeakValueDictionary() |
| else: |
else: |
| return o.getService(name[1:]) |
provider.cache = {} |
| |
|
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return provider |
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def getParentComponent(component): |
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|
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"""Return parent of 'component', or 'None' if root or non-component""" |
| |
|
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try: |
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gpc = component.getParentComponent |
| |
except AttributeError: |
| |
pass |
| else: |
else: |
| parent = self.getSEFparent() |
return gpc() |
| if parent is not None: |
|
| return parent.getService(name) |
|
| |
def getRootComponent(component): |
| |
|
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"""Return the root component of the tree 'component' belongs to""" |
| |
|
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next = component |
| |
|
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while next is not None: |
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component = next |
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next = getParentComponent(component) |
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|
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return component |
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|
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def globalLookup(name, component=None): |
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|
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"""Lookup 'name' in global 'InitialContext', w/'component' in environ""" |
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|
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from peak.naming.api import InitialContext |
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|
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return InitialContext(RELATIVE_TO_COMPONENT=component).lookup(name) |
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def acquireComponent(component, name): |
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|
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"""Acquire 'name' relative to 'component', w/fallback to globalLookup()""" |
| |
|
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target = component |
| |
|
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while target is not None: |
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|
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ob = getattr(target, name, NOT_FOUND) |
| |
|
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if ob is not NOT_FOUND: |
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return ob |
| |
|
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target = getParentComponent(target) |
| |
|
| else: |
else: |
| return self.getSEFparent() |
return globalLookup(name, component) |
| |
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|
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|
| def _setSEFparent(self,parent): |
|
| from weakref import ref |
|
| self.getSEFparent = ref(parent) |
|
| |
|
| def getSEFparent(self): |
|
| return None |
|
| |
|
| def _componentName(self): |
|
| return self.__class__.__name__ |
|
| |
|
| _componentName = property(_componentName) |
|
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|
| |
|
| class App(Base): |
|
| |
|
| """Application class""" |
|
| |
|
| def newElement(self,elementType,*args,**kw): |
|
| element = apply(getattr(self,elementType),args,kw) # XXX won't do dotted names |
|
| element._fData = {} |
|
| element._setSEFparent(self) |
|
| return element |
|
| |
|
| |
|
| class Service(DynamicBinding, Base): |
|
| |
|
| """Instance (as opposed to class)""" |
|
| |
|
| __implements__ = IService |
|
| |
|
| |
|
| class TypeService(Service): |
|
| |
|
| """Service that supports a (possibly abstract) class""" |
|
| |
|
| __implements__ = ITypeService |
|
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|
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|
| class StaticBinding(object): |
|
| pass |
|
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|
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ComponentNameSyntax = Syntax( |
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direction = 1, |
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separator = '/', |
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) |
| |
|
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|
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def ComponentName(nameStr): |
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return CompoundName(nameStr, ComponentNameSyntax) |
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|
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|
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_getFirstPathComponent = dict( ( |
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('', getRootComponent), |
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('.', lambda x:x), |
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('..', getParentComponent), |
| |
) ).get |
| |
|
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|
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_getNextPathComponent = dict( ( |
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('', lambda x:x), |
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('.', lambda x:x), |
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('..', getParentComponent), |
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) ).get |
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|
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|
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|
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|
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|
| |
|
| class StructuralFeature(DynamicBinding, Base): |
|
| |
|
| # XXX lowerBound = Eval("isRequired and 1 or 0") |
|
| # XXX lowerBound.copyIntoSubclasses = 1 |
|
| |
|
| isRequired = 0 # XXX SubclassDefault(0) |
|
| |
|
| upperBound = None # None means unbounded upper end |
|
| |
|
| isOrdered = 0 |
|
| isChangeable = 1 # default is to be changeable |
|
| |
|
| referencedEnd = None # and without an 'other end' |
|
| referencedType = None |
|
| |
|
| def getElement(self): |
|
| return self.getSEFparent() |
|
| |
|
| def getService(self,name=None): |
|
| return self.getSEFparent().getService(name) |
|
| |
|
| def getReferencedType(self): |
|
| return self.getService(self.referencedType) |
|
| |
|
| def _getData(self,default=()): |
|
| return self.getSEFparent()._fData.get(self._componentName,default) |
|
| |
|
| def _setData(self,value): |
|
| self.getSEFparent()._fData[self._componentName]=value |
|
| |
|
| def _delData(self): |
|
| del self.getSEFparent()._fData[self._componentName] |
|
| |
|
| def _hasData(self): |
def lookupComponent(component, name): |
| return self.getSEFparent()._fData.has_key(self._componentName) |
|
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|
| |
"""Lookup 'name' relative to 'component' |
| |
|
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'name' can be any name acceptable to the 'peak.naming' package, or an |
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Interface object. Strings and 'CompoundName' names will be interpreted |
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as paths relative to the starting component. An empty name will return |
| |
the starting component. Interfaces will be lookedup using |
| |
'component.acquireUtility()'. All other kinds of names, including URL |
| |
strings and 'CompositeName' instances, will be looked up using |
| |
'binding.globalLookup()'. |
| |
|
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Regardless of how the lookup is processed, a 'naming.NameNotFoundException' |
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will be raised if the name cannot be found. |
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|
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Component Path Syntax |
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|
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Paths are '/'-separated attribute names. Path segments of '.' and |
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'..' mean the same as they do in URLs. A leading '/' (or a |
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CompoundName beginning with an empty path segment), will be treated |
| |
as an "absolute path" relative to the component's root component. |
| |
|
| class Field(StructuralFeature): |
Paths beginning with anything other than '/', './', or '../' are |
| |
acquired, which means that the first path segment will be looked |
| |
up using 'acquireComponent()' before processing the rest of the path. |
| |
(See 'acquireComponent()' for more details.) If you do not want |
| |
a name to be acquired, simply prefix it with './' so it is relative |
| |
to the starting object. |
| |
|
| __implements__ = IValue |
All path segments after the first are interpreted as attribute names |
| |
to be looked up, beginning at the component referenced by the first |
| |
path segment. '.' and '..' are interpreted the same as for the first |
| |
path segment.""" |
| |
|
| upperBound = 1 |
if isinstance(name, InterfaceClass): |
| |
utility = component.acquireUtility(name) |
| |
if utility is None: |
| |
raise NameNotFoundException(name, resolvedObj = component) |
| |
|
| def __call__(self): |
parsedName = toName(name, ComponentName, 1) |
| """Return the value of the feature""" |
|
| return self._getData(None) |
|
| |
|
| def values(self): |
# URL's and composite names must be handled globally |
| """Return the value(s) of the feature as a sequence, even if it's a single value""" |
|
| v=self._getData(NOT_FOUND) |
|
| if v is NOT_FOUND: return () |
|
| return v, |
|
| |
|
| def clear(self): |
if not parsedName.isCompound: |
| """Unset the value of the feature (like __delattr__)""" |
return globalLookup(name, component) |
| if self._hasData(): |
|
| self._delData() |
|
| |
|
| def set(self,value): |
if not parsedName: |
| """Set the value of the feature to value""" |
# empty name refers to self |
| if self.isChangeable: |
return component |
| self._set(value) |
|
| |
parts = iter(parsedName) |
| |
|
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attr = parts.next() # first part |
| |
pc = _getFirstPathComponent(attr) |
| |
|
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if pc: |
| |
ob = pc(component) |
| else: |
else: |
| raise TypeError,("Read-only field %s" % self._componentName) |
ob = acquireComponent(component,attr) |
| |
|
| def _set(self,value): |
resolved = [] |
| self.clear() |
append = resolved.append |
| self._setData(value) |
|
| |
|
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try: |
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for attr in parts: |
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pc = _getNextPathComponent(attr) |
| |
if pc: |
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ob = pc(ob) |
| |
else: |
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ob = getattr(ob,attr) |
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append(attr) |
| |
|
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except AttributeError: |
| |
|
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raise NameNotFoundException( |
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resolvedName = ComponentName(resolved), |
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remainingName = ComponentName([attr] + [a for a in parts]), |
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resolvedObj = ob |
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) |
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|
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return ob |
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|
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class bindTo(Once): |
| |
|
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"""Automatically look up and cache a relevant component |
| |
|
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Usage:: |
| |
|
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class someClass(binding.Component): |
| |
|
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thingINeed = binding.bindTo("path/to/service") |
| |
|
| class Collection(StructuralFeature): |
getOtherThing = binding.bindTo("some/thing", weak=True) |
| |
|
| __implements__ = ICollection |
'someClass' can then refer to 'self.thingINeed' instead of |
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calling 'self.lookupComponent("path/to/service")' repeatedly. |
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It can also do 'self.getOtherThing()' to get '"some/thing"'. |
| |
(The 'weak' argument, if true, means to bind to a weak reference.) |
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""" |
| |
|
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singleValue = True |
| |
|
| def set(self,value): |
def __init__(self,targetName,weak=False,provides=None): |
| """Set the value of the feature to value""" |
|
| self._set(value) |
self.targetNames = (targetName,) |
| |
self.weak = weak |
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self._provides=provides |
| |
|
| |
|
| def addItem(self,item): |
|
| """Add the item to the collection/relationship, reject if multiplicity exceeded""" |
|
| |
|
| ub = self.upperBound |
|
| |
|
| if not ub or len(self)<ub: |
|
| self._notifyLink(item) |
|
| self._link(item) |
|
| else: |
|
| raise ValueError |
|
| |
|
| |
|
| def removeItem(self,item): |
|
| """Remove the item from the collection/relationship, if present""" |
|
| self._unlink(item) |
|
| self._notifyUnlink(item) |
|
| |
|
| |
|
| def replaceItem(self,oldItem,newItem): |
|
| d = self._getData([]) |
|
| p = d.index(oldItem) |
|
| if p!=-1: |
|
| d[p]=newItem |
def computeValue(self, obj, instanceDict, attrName): |
| self._setData(d) |
|
| self._notifyUnlink(oldItem) |
names = self.targetNames |
| self._notifyLink(newItem) |
obs = map(obj.lookupComponent, names) |
| |
|
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for name,newOb in zip(names, obs): |
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|
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if newOb is NOT_FOUND: |
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|
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del instanceDict[attrName] |
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raise NameNotFoundError(attrName, resolvedName = name) |
| |
|
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if self.singleValue: |
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|
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if self.weak: |
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return ref(newOb) |
| else: |
else: |
| raise ValueError # XXX |
return newOb |
| |
|
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if self.weak: |
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obs = map(ref,obs) |
| |
|
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return tuple(obs) |
| |
|
| def __call__(self): |
|
| """Return the value of the feature""" |
|
| return self._getData() |
|
| |
|
| |
|
| def values(self): |
|
| """Return the value(s) of the feature as a sequence, even if it's a single value""" |
|
| return self._getData() |
|
| |
|
| |
|
| def clear(self): |
|
| """Unset the value of the feature (like __delattr__)""" |
|
| |
|
| referencedEnd = self.referencedEnd |
|
| |
|
| d = self._getData() |
|
| |
|
| if referencedEnd: |
|
| element = self.getElement() |
|
| for item in d: |
|
| otherEnd = getattr(item,referencedEnd) |
|
| otherEnd._unlink(element) |
|
| |
|
| if d: |
|
| self._delData() |
|
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|
| |
|
| def __len__(self): |
|
| return len(self._getData()) |
|
| |
|
| def isEmpty(self): |
|
| return len(self._getData())==0 |
|
| |
|
| def isReferenced(self,item): |
|
| return item in self._getData() |
|
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|
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class bindToNames(bindTo): |
| |
|
| def _notifyLink(self,item): |
"""Automatically look up and cache a sequence of services by name |
| referencedEnd = self.referencedEnd |
|
| if referencedEnd: |
|
| otherEnd = getattr(item,referencedEnd) |
|
| otherEnd._link(self.getElement()) |
|
| |
|
| def _notifyUnlink(self,item): |
Usage:: |
| referencedEnd = self.referencedEnd |
|
| if referencedEnd: |
|
| otherEnd = getattr(item,referencedEnd) |
|
| otherEnd._unlink(self.getElement()) |
|
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|
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class someClass(binding.AutoCreated): |
| |
|
| def _set(self,value): |
thingINeed = binding.bindToNames( |
| self.clear() |
"path/to/service", "another/path", ... |
| self._setData(value) |
) |
| |
|
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'someClass' can then refer to 'self.thingINeed' to get a tuple of |
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services instead of calling 'self.lookupComponent()' on a series of |
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names. As with 'bindTo()', a 'weak' keyword argument can be set to |
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indicate that the sequence should consist of weak references to the |
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named objects. |
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""" |
| |
|
| def _link(self,element): |
singleValue = False |
| d=self._getData([]) |
|
| d.append(element) |
|
| self._setData(d) |
|
| |
|
| def _unlink(self,element): |
def __init__(self, *targetNames, **kw): |
| d=self._getData([]) |
self.targetNames = targetNames |
| d.remove(element) |
self.weak = kw.get('weak') |
| self._setData(d) |
self._provides = kw.get('provides') |
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|
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|
| class Reference(Collection): |
|
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|
| __implements__ = IReference |
|
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|
| upperBound = 1 |
class bindToParent(WeakBinding): |
| |
|
| def __call__(self): |
"""Look up and cache a weak ref to the nth-level parent component |
| """Return the value of the feature""" |
|
| return self._getData(None) |
|
| |
|
| def _set(self,value): |
Usage:: |
| self.clear() |
|
| self._setData([value]) |
|
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|
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class someClass(binding.AutoCreated): |
| |
|
| class Sequence(Collection): |
grandPa = binding.bindToParent(2) |
| |
|
| __implements__ = ISequence |
'someClass' can then refer to 'self.grandPa' instead of calling |
| |
'self.getParentComponent().getParentComponent()'. |
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""" |
| |
|
| isOrdered = 1 |
def __init__(self,level=1,provides=None): |
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self.level = level |
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self._provides = provides |
| |
|
| def insertBefore(self,oldItem,newItem): |
def computeValue(self, obj, instDict, attrName): |
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|
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for step in range(self.level): |
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newObj = obj.getParentComponent() |
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if newObj is None: break |
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obj = newObj |
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|
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return obj |
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|
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def bindToSelf(provides=None): |
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|
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"""Weak reference to the 'self' object |
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|
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This is just a shortcut for 'bindToParent(0)', and does pretty much what |
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you'd expect. It's handy for objects that provide default support for |
| |
various interfaces in the absence of an object to delegate to. The object |
| |
can refer to 'self.delegateForInterfaceX.someMethod()', and have |
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'delegateForInterfaceX' be a 'bindToSelf()' by default.""" |
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|
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return bindToParent(0,provides) |
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|
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|
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class requireBinding(Once): |
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|
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"""Placeholder for a binding that should be (re)defined by a subclass""" |
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|
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def __init__(self,description="",provides=None): |
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self.description = description |
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self._provides = provides |
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|
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def computeValue(self, obj, instanceDict, attrName): |
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|
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raise NameError("Class %s must define %s; %s" |
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% (obj.__class__.__name__, attrName, self.description) |
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) |
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class Component(object): |
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|
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"""Thing that can be composed into a component tree, w/binding & lookups""" |
| |
|
| |
__metaclasses__ = ( |
| |
meta.AssertInterfaces, meta.ActiveDescriptors |
| |
) |
| |
|
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# use the global lookupComponent function as a method |
| |
|
| |
lookupComponent = lookupComponent |
| |
|
| |
def setParentComponent(self,parent): |
| |
from weakref import ref |
| |
self.getParentComponent = ref(parent) |
| |
|
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def getParentComponent(self): |
| |
return None |
| |
|
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def _componentName(self, dict, name): |
| |
return self.__class__.__name__.split('.')[-1] |
| |
|
| |
_componentName = Once(_componentName) |
| |
|
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__instance_provides__ = New(EigenRegistry) |
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|
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__class_provides__ = EigenRegistry() |
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def acquireUtility(self, iface, forObj=None, localLookup=True): |
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if forObj is None: |
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forObj=self |
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if localLookup: |
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provider = self.__instance_provides__.get(iface) |
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if provider is not None: |
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return provider(self,forObj) |
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attr = self.__class_provides__.get(iface) |
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if attr is not None: |
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utility = getattr(self,attr) |
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if utility is not NOT_FOUND: |
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return utility |
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parent = self.getParentComponent() |
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if parent is None: |
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parent = config.getLocal(self) |
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return parent.acquireUtility(iface,forObj) |
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def registerProvider(self, ifaces, provider): |
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self.__instance_provides__.register(ifaces, provider) |
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class AutoCreatable(type): |
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"""Metaclass for components which auto-create when used""" |
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def __get__(self, obj, typ=None): |
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if obj is None: |
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return self |
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newOb = self(obj) |
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obj.__dict__[newOb._componentName] = newOb |
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return newOb |
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class AutoCreated(Component): |
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"""Component that auto-creates itself in instances of its containing class |
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""" |
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__metaclasses__ = AutoCreatable, |
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def __init__(self, parent=None): |
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super(AutoCreated,self).__init__() |
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if parent is not None: |
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self.setParentComponent(parent) |
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| d = self._getData([]) |
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| ub = self.upperBound |
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| if ub and len(d)>=ub: |
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| raise ValueError # XXX |
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| i = -1 |
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| if d: i = d.index(element) |
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| if i!=-1: |
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| d.insert(i,newItem) |
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| self._setData(d) |
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| self._notifyLink(newItem) |
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| else: |
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| raise ValueError # XXX |
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|
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|
| class Classifier(StaticBinding, Base): |
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| """Basis for all flavors""" |
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| class PrimitiveType(Classifier): |
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| """A primitive type (e.g. Boolean, String, etc.)""" |
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| class Enumeration(DynamicBinding, Classifier): |
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| """An enumerated type""" |
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| class DataType(Classifier): |
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| """A complex datatype""" |
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| class Element(DataType): |
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| """An element in its own right""" |
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| __implements__ = IElement |
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| setupModule() |
modules.setupModule() |
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Diff of /PEAK/src/peak/binding/components.py
Parent Directory
| 
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