48 lines
1.9 KiB
Markdown
48 lines
1.9 KiB
Markdown
|
# State tracking design
|
||
|
|
|
||
|
|
objectPool
|
||
|
|
- constructor takes options for factory methods
|
||
|
|
- create [required]
|
||
|
|
- destroy [required]
|
||
|
|
- validate [optional]
|
||
|
|
- activate [optional, new]
|
||
|
|
- passivate [optional, new]
|
||
|
|
|
||
|
|
- internals
|
||
|
|
- idleObjects : linkedlist
|
||
|
|
- allObjects : object where, key = object, value = wrapper; what is the equivalent of a Java ConcurrentHashMap in javascript
|
||
|
|
this holds all objects associated with the pool in any state apart from destroyed.
|
||
|
|
use https://www.npmjs.com/package/hashmap
|
||
|
|
|
||
|
|
|
||
|
|
pooledObject
|
||
|
|
wraps an object/resource
|
||
|
|
- id (internal)
|
||
|
|
- resource/object
|
||
|
|
- state
|
||
|
|
- createTime
|
||
|
|
- lastBorrowTime
|
||
|
|
- lastUseTime
|
||
|
|
- lastReturnTime
|
||
|
|
- borrowCount
|
||
|
|
|
||
|
|
pooled object states
|
||
|
|
- IDLE : in the queue, not in use
|
||
|
|
- ALLOCATED : in use
|
||
|
|
- EVICTION : In the queue, currently being tested for possible eviction.
|
||
|
|
- EVICTION_RETURN_TO_HEAD : Not in the queue, currently being tested for possible eviction. An
|
||
|
|
attempt to borrow the object was made while being tested which removed it
|
||
|
|
from the queue. It should be returned to the head of the queue once
|
||
|
|
eviction testing completes.
|
||
|
|
- VALIDATION : In the queue, currently being validated
|
||
|
|
- VALIDATION_PREALLOCATED : Not in queue, currently being validated. The object was borrowed while
|
||
|
|
being validated and since testOnBorrow was configured, it was removed
|
||
|
|
from the queue and pre-allocated. It should be allocated once validation
|
||
|
|
completes.
|
||
|
|
- VALIDATION_RETURN_TO_HEAD : Not in queue, currently being validated. An attempt to borrow the object
|
||
|
|
was made while previously being tested for eviction which removed it from
|
||
|
|
the queue. It should be returned to the head of the queue once validation
|
||
|
|
completes.
|
||
|
|
- INVALID : Failed maintenance (e.g. eviction test or validation) and will be / has been destroyed
|
||
|
|
- ABANDONED : Deemed abandoned, to be invalidated.
|
||
|
|
- RETURNING : Returning to the pool
|