class Atom(ARef):
"""A thread-safe mutable object."""
def __init__(self, state, meta=None):
"""Instantiate an Atom to the given state.
state -- any object
meta -- meta data to attach"""
super(Atom, self).__init__(meta)
self._state = AtomicReference(state)
def deref(self):
"""Return this Atom's current state."""
return self._state.get()
def swap(self, *args):
"""Change this Atom's current state.
args must be one of:
* IFn
* IFn, object
* IFn, object, object
* IFn, object, object, ISeq
An ArityException will be raised otherwise.
Return the result of calling IFn with the current state of this Atom
as its first argument and the remaining arguments to this method."""
func = None
if 0 < len(args) <= 3:
ifn = args[0]
args = args[1:]
func = lambda v: ifn(v, *args)
elif len(args) == 4:
ifn = args[0]
arg1, arg2, args = args[1:]
func = lambda v: ifn(v, arg1, arg2, *args)
else:
raise ArityException("Atom.swap() expected 1 to 4 arguments,"
" got: ({})".format(len(args)))
while True:
val = self.deref()
newv = func(val)
self.validate(newv)
if self._state.compareAndSet(val, newv):
self.notifyWatches(val, newv)
return newv
def compareAndSet(self, oldv, newv):
"""Set the state of this Atom to newv.
oldv -- Any object. The expected current state of this Atom.
newv -- any object
If the current state of this Atom is oldv set it to newv. A
validator, if one exists is called prior to setting. Any watches are
notified after successfully setting.
Return True if successful, False otherwise."""
self.validate(newv)
ret = self._state.compareAndSet(oldv, newv)
if ret is not None:
self.notifyWatches(oldv, newv)
return ret
def reset(self, newval):
"""Reset this Atom's state to newval.
newval -- any object
A validator, if one exists is called prior to resetting.
Any watches are notified after resetting.
Return newval"""
oldval = self._state.get()
self.validate(newval)
self._state.set(newval)
self.notifyWatches(oldval, newval)
return newval
class Atom(ARef):
"""A thread-safe mutable object."""
def __init__(self, state, meta=None):
"""Instantiate an Atom to the given state.
state -- any object
meta -- meta data to attach"""
super(Atom, self).__init__(meta)
self._state = AtomicReference(state)
def deref(self):
"""Return this Atom's current state."""
return self._state.get()
def swap(self, *args):
"""Change this Atom's current state.
args must be one of:
* IFn
* IFn, object
* IFn, object, object
* IFn, object, object, ISeq
An ArityException will be raised otherwise.
Return the result of calling IFn with the current state of this Atom
as its first argument and the remaining arguments to this method."""
func = None
if len(args) == 1:
ifn = args[0]
func = lambda v: ifn(v)
elif len(args) == 2:
ifn, arg = args
func = lambda v: ifn(v, arg)
elif len(args) == 3:
ifn, arg1, arg2 = args
func = lambda v: ifn(v, arg1, arg2)
elif len(args) == 4:
ifn, arg2, arg3, arg4 = args
func = lambda v: apply(ifn, v, arg2, arg3, list(arg4))
else:
raise ArityException("Atom.swap() expected 1 to 4 arguments,"
" got: ({})".format(len(args)))
while True:
val = self.deref()
newv = func(val)
self.validate(newv)
if self._state.compareAndSet(val, newv):
self.notifyWatches(val, newv)
return newv
def compareAndSet(self, oldv, newv):
"""Set the state of this Atom to newv.
oldv -- Any object. The expected current state of this Atom.
newv -- any object
If the current state of this Atom is oldv set it to newv. A
validator, if one exists is called prior to setting. Any watches are
notified after successfully setting.
Return True if successful, False otherwise."""
self.validate(newv)
ret = self._state.compareAndSet(oldv, newv)
if ret is not None:
self.notifyWatches(oldv, newv)
return ret
def reset(self, newval):
"""Reset this Atom's state to newval.
newval -- any object
A validator, if one exists is called prior to resetting.
Any watches are notified after resetting.
Return newval"""
oldval = self._state.get()
self.validate(newval)
self._state.set(newval)
self.notifyWatches(oldval, newval)
return newval
