cylon/lib/basestar.js

93 lines
2.8 KiB
JavaScript

/*
* basestar
* cylonjs.com
*
* Copyright (c) 2013-2014 The Hybrid Group
* Licensed under the Apache 2.0 license.
*/
"use strict";
var EventEmitter = require("events").EventEmitter;
var Utils = require("./utils");
// Basestar is a base class to be used when writing external Cylon adaptors and
// drivers. It provides some useful base methods and functionality
//
// It also extends EventEmitter, so child classes are capable of emitting events
// for other parts of the system to handle.
var Basestar = module.exports = function Basestar() {
};
Utils.subclass(Basestar, EventEmitter);
// Public: Proxies calls from all methods in the object to a target object
//
// methods - array of methods to proxy
// target - object to proxy methods to
// source - object to proxy methods from
// force - whether or not to overwrite existing method definitions
//
// Returns the klass where the methods have been proxied
Basestar.prototype.proxyMethods = Utils.proxyFunctionsToObject;
// Public: Defines an event handler that proxies events from a source object
// to a target object
//
// opts - object containing options:
// - targetEventName or eventName - event that should be emitted from the
// target
// - target - object to proxy event to
// - source - object to proxy event from
// - sendUpdate - whether or not to send an "update" event
//
// Returns the source
Basestar.prototype.defineEvent = function(opts) {
opts.sendUpdate = opts.sendUpdate || false;
opts.targetEventName = opts.targetEventName || opts.eventName;
opts.source.on(opts.eventName, function() {
var args = arguments.length >= 1 ? [].slice.call(arguments, 0) : [];
args.unshift(opts.targetEventName);
opts.target.emit.apply(opts.target, args);
if (opts.sendUpdate) {
args.unshift("update");
opts.target.emit.apply(opts.target, args);
}
});
return opts.source;
};
// Public: Creates an event handler that proxies events from an adaptor"s
// "connector" (reference to whatever module is actually talking to the hw)
// to the adaptor
//
// opts - hash of opts to be passed to defineEvent()
//
// Returns this.connector
Basestar.prototype.defineAdaptorEvent = function(opts) {
return this._proxyEvents(opts, this.connector, this);
};
// Public: Creates an event handler that proxies events from a driver"s
// connection to the driver
//
// opts - hash of opts to be passed to defineEvent()
//
// Returns this.connection
Basestar.prototype.defineDriverEvent = function(opts) {
return this._proxyEvents(opts, this.connection, this);
};
Basestar.prototype._proxyEvents = function(opts, source, target) {
opts = (typeof opts === "string") ? { eventName: opts } : opts;
opts.source = source;
opts.target = target;
return this.defineEvent(opts);
};