pip-services3-commons-node/src/run/Notifier.ts

Portable abstractions and patterns for Pip.Services in Node.js

/** @module run */
/** @hidden */ 
let _ = require('lodash');

import { Parameters } from './Parameters';

/**
 * Helper class that notifies components.
 * 
 * [[INotifiable]]
 */
export class Notifier {
	/**
	 * Notifies specific component.
	 * 
	 * To be notiied components must implement [[INotifiable]] interface.
	 * If they don't the call to this method has no effect.
	 * 
	 * @param correlationId 	(optional) transaction id to trace execution through call chain.
	 * @param component 		the component that is to be notified.
     * @param args              notifiation arguments.
	 * 
	 * @see [[INotifiable]]
	 */
	public static notifyOne(correlationId: string, component: any, args: Parameters): void {
        if (_.isFunction(component.notify))
			component.notify(correlationId, args);
	}

	/**
	 * Notifies multiple components.
	 * 
	 * To be notified components must implement [[INotifiable]] interface.
	 * If they don't the call to this method has no effect.
	 * 
	 * @param correlationId 	(optional) transaction id to trace execution through call chain.
	 * @param components 		a list of components that are to be notified.
     * @param args              notification arguments.
	 * 
	 * @see [[notifyOne]]
	 * @see [[INotifiable]]
	 */
    public static notify(correlationId: string, components: any[], args: Parameters): void {
		if (components == null) return;
		
		for (let index = 0; index < components.length; index++) 
            Notifier.notifyOne(correlationId, components[index], args);
	}
}