README
¶
Priority Queue in Go
====================
This package provides a priority queue implementation and scaffold
interfaces.
Additional to original package, you can enqueue only items which haven't
been already enqueued
Installation
------------
$ go get github.com/mileusna/gopqueue
Usage
-----
Here's trivial example of the fast queue usage:
Hope to post more examples soon
package main
import pqueue "github.com/mileusna/gopqueue"
type Task struct {
Name string
priority int
}
// interface functions for queue items
func (t *Task) Less(other interface{}) bool {
return t.priority < other.(*Task).priority
}
// this should return unique id from struct
// to check weather item has already been into queue
func (t *Task) Id() interface{} {
return t.Name
}
func main() {
q := pqueue.New(0)
q.EnqueueUnique(&Task{"one", 10})
q.EnqueueUnique(&Task{"two", 2})
q.EnqueueUnique(&Task{"three", 5})
q.EnqueueUnique(&Task{"four", 7})
q.EnqueueUnique(&Task{"two", 5})
q.EnqueueUnique(&Task{"two", 6})
q.EnqueueUnique(&Task{"two", 7})
q.EnqueueUnique(&Task{"two", 8})
println(q.Len()) // there will be only 4 items in queue
for i := 0; i < 4; i += 1 {
task := q.Dequeue()
println(task.(*Task).Name)
}
}
// Produces:
// 4
// two
// three
// four
// one
For more information and examples check the package documentation.
Copyright
---------
Copyright (C) 2015 by Milos Mileusnic <milos@groowe.com>
Copyright (C) 2011 by Krzysztof Kowalik <chris@nu7hat.ch>
See COPYING file for details.
Documentation
¶
Overview ¶
This package provides a priority queue implementation and scaffold interfaces.
Addition to original package, this package adds method and other internals for inserting only unique items in queue
Copyright (C) 2015 by Milos Mileusnic <milos@groowe.com>
Copyright (C) 2011 by Krzysztof Kowalik <chris@nu7hat.ch>
Index ¶
- type Queue
- func (q *Queue) ChangeLimit(newLimit int)
- func (q *Queue) ClearHistory()
- func (q *Queue) Dequeue() (item QueueItem)
- func (q *Queue) Enqueue(item QueueItem) (err error)
- func (q *Queue) EnqueueUnique(item QueueItem) (added bool, err error)
- func (q *Queue) IdExists(id interface{}) bool
- func (q *Queue) IsEmpty() bool
- func (q *Queue) ItemExists(item QueueItem) bool
- func (q *Queue) Len() int
- func (q *Queue) RemoveFromHistory(element interface{})
- type QueueItem
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type Queue ¶
type Queue struct {
Limit int
// contains filtered or unexported fields
}
Queue is a threadsafe priority queue exchange. Here's a trivial example of usage:
q := pqueue.New(0)
go func() {
for {
task := q.Dequeue()
println(task.(*CustomTask).Name)
}
}()
for i := 0; i < 100; i := 1 {
task := CustomTask{Name: "foo", priority: rand.Intn(10)}
q.Enqueue(&task)
}
func New ¶
New creates and initializes a new priority queue, taking a limit as a parameter. If 0 given, then queue will be unlimited.
func (*Queue) ChangeLimit ¶
Safely changes enqueued items limit. When limit is set to 0, then queue is unlimited.
func (*Queue) ClearHistory ¶
func (q *Queue) ClearHistory()
Clear queue history so the elements can be EnqueueUnique again
func (*Queue) Dequeue ¶
Dequeue takes an item from the queue. If queue is empty then should block waiting for at least one item.
func (*Queue) EnqueueUnique ¶
Enqueue puts item in queue only if it hasn't already been in queue
func (*Queue) ItemExists ¶
check if item already exists in queue (or it has been into queue)
func (*Queue) RemoveFromHistory ¶
func (q *Queue) RemoveFromHistory(element interface{})
Source Files
Directories