Add queues will alternative fetch orders (priority based and stack based).
diff --git a/Lib/Queue.py b/Lib/Queue.py
index ce34024..7b0b328 100644
--- a/Lib/Queue.py
+++ b/Lib/Queue.py
@@ -2,8 +2,9 @@
from time import time as _time
from collections import deque
+import heapq
-__all__ = ['Empty', 'Full', 'Queue']
+__all__ = ['Empty', 'Full', 'Queue', 'PriorityQueue', 'LifoQueue']
class Empty(Exception):
"Exception raised by Queue.get(block=0)/get_nowait()."
@@ -196,7 +197,7 @@
def _init(self, maxsize):
self.queue = deque()
- def _qsize(self):
+ def _qsize(self, len=len):
return len(self.queue)
# Put a new item in the queue
@@ -206,3 +207,38 @@
# Get an item from the queue
def _get(self):
return self.queue.popleft()
+
+
+class PriorityQueue(Queue):
+ '''Variant of Queue that retrieves open entries in priority order (lowest first).
+
+ Entries are typically tuples of the form: (priority number, data).
+ '''
+
+ def _init(self, maxsize):
+ self.queue = []
+
+ def _qsize(self, len=len):
+ return len(self.queue)
+
+ def _put(self, item, heappush=heapq.heappush):
+ heappush(self.queue, item)
+
+ def _get(self, heappop=heapq.heappop):
+ return heappop(self.queue)
+
+
+class LifoQueue(Queue):
+ '''Variant of Queue that retrieves most recently added entries first.'''
+
+ def _init(self, maxsize):
+ self.queue = []
+
+ def _qsize(self, len=len):
+ return len(self.queue)
+
+ def _put(self, item):
+ self.queue.append(item)
+
+ def _get(self):
+ return self.queue.pop()