Queues - bali-nebula/go-component-framework GitHub Wiki

Overview

A queue is a collection that supports first-in-first-out (FIFO) semantics. Each value in the queue is a component. Queues allow multi-threaded access.

A Quick Example

To whet your appetite, here is some short example code that demonstrates the behavior of queues.

package main

import (
	fmt "fmt"
	syn "sync"
	abs "github.com/bali-nebula/go-component-framework/v2/abstractions"
	bal "github.com/bali-nebula/go-component-framework/v2/bali"
)

func main() {
	// Create a new queue from a string containing Bali Document Notation™.
	var queue = bal.Queue(`[
    "first"
    "second"
    "third"
]($type: /bali/types/collections/Queue/v1)`)
	fmt.Println("The initial queue:", bal.FormatEntity(queue))

	// Create a wait group for synchronization.
	var wg = new(syn.WaitGroup)
	defer wg.Wait()

	// Add another value to the queue.
	queue.AddValue(bal.Component(`"fourth"`))
	fmt.Println("The augmented queue:", bal.FormatEntity(queue))

	// Remove values from the queue in the background.
	wg.Add(1)
	go func() {
		defer wg.Done()
		var value abs.ComponentLike
		value, _ = queue.RemoveHead()
		fmt.Println("The first item from the queue:", bal.FormatComponent(value))
		value, _ = queue.RemoveHead()
		fmt.Println("The second item from the queue:", bal.FormatComponent(value))
		value, _ = queue.RemoveHead()
		fmt.Println("The third item from the queue:", bal.FormatComponent(value))
		value, _ = queue.RemoveHead()
		fmt.Println("The fourth item from the queue:", bal.FormatComponent(value))
		value, _ = queue.RemoveHead()
		fmt.Println("The fifth item from the queue:", bal.FormatComponent(value))
		fmt.Println("The queue is now empty:", bal.FormatEntity(queue))
	}()

	// Add one more value to the queue.
	queue.AddValue(bal.Component(`"fifth"`))
	queue.CloseQueue()
	fmt.Println("The current queue:", bal.FormatEntity(queue))
}