/
priorityqueue.go
69 lines (56 loc) · 1.13 KB
/
priorityqueue.go
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package processor
import (
"container/heap"
"log"
"time"
)
// We keep a priority queue of user_id to last event
// timestamp from that user
type pqItemT struct {
userID string //userID
lastTS time.Time //last timestamp
index int //index in priority queue
}
type pqT []*pqItemT
func (pq pqT) Len() int { return len(pq) }
func (pq pqT) Less(i, j int) bool {
return pq[i].lastTS.Before(pq[j].lastTS)
}
func (pq pqT) Swap(i, j int) {
pq[i], pq[j] = pq[j], pq[i]
pq[i].index = i
pq[j].index = j
}
func (pq *pqT) Push(x interface{}) {
n := len(*pq)
item := x.(*pqItemT)
item.index = n
*pq = append(*pq, item)
}
func (pq *pqT) Pop() interface{} {
old := *pq
n := len(old)
item := old[n-1]
item.index = -1
*pq = old[0 : n-1]
return item
}
func (pq *pqT) Top() *pqItemT {
item := (*pq)[0]
return item
}
func (pq *pqT) Remove(item *pqItemT) {
heap.Remove(pq, item.index)
}
func (pq *pqT) Update(item *pqItemT, newTS time.Time) {
item.lastTS = newTS
heap.Fix(pq, item.index)
}
func (pq *pqT) Add(item *pqItemT) {
heap.Push(pq, item)
}
func (pq *pqT) Print() {
for _, v := range *pq {
log.Println(v.userID, v.lastTS)
}
}