Operation processor

gistfile1.js

var OperationQueue = Class.extend({
	init: function(){
		Evented.extend(this);
		this._queue = [];
	},

	process: function(operation){
		this._queue.add(operation);
		this.emit("operationAdded");
	},

	find: function(callback){
		this._queue.forEach(function(operation){
			if(callback(operation)) return operation;
		});
	}
});

var OperationBatcher = Class.extend({
	previous: null,

	init: function(queue){
		this._queue = queue;
	},

	pull: function(){
		var operation = this._findNext();
		this.previous = operation;
		return operation;
	},

	_findNext: function() {
		if(!previous) return this._queue.pop();

		this._queue.find(function(operation){
			if(operation.relatedTo(this.previous)) return operation;
		});

		return this._queue.pop();		
	}
});

var OperationProcessor = Class.extend({
	init: function(target, supplier){
		this._target = target;
		this._supplier = supplier;
	},

	onOperationAdded: function(){
		if(!this.currentOperation){
			this.processNext();
		}
	}

	processNext: function(){
		this.currentOperation = this._supplier.pull();
		if(this.currentOperation){
			this._target.transform(operation).then(function(){
				this.currentOperation = null;
				this.processNext();
			});
		}
	}
});

var queue = new OperationQueue();
var batcher = new OperationBatcher(queue);
var processor = new OperationProcessor(targetTransformable, batcher);

queue.on("operationAdded", processor.onOperationAdded);