ActiveMQ example source code file (chat.js)

This example ActiveMQ source code file (chat.js) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - ActiveMQ tags/keywords

The ActiveMQ chat.js source code

/**
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the 'License'); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an 'AS IS' BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

var amq = org.activemq.Amq;

org.activemq.Chat = function() {
	var last = '';

	var user = null;

	var chatTopic = 'topic://CHAT.DEMO';

	var chat, join, joined, phrase, members, username = null;

	var chatHandler = function(message) {
		var type = message.getAttribute('type');
		var from = message.getAttribute('from');

		switch (type) {
			// Incoming chat message
			case 'chat' : {
				var text = message.childNodes[0].data;

				if (from == last) from = '...';
				else {
					last = from;
					from += ':';
				}

				chat.innerHTML += '<span class=\'from\'>' + from + ' ' + text + '
';
				break;
			}

			// Incoming ping request, add the person's name to your list.
			case 'ping' : {
				members.innerHTML += '<span class="member">' + from + '
';
				break;
			}

			// someone new joined the chatroom, clear your list and
			// broadcast your name to all users.
			case 'join' : {
				members.innerHTML = '';
				if (user != null)
					amq.sendMessage(chatTopic, '<message type="ping" from="' + user + '"/>');
				chat.innerHTML += '<span class="alert">' + from + ' has joined the room!
';
				break;
			}

			// Screw you guys, I'm going home...
			// When I (and everyone else) receive a leave message, we broadcast
			// our own names in a ping in order to update everyone's list.
			// todo: Make this more efficient by simply removing the person's name from the list.
			case 'leave': {
				members.innerHTML = '';
				chat.innerHTML += '<span class="alert">' + from + ' has left the room!
';

				// If we are the one that is leaving...
				if (from == user) {
				// switch the input form
					join.className = '';
					joined.className = 'hidden';
					username.focus();

					user = null;
					amq.removeListener('chat', chatTopic);
				}
				if (user != null)
					amq.sendMessage(chatTopic, '<message type="ping" from="' + user + '"/>');
				break;
			}
		}

		chat.scrollTop = chat.scrollHeight - chat.clientHeight;
	};

	var getKeyCode = function (ev) {
		var keyc;
		if (window.event) keyc = window.event.keyCode;
		else keyc = ev.keyCode;
		return keyc;
	};

	var addEvent = function(obj, type, fn) {
		if (obj.addEventListener)
			obj.addEventListener(type, fn, false);
		else if (obj.attachEvent) {
			obj["e"+type+fn] = fn;
			obj[type+fn] = function() { obj["e"+type+fn]( window.event ); }
			obj.attachEvent( "on"+type, obj[type+fn] );
		}
	};

	var initEventHandlers = function() {
		addEvent(username, 'keyup', function(ev) {
			var keyc = getKeyCode(ev);
			if (keyc == 13 || keyc == 10) {
				org.activemq.Chat.join();
				return false;
			}
			return true;
		});

		addEvent(document.getElementById('joinB'), 'click', function() {
			org.activemq.Chat.join();
			return true;
		});

		addEvent(phrase, 'keyup', function(ev) {
			var keyc = getKeyCode(ev);

			if (keyc == 13 || keyc == 10) {
				var text = phrase.value;
				phrase.value = '';
				org.activemq.Chat.chat(text);
				return false;
			}
			return true;
		});

		addEvent(document.getElementById('sendB'), 'click', function() {
			var text = phrase.value;
			phrase.value = '';
			org.activemq.Chat.chat(text);
		});

		addEvent(document.getElementById('leaveB'), 'click', function() {
			org.activemq.Chat.leave();
			return false;
		});
	};

	return {
		join: function() {
			var name = username.value;
			if (name == null || name.length == 0) {
				alert('Please enter a username!');
			} else {
				user = name;

				amq.addListener('chat', chatTopic, chatHandler);
				join.className = 'hidden';
				joined.className = '';
				phrase.focus();

				amq.sendMessage(chatTopic, '<message type="join" from="' + user + '"/>');
			}
		},

		leave: function() {
			amq.sendMessage(chatTopic, '<message type="leave" from="' + user + '"/>');
		},

		chat: function(text) {
			if (text != null && text.length > 0) {
				// TODO more encoding?
				text = text.replace('<', '<');
				text = text.replace('>', '>');

				amq.sendMessage(chatTopic, '<message type="chat" from="' + user + '">' + text + '');
			}
		},

		init: function() {
			join = document.getElementById('join');
			joined = document.getElementById('joined');
			chat = document.getElementById('chat');
			members = document.getElementById('members');
			username = document.getElementById('username');
			phrase = document.getElementById('phrase');

			if (join.className == 'hidden' && joined.className == 'hidden') {
				join.className = '';
				joined.className = 'hidden';
				username.focus();
			}

			initEventHandlers();
		}
	}
}();