design-patterns/chain-of-responsibility.html

﻿<!doctype html>
<html lang="en">
	<head>
		<title>JavaScript Patterns</title>
		<meta charset="utf-8">
	</head>
	<body>
		<script>
			/* Title: Chain of responsibility
			 Description: delegates commands to a chain of processing objects
			 */

			var NO_TOPIC = -1;
			var Topic;

			function Handler(s, t) {
				this.successor = s || null;
				this.topic = t || 0;
			}

			Handler.prototype = {
				handle:function () {
					console.log(this.has());
					if (this.successor) {
						this.successor.handle();
					}
					console.log(this.topic);
				},
				has:function () {
					return this.topic != NO_TOPIC;
				}
			};

			var _handle = Handler.prototype.handle;

			var app = new Handler({
				handle:function () {
					console.log('app handle');
				}
			}, 3);

			var dialog = new Handler(app, 1);
			//dialog.handle = function () {
			//if (this.has()) {
			//} else {
			//console.log('dialog handle');
			//_handle.call(this);
			//}
			//}

			var button = new Handler(dialog, 2);
			//button.handle = function () {
			//if (this.has()) {
			//} else {
			//console.log('dialog handle');
			//_handle.call(this);
			//}
			//}

			button.handle();

			// reference
			// https://gist.github.com/1174982
		</script>
	</body>
</html>