Stephen Colebourne wrote:
It might be better named something like "PriorityBuffer" since that matches the behavior.I have made the following changes: - PriorityQueue now disapproved (not deprecated, but the language indicates it is) - BinaryHeap in main package is not deprecated, as it is the only implementation of PQ - BinaryHeap in buffer subpackage renamed to BinaryBuffer. No longer implements PQ
- PQ decorators now inner classes of PQUtils
We could go further and actually deprecated PQ. But I'm a little wary of that.
We should decide whether or not Queue implementations belong in [collections]. I am +0 on this (the "+" is because BinaryHeap/Buffer exists). If no, we should deprecate. See below.
(And both BinaryHeap and BinaryBuffer still need their remove bug fixing :-)
As noted in bug report, I have a fix ready to commit. What I don't like about the setup above is that this and all other fixes / enhancements need to be applied to both classes.
Stephen
----- Original Message ----- From: "Stephen Colebourne" <[EMAIL PROTECTED]>
BinaryHeap is a very old collections class, originally from Avalon. It implements PriorityQueue interface.
PQ is an interface that does not extend Collection, Buffer is effectively the replacement that does. They use different terms though - PQ insert/peek/pop - Buffer add/get/remove. PQ is also badly named as the interface specifies nothing about 'priority'.
Ack. Maybe should just be called "Queue." As noted below, however, the only impl in [collections] is a heap-backed priority queue.
Currently I have moved BinaryHeap and the PriorityQueue decorators into
the
buffer subpackage (as they seem related). But is this right???
Sorry to respond late on this, but it does not seem right to me. I see the BinaryHeap/Buffer impl as a array-heap-backed implementation of a priority queue. The interface is a Queue interface, which, as you point out is different from a buffer interface.
Possibilities:
a) BinaryHeap and PQ decorators in buffer subpackage
b) BinaryHeap and PQ decorators in (new) priorityqueue subpackage
c) BinaryHeap left in main package where it always was, PQ decorators as hidden inner classes on PriorityQueueUtils.
I think I favour (c), as I'm not a fan of the PQ interface, and this would avoid change for this dubious (but probably useful) class/interface.
Here is a logical alternative:
1) Deprecate PriorityQueue interface in favor of Queue.
2) Create a queue package and put BinaryHeap there (maybe renamed something like HeapPriorityQueue or BinaryPriorityQueue or even PriorityQueue). This would open the door for other queue implementations.
I understand that this departs from the general pattern of sticking with things that extend collection, but it is more natural to me at least.
Phil
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