By Golang

// Package queue creates a ItemQueue data structure for the Item type
package queue
import (
    "sync"
)
// Item the type of the queue
type Item interface{}
// ItemQueue the queue of Items
type ItemQueue struct {
    items []Item
    lock  sync.RWMutex
}
// New creates a new ItemQueue
func (s *ItemQueue) New() *ItemQueue {
    s.lock.Lock()
    s.items = []Item{}
    s.lock.Unlock()
    return s
}
// Enqueue adds an Item to the end of the queue
func (s *ItemQueue) Enqueue(t Item) {
    s.lock.Lock()
    s.items = append(s.items, t)
    s.lock.Unlock()
}
// Dequeue removes an Item from the start of the queue
func (s *ItemQueue) Dequeue() *Item {
    s.lock.Lock()
    item := s.items[0]
    s.items = s.items[1:len(s.items)]
    s.lock.Unlock()
    return &item
}
// Front returns the item next in the queue, without removing it
func (s *ItemQueue) Front() *Item {
    s.lock.RLock()
    item := s.items[0]
    s.lock.RUnlock()
    return &item
}
// IsEmpty returns true if the queue is empty
func (s *ItemQueue) IsEmpty() bool {
    s.lock.RLock()
    defer s.lock.RUnlock()
    return len(s.items) == 0
}
// Size returns the number of Items in the queue
func (s *ItemQueue) Size() int {
    s.lock.RLock()
    defer s.lock.RUnlock()
    return len(s.items)
}