private boolean setAndConnect(URL url, IOCallback callback) {
		if(this.connection != null)
			throw new RuntimeException("You can connect your SocketIO instance only once. Use a fresh instance instead.");
		if ((this.url != null && url != null)
				|| (this.callback != null && callback != null))
			return false;
		if (url != null) {
			this.url = url;
		}
		if (callback != null) {
			this.callback = callback;
		}
		if (this.callback != null && this.url != null) {
			final String origin = this.url.getProtocol() + "://"
					+ this.url.getAuthority();
			this.namespace = this.url.getPath();
			if (this.namespace.equals("/")) {
				this.namespace = "";
			}
			this.connection = IOConnection.register(origin, this);
			return true;
		}
		return false;
	}
Sets url and callback and initiates connecting if both are present

@param url
           the url
@param callback
           the callback
@return true if connecting has been initiated, false if not
src/io/socket/SocketIO.java