class QueueAsLinkedList(Queue):
__slots__ = ['__list']
def __init__(self):
super(QueueAsLinkedList, self).__init__()
self.__list = LinkedList()
def purge(self):
self.__list.purge()
def getHead(self):
return self.__list.getFirst()
# getfirst ya hace las siguientes comprobaciones
#if self.__list.getIsEmpty():
# raise IndexError("Empty")
#else:
# return self.__list.getHead()
def enqueue(self, obj):
self.__list.append(obj)
# el append de linkedlist ya hace las comprobaciones pertinentes
def dequeue(self):
item = self.__list.getFirst()
self.__list.extract(self.__list.getFirst())
return item
# el extract de linkedlist ya hace las comprobaciones de lista vacia
def accept(self, visitor):
assert isinstance(visitor, Visitor)
ptr = self.__list.head
while ptr is not None:
visitor.visit(ptr.data)
if visitor.isDone:
return
ptr = ptr.next
def getIsEmpty(self):
return self.__list.getIsEmpty()
class Iterator(Iterator):
__slots__ = ['__position']
def __init__(self, queue):
super(QueueAsLinkedList.Iterator,self).__init__(queue)
self.__position = None
def next(self):
if self.__position is None:
self.__position = self.container._QueueAsLinkedList__list.head
else:
self.__position = self.__position.next
if self.__position is None:
raise StopIteration
return self.__position.data
def __iter__(self):
return self.Iterator(self)
def _compareTo(self, obj):
assert isinstance(self, obj.__class__)
raise NotImplementedError
class OrderedSequenceAsLinkedList(OrderedSequence):
""" Ordered sequence implemented using a linked list.
"""
__slots__ = ['__list']
def __init__(self):
""" (OrderedSequenceAsLinkedList) -> None
Constructs an ordered sequence.
"""
super(OrderedSequenceAsLinkedList, self).__init__()
self.__list = LinkedList()
self.count = 0
def insert(self, obj):
""" (OrderedSequenceAsLinkedList, Object) -> None
Inserts the given object at the end of this sequence.
"""
self.__list.append(obj)
self.count +=1
def __getitem__(self, offset):
""" (OrderedSequenceAsLinkedList, int) -> Object
Returns the object in this sequence at the given offset.
"""
counter = 0
if offset < 0:
raise IndexError()
else:
temp = self.__list.head
while temp is not None:
if counter is offset:
return temp.data
counter += 1
temp = temp.next
if offset > counter:
raise IndexError()
def purge(self):
""" (OrderedSequenceAsLinkedList) -> None
Purges this ordered sequence.
"""
self.__list = LinkedList()
self.count = 0
def accept(self, visitor):
""" (OrderedSequenceAsLinkedList, Visitor) -> None
Makes the given visitor visit all the objects in this ordered sequence.
"""
assert isinstance(visitor, Visitor)
ptr = self.__list.head
while ptr is not None:
visitor.visit(ptr.data)
if visitor.isDone:
return
ptr = ptr.next
def __contains__(self, obj):
""" (OrderedSequenceAsLinkedList, Object) -> bool
Returns true if the given object instance is in this ordered sequence.
"""
if self.__list.isEmpty is True:
return False
temp = self.__list.head
while temp is not None:
if temp.data is obj:
return True
temp = temp.next
return False
def find(self, arg):
""" (OrderedSequenceAsLinkedList, Object) -> Object
Finds an object in this ordered sequence that equals the given object.
"""
if self.__list.isEmpty:
return None
temp = self.__list.head
while temp is not None:
if temp.data is arg:
return temp.data
temp = temp.next
return None
def withdraw(self, obj):
""" (OrderedSequenceAsLinkedList, Object) -> None
Withdraws the given object instance from this ordered sequence.
"""
if self.__list.isEmpty is True:
raise IndexError()
else:
self.__list.extract(obj)
if self.count > 0:
self.count -= 1
def findPosition(self, obj):
""" (OrderedSequenceAsLinkedList, Object) -> OrderedSequenceAsLinkedList.Cursor
Finds the position of an object in this sequence that equals the given
object and returns a cursor that refers to that object.
"""
ptr = self.__list.head
while ptr is not None:
if ptr.data is obj:
return self.Cursor(self,ptr)
ptr = ptr.next
return self.Cursor(None,None)
class Cursor(Cursor):
"""
A cursor that refers to an object in an ordered list.
"""
__slots__ = ['__element']
def __init__(self, lis, element):
""" (OrderedSequenceAsLinkedList.Cursor, OrderedSequenceAsLinkedList,
LinkedList.Element) -> None
Constructs a cursor that refers to the object in the given element
of the given sequence.
"""
super(OrderedSequenceAsLinkedList.Cursor, self).__init__(lis)
self.__element = element
def getData(self):
""" (OrderedSequenceAsLinkedList.Cursor) -> Object
Returns the object to which this cursor refers.
"""
if self.__element is not None:
return self.__element.getData()
else:
raise IndexError()
def insertAfter(self, obj):
""" (OrderedSequenceAsLinkedList.Cursor, Object) -> None
Inserts the given object into the sequence after the
object to which this cursor refers.
"""
if self.__element is None:
raise IndexError
self.__element.insertAfter(obj)
self.__sequence.count += 1
def insertBefore(self, obj):
""" (OrderedSequenceAsLinkedList.Cursor, Object) -> None
Inserts the given object into the sequence before the
object to which this cursor refers.
"""
if self.__element is None:
raise IndexError
self.__element.insertBefore(obj)
self.__sequence.count += 1
def withdraw(self):
""" (OrderedSequenceAsLinkedList.Cursor) -> None
Withdraws from the sequence the object to which this cursor refers.
"""
if self.__element is None:
raise IndexError()
self.__sequence._OrderedSequenceAsLinkedList__list.extract(self.__element.data)
self.__sequence.count -= 1
class Iterator(Iterator):
""" Enumerates the items in an ordered sequence.
"""
__slots__ = ['__element']
def __init__(self, lis):
""" (OrderedSequenceAsLinkedList.Iterator, OrderedSequenceAsLinkedList) -> None
Constructs an iterator for the given sequence.
"""
super(OrderedSequenceAsLinkedList.Iterator, self).__init__(lis)
self.__element = None
def next(self):
""" (OrderedSequenceAsLinkedList.Iterator) -> Object
Returns the next element.
"""
if self.container.isEmpty:
raise StopIteration()
if self.__element is None:
self.__element = self.container._OrderedSequenceAsLinkedList__list.head
elif self.__element.next is None:
self.__element = None
raise StopIteration()
else:
self.__element = self.__element.next
return self.__element.data
def __iter__(self):
""" (OrderedSequenceAsLinkedList) -> OrderedSequenceAsLinkedList.Iterator
Returns an iterator for this ordered sequence.
"""
return self.Iterator(self)
def _compareTo(self, obj):
""" (OrderedSequenceAsLinkedList, OrderedSequenceAsLinkedList) -> int
Compares this ordered list with the given ordered sequence.
"""
assert isinstance(self, obj.__class__)
raise TypeError, 'Not Implemented'
@staticmethod
def main(*argv):
"OrderedSequenceAsLinkedList test program."
print OrderedSequenceAsLinkedList.main.__doc__
lis = OrderedSequenceAsLinkedList()
OrderedSequence.test(lis)
return 0
