Queue¶
- class Queue(service_name, name, context)[source]¶
Bases:
PartitionSpecificProxy
[BlockingQueue
],Generic
[ItemType
]Concurrent, blocking, distributed, observable queue.
Queue is not a partitioned data-structure. All of the Queue content is stored in a single machine (and in the backup). Queue will not scale by adding more members in the cluster.
- add(item: ItemType) Future[bool] [source]¶
Adds the specified item to this queue if there is available space.
- Parameters:
item – The specified item.
- Returns:
True
if element is successfully added,False
otherwise.
- add_all(items: Sequence[ItemType]) Future[bool] [source]¶
Adds the elements in the specified collection to this queue.
- Parameters:
items – Collection which includes the items to be added.
- Returns:
True
if this queue is changed after call,False
otherwise.
- add_listener(include_value: bool = False, item_added_func: Optional[Callable[[ItemEvent[ItemType]], None]] = None, item_removed_func: Optional[Callable[[ItemEvent[ItemType]], None]] = None) Future[str] [source]¶
- Adds an item listener for this queue. Listener will be notified for
all queue add/remove events.
- Parameters:
include_value – Whether received events include the updated item or not.
item_added_func – Function to be called when an item is added to this set.
item_removed_func – Function to be called when an item is deleted from this set.
- Returns:
A registration id which is used as a key to remove the listener.
- contains(item: ItemType) Future[bool] [source]¶
Determines whether this queue contains the specified item or not.
- Parameters:
item – The specified item to be searched.
- Returns:
True
if the specified item exists in this queue,False
otherwise.
- contains_all(items: Sequence[ItemType]) Future[bool] [source]¶
Determines whether this queue contains all of the items in the specified collection or not.
- Parameters:
items – The specified collection which includes the items to be searched.
- Returns:
True
if all of the items in the specified collection exist in this queue,False
otherwise.
- drain_to(target_list: List[ItemType], max_size: int = -1) Future[int] [source]¶
Transfers all available items to the given target_list and removes these items from this queue.
If a max_size is specified, it transfers at most the given number of items. In case of a failure, an item can exist in both collections or none of them.
This operation may be more efficient than polling elements repeatedly and putting into collection.
- Parameters:
target_list – the list where the items in this queue will be transferred.
max_size – The maximum number items to transfer.
- Returns:
Number of transferred items.
- iterator() Future[List[ItemType]] [source]¶
Returns all the items in this queue.
- Returns:
Collection of items in this queue.
- is_empty() Future[bool] [source]¶
Determines whether this set is empty or not.
- Returns:
True
if this queue is empty,False
otherwise.
- offer(item: ItemType, timeout: float = 0) Future[bool] [source]¶
Inserts the specified element into this queue if it is possible to do so immediately without violating capacity restrictions.
If there is no space currently available:
If the timeout is provided, it waits until this timeout elapses and returns the result.
If the timeout is not provided, returns
False
immediately.
- Parameters:
item – The item to be added.
timeout – Maximum time in seconds to wait for addition.
- Returns:
True
if the element was added to this queue,False
otherwise.
- peek() Future[Optional[ItemType]] [source]¶
Retrieves the head of queue without removing it from the queue.
- Returns:
The head of this queue, or
None
if this queue is empty.
- poll(timeout: float = 0) Future[Optional[ItemType]] [source]¶
Retrieves and removes the head of this queue.
If this queue is empty:
If the timeout is provided, it waits until this timeout elapses and returns the result.
If the timeout is not provided, returns
None
.
- Parameters:
timeout – Maximum time in seconds to wait for addition.
- Returns:
The head of this queue, or
None
if this queue is empty or specified timeout elapses before an item is added to the queue.
- put(item: ItemType) Future[None] [source]¶
Adds the specified element into this queue.
If there is no space, it waits until necessary space becomes available.
- Parameters:
item – The specified item.
- remaining_capacity() Future[int] [source]¶
Returns the remaining capacity of this queue.
- Returns:
Remaining capacity of this queue.
- remove(item: ItemType) Future[bool] [source]¶
Removes the specified element from the queue if it exists.
- Parameters:
item – The specified element to be removed.
- Returns:
True
if the specified element exists in this queue,False
otherwise.
- remove_all(items: Sequence[ItemType]) Future[bool] [source]¶
Removes all of the elements of the specified collection from this queue.
- Parameters:
items – The specified collection.
- Returns:
True
if the call changed this queue,False
otherwise.
- remove_listener(registration_id: str) Future[bool] [source]¶
Removes the specified item listener.
Returns silently if the specified listener was not added before.
- Parameters:
registration_id – Id of the listener to be deleted.
- Returns:
True
if the item listener is removed,False
otherwise.
- retain_all(items: Sequence[ItemType]) Future[bool] [source]¶
Removes the items which are not contained in the specified collection.
In other words, only the items that are contained in the specified collection will be retained.
- Parameters:
items – Collection which includes the elements to be retained in this set.
- Returns:
True
if this queue changed as a result of the call,False
otherwise.
- size() Future[int] [source]¶
Returns the number of elements in this collection.
If the size is greater than
2**31 - 1
, it returns2**31 - 1
.- Returns:
Size of the queue.
- take() Future[ItemType] [source]¶
Retrieves and removes the head of this queue, if necessary, waits until an item becomes available.
- Returns:
The head of this queue.
- blocking() BlockingQueue[ItemType] [source]¶
Returns a version of this proxy with only blocking method calls.
- class BlockingQueue(wrapped: Queue[ItemType])[source]¶
Bases:
Queue
[ItemType
]- name¶
- service_name¶
- add(item: ItemType) bool [source]¶
Adds the specified item to this queue if there is available space.
- Parameters:
item – The specified item.
- Returns:
True
if element is successfully added,False
otherwise.
- add_all(items: Sequence[ItemType]) bool [source]¶
Adds the elements in the specified collection to this queue.
- Parameters:
items – Collection which includes the items to be added.
- Returns:
True
if this queue is changed after call,False
otherwise.
- add_listener(include_value: bool = False, item_added_func: Optional[Callable[[ItemEvent[ItemType]], None]] = None, item_removed_func: Optional[Callable[[ItemEvent[ItemType]], None]] = None) str [source]¶
- Adds an item listener for this queue. Listener will be notified for
all queue add/remove events.
- Parameters:
include_value – Whether received events include the updated item or not.
item_added_func – Function to be called when an item is added to this set.
item_removed_func – Function to be called when an item is deleted from this set.
- Returns:
A registration id which is used as a key to remove the listener.
- contains(item: ItemType) bool [source]¶
Determines whether this queue contains the specified item or not.
- Parameters:
item – The specified item to be searched.
- Returns:
True
if the specified item exists in this queue,False
otherwise.
- contains_all(items: Sequence[ItemType]) bool [source]¶
Determines whether this queue contains all of the items in the specified collection or not.
- Parameters:
items – The specified collection which includes the items to be searched.
- Returns:
True
if all of the items in the specified collection exist in this queue,False
otherwise.
- drain_to(target_list: List[ItemType], max_size: int = -1) int [source]¶
Transfers all available items to the given target_list and removes these items from this queue.
If a max_size is specified, it transfers at most the given number of items. In case of a failure, an item can exist in both collections or none of them.
This operation may be more efficient than polling elements repeatedly and putting into collection.
- Parameters:
target_list – the list where the items in this queue will be transferred.
max_size – The maximum number items to transfer.
- Returns:
Number of transferred items.
- iterator() List[ItemType] [source]¶
Returns all the items in this queue.
- Returns:
Collection of items in this queue.
- is_empty() bool [source]¶
Determines whether this set is empty or not.
- Returns:
True
if this queue is empty,False
otherwise.
- offer(item: ItemType, timeout: float = 0) bool [source]¶
Inserts the specified element into this queue if it is possible to do so immediately without violating capacity restrictions.
If there is no space currently available:
If the timeout is provided, it waits until this timeout elapses and returns the result.
If the timeout is not provided, returns
False
immediately.
- Parameters:
item – The item to be added.
timeout – Maximum time in seconds to wait for addition.
- Returns:
True
if the element was added to this queue,False
otherwise.
- peek() Optional[ItemType] [source]¶
Retrieves the head of queue without removing it from the queue.
- Returns:
The head of this queue, or
None
if this queue is empty.
- poll(timeout: float = 0) Optional[ItemType] [source]¶
Retrieves and removes the head of this queue.
If this queue is empty:
If the timeout is provided, it waits until this timeout elapses and returns the result.
If the timeout is not provided, returns
None
.
- Parameters:
timeout – Maximum time in seconds to wait for addition.
- Returns:
The head of this queue, or
None
if this queue is empty or specified timeout elapses before an item is added to the queue.
- put(item: ItemType) None [source]¶
Adds the specified element into this queue.
If there is no space, it waits until necessary space becomes available.
- Parameters:
item – The specified item.
- remaining_capacity() int [source]¶
Returns the remaining capacity of this queue.
- Returns:
Remaining capacity of this queue.
- remove(item: ItemType) bool [source]¶
Removes the specified element from the queue if it exists.
- Parameters:
item – The specified element to be removed.
- Returns:
True
if the specified element exists in this queue,False
otherwise.
- remove_all(items: Sequence[ItemType]) bool [source]¶
Removes all of the elements of the specified collection from this queue.
- Parameters:
items – The specified collection.
- Returns:
True
if the call changed this queue,False
otherwise.
- remove_listener(registration_id: str) bool [source]¶
Removes the specified item listener.
Returns silently if the specified listener was not added before.
- Parameters:
registration_id – Id of the listener to be deleted.
- Returns:
True
if the item listener is removed,False
otherwise.
- retain_all(items: Sequence[ItemType]) bool [source]¶
Removes the items which are not contained in the specified collection.
In other words, only the items that are contained in the specified collection will be retained.
- Parameters:
items – Collection which includes the elements to be retained in this set.
- Returns:
True
if this queue changed as a result of the call,False
otherwise.
- size() int [source]¶
Returns the number of elements in this collection.
If the size is greater than
2**31 - 1
, it returns2**31 - 1
.- Returns:
Size of the queue.
- take() ItemType [source]¶
Retrieves and removes the head of this queue, if necessary, waits until an item becomes available.
- Returns:
The head of this queue.
- destroy() bool [source]¶
Destroys this proxy.
- Returns:
True
if this proxy is destroyed successfully,False
otherwise.
- blocking() BlockingQueue[ItemType] [source]¶
Returns a version of this proxy with only blocking method calls.