[Feature] Auto Populate List

[chrisjenx]

I was of the understanding that cache.list() would be backed completely by the cache object. But it's very confusing api when cache and list are independent of each other, for example:

I would expect this to work:

val cache = kottage.cache( //...
val list = cache.list( // ...

// I thought cache was backing the list 
cache.put("id", TestClass())
val results = list.getPageFrom(null, null)
results.items shouldHaveSize 1 // fails 

This creates some confusing API interactions, now I want to update a value based on key, if I don't handle that gracefully:

cache.put("id", TestClass())
list.addKey("id")
// Then update later
cache.put("id", TestClass())
list.addKey("id")

// I now get:
val results = list.getPageFrom(null, null)
results.items shouldHaveSize 1 // fails because the equals 2

// I have to wrap in something like:
    open suspend fun put(key: String, value: T) {
        val exists = cache.exists(key)
        cache.put(key, value, type)
        if (!exists) list.addKey(key)
    }

Either:

• List should be created directly from kottage.list() that way theres no way to get into weird states and you only interact with the list api. (Would need to add, get(key)/replace(key)/remove(key) to make that useable.

Or:

• list should be automatically backed by the cache:

  
  cache.put(key, value)

val results = list.getPageFrom(null, null) results.items shouldHaveSize 1 // should succeed because the list is backed by the cache

Thoughts?

[irgaly]

I agree with you that the Kottage List feature has complex API and confusable...

• Kottage Cache is a KVS storage, and a backing storage of Kottage List.
• Kottage List is Linked List, and they have only reference to the itmes in Kottage Cache.
  • Also, multiple Kottage Lists can be created from same Kottage Cache.

The items of Kottage List may have same reference to items in Kottage Cache.

val cache = kottage.cache("cache A")
val list = cache.list("list A")
cache.put("other", ...) // add new "other" item to Cache
list.add("item1", ...) // add new "item1" item to Cache and List
list.add("item2", ...) // add new "item2" item to Cache and List
list.add("item3", ...) // add new "item3" item to Cache and List
list.add("item1") // add "item1" item from Cache to List
list.add("item2") // add "item2" item from Cache to List

// cache has 4 items
// list has 5 items

This will be:

flowchart LR
  subgraph cacheA["cache A (like Map<String, Any>)"]
    item1["key = 'item1'<br/>value = '...'"]
    item2["key = 'item2'<br/>value = '...'"]
    item3["key = 'item3'<br/>value = '...'"]
    other["key = 'other'<br/>value = '...'"]
  end
  subgraph listA["list A (like LinkedList)"]
    listItem1["list item 1 (reference to 'item1')"]
    listItem2["list item 2 (reference to 'item2')"]
    listItem3["list item 3 (reference to 'item3')"]
    listItem4["list item 4 (reference to 'item1')"]
    listItem5["list item 5 (reference to 'item2')"]
  end
  listItem1 ==> listItem2
  listItem2 ==> listItem3
  listItem3 ==> listItem4
  listItem4 ==> listItem5
  listItem1 -. ref .-> item1
  listItem2 -. ref .-> item2
  listItem3 -. ref .-> item3
  listItem4 -. ref .-> item1
  listItem5 -. ref .-> item2

---

For more description, in your case:

cache.put("id", TestClass())
val results = list.getPageFrom(null, null)

// cache has 1 item
// list has 0 items

will be:

flowchart LR
  subgraph cache
    item1["key = 'id'<br/>value = TestClass"]
  end
  subgraph list["list (empty)"]
    empty["(no item in list)"]
  end

---

cache.put("id", TestClass())
list.addKey("id")
cache.put("id", TestClass())
list.addKey("id")

// cache has 1 item
// list has 2 item

will be:

flowchart LR
  subgraph cache
    item1["key = 'id'<br/>value = TestClass"]
  end
  subgraph list
    listItem1["list item 1 (reference to 'item1')"]
    listItem2["list item 2 (reference to 'item1')"]
  end
  listItem1 ==> listItem2
  listItem1 -. ref .-> item1
  listItem2 -. ref .-> item1

---

List should be created directly from kottage.list() that way theres no way to get into weird states and you only interact with the list api. (Would need to add, get(key)/replace(key)/remove(key) to make that useable.

Kottage Cache is KVS, but Kottage List is Linked List, so Kottage List's items cannot be accessed by key. That can be accessed only by page.

• list should be automatically backed by the cache:

Kottage List is not have all items in Cache. The items in cache can be added to list and remove from list in any time.

[valeriyo]

@chrisjenx I think you are asking for the same thing as I -- https://github.com/irgaly/kottage/discussions/254 -- a simple way to get all keys in storage (which is glaringly missing) and attempts to use KottageList for that doesn't quite fit, because:

• duplicate keys are allowed in lists, and

• the double-linked list feature is unnecessarily complex.

  Q: what's preventing getAllKeys method?