Access operation

access.scala

def access(key: UUID): Int = {
    val tmp = this.byKey(key)
    if (tmp == null) {
      throw new Exception("No such key")
    }

    val freq = tmp.parent
    var nextFreq = freq.next

    if (nextFreq == this.frequencyHead || nextFreq.value != (freq.value + 1)) {
      nextFreq = LfuCache.getNewNode(freq, nextFreq, freq.value + 1)
    }

    nextFreq.items += this.byKey(key)
    tmp.parent = nextFreq

    nextFreq.prev.items -= nextFreq.prev.items.filter(freq => freq.key == key).head
    if (nextFreq.prev.items.isEmpty){
      this.deleteNode(freq)
    }

    tmp.data
}