Re-usable, serializable priority queue implementation
SplPriorityQueue acts as a heap; on iteration, each item is removed from the queue. If you wish to re-use such a queue, you need to clone it first. This makes for some interesting issues if you wish to delete items from the queue, or, as already stated, iterate over it multiple times.
This class aggregates items for the queue itself, but also composes an “inner” iterator in the form of an SplPriorityQueue object for performing the actual iteration.
Insert an item into the queue
Priority defaults to 1 (low priority) if none provided.
| Parameters: |
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| Return type: | PriorityQueue |
Remove an item from the queue
This is different than {@link extract()}; its purpose is to dequeue an item.
This operation is potentially expensive, as it requires re-initialization and re-population of the inner queue.
Note: this removes the first item matching the provided item found. If the same item has been added multiple times, it will not remove other instances.
| Parameters: | mixed – |
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| Return type: | bool False if the item was not found, true otherwise. |
How many items are in the queue?
| Return type: | int |
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Peek at the top node in the queue, based on priority.
| Return type: | mixed |
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Extract a node from the inner queue and sift up
| Return type: | mixed |
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Retrieve the inner iterator
SplPriorityQueue acts as a heap, which typically implies that as items are iterated, they are also removed. This does not work for situations where the queue may be iterated multiple times. As such, this class aggregates the values, and also injects an SplPriorityQueue. This method retrieves the inner queue object, and clones it for purposes of iteration.
| Return type: | SplPriorityQueue |
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Serialize the data structure
| Return type: | string |
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Unserialize a string into a PriorityQueue object
Serialization format is compatible with {@link ZendStdlibSplPriorityQueue}
| Parameters: | string – |
|---|---|
| Return type: | void |
Serialize to an array
By default, returns only the item data, and in the order registered (not sorted). You may provide one of the EXTR_* flags as an argument, allowing the ability to return priorities or both data and priority.
| Parameters: | int – |
|---|---|
| Return type: | array |
Does the queue contain the given datum?
| Parameters: | mixed – |
|---|---|
| Return type: | bool |
Does the queue have an item with the given priority?
| Parameters: | int – |
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| Return type: | bool |