functions/io_streams

func_streams.go

package main

import (
	"fmt"
	"time"
	"math/rand"
	"sort"
)


type Entity struct {
	Id	string
	Rank	float64
}

func (e *Entity) String() string {
	return fmt.Sprintf("<Entity: %s, Rank: %v>", e.Id, e.Rank)
}

type EntityList struct {
	Entries		[]*Entity
	Origin		string
	EntryOrder	[]int
}

func (e *EntityList) String() string {
	var entryRepr string
	for _, i := range e.EntryOrder {
		entryRepr += fmt.Sprintf("%v ", *e.Entries[i])
	}
	return fmt.Sprintf("<EntityList: %s>", entryRepr)
}

func NewEntityList(origin string) *EntityList {
	return &EntityList{
		Origin:	origin,
	}
}


func search() chan *Entity {
	ch := make(chan *Entity, 100)
	startTime := time.Now()
	go func() {
		for i := 0; i < 10; i++ {
			res := &Entity{
				Id: fmt.Sprintf("ID_%v", i),
			}
			fmt.Println("found: ", res)
			ch <- res
			time.Sleep(20 * time.Millisecond)
		}
		close(ch)
		fmt.Printf("Searching took: %v\n", time.Since(startTime))
	}()
	return ch
}

func rank(in chan *Entity) chan *Entity {
	out := make(chan *Entity, 100)
	startTime := time.Now()
	go func() {
		for {
			res, open := <-in
			if !open {
				break
			}
			res.Rank = rand.Float64() * 10
			fmt.Println("ranked: ", res)
			time.Sleep(100 * time.Millisecond)
			out <- res
		}
		close(out)
		fmt.Printf("Ranking took: %v\n", time.Since(startTime))
	}()
	return out
}

func getSortedList() (sorted *EntityList) {
	sorted = NewEntityList("SEARCH")

	searchResults := search()
	ranked := rank(searchResults)
	rankMap := make(map[float64]int)
	ranks := []float64{}
	for {
		rankedRes, open := <-ranked
		if !open {
			break
		}
		sorted.Entries = append(sorted.Entries, rankedRes)
		rankMap[rankedRes.Rank] = len(sorted.Entries) - 1
		ranks = append(ranks, rankedRes.Rank)
	}
	fmt.Println(ranks)
	sort.Float64s(ranks)
	fmt.Println(ranks)
	sorted.EntryOrder = make([]int, len(sorted.Entries))
	for n, r := range ranks {
		sorted.EntryOrder[n] = rankMap[r]
	}
	fmt.Println("+++", sorted.EntryOrder)
	return sorted
}

func main() {
	startTime := time.Now()
	results := getSortedList()
	fmt.Printf("Searching,Ranking, Sorting took: %v\n", time.Since(startTime))
	fmt.Println("GOT THIS: ", results)
	fmt.Println("Done.")
}