Java
Everthing related to the Java programming language
Implementing a Java Server Side component for jWebSocket Server for WebSocket interaction with Web Clients
4In a previous post – http://technology.amis.nl/blog/14949/push-based-synchronized-slideshow-web-application-implemented-using-websockets-and-jwebsocket-server-the-open-source-java-websocket-server – I discussed the implementation of the synchronized slideshow application using Web (HTML/JavaScript) clients and jWebSocket as websocket server. In an earlier article, I described the same for the Kaazing WebSocket server – http://technology.amis.nl/blog/14777/push-based-synchronized-slideshow-web-application-implemented-using-websockets-and-kaazing-websocket-gateway – and both stories are (fortunately) fairly similar. In the Kaazing article I also described a Java based Server Side ‘client’ or ‘WebSocket interaction partner’. In the jWebSocket article, that part was missing and in this article I will rectify that.
This article will describe how a Java application can integrate with jWebSocket server – in fact: start the server from within the Java code -and subsequently register listeners that intercept WebSocket communication from other interaction partners such as Web clients. The Java application can also send messages to specific clients or broadcast to all clients. This article More >
Push-based synchronized slideshow web application – implemented using WebSockets and jWebSocket server – the open source Java WebSocket server
2In a recent article, I have introduced jWebSocket – an open source Java based server for WebSocket communication: http://technology.amis.nl/blog/14940/first-steps-with-jwebsocket-open-source-java-framework-for-websockets-installation-and-running-samples. In this article, I have described how to download and install the jWebSocket server and how to get going with running some of the distributed samples.
In another recent article, I looked at the implementation of a slideshow application where multiple web clients are mutually synchronized using WebSocket based communication using the Kaazing commercial Web Socket Gateway: http://technology.amis.nl/blog/14777/push-based-synchronized-slideshow-web-application-implemented-using-websockets-and-kaazing-websocket-gateway.
In this article, I will implement that same Slideshow application as with Kaazing, this time using the jWebSocket server as my underlying WebSocket infrastructure. It turns out that no server side configuration is required for this initial, somewhat naive implementation that does not use a specific channel but simply has all clients of the jWebSocket server participate in the communication. A more advanced set up would More >
First steps with jWebSocket – open source Java framework for WebSockets – installation and running samples
6This month, In have been delving into Push architectures for the Web, looking into WebSockets among several other things. WebSockets, a fairly new standard (!) evolved along with HTML 5, specifies a communication protocol that provides an alternative to classic HTTP communication. WebSocket based interaction has lower overhead and – more importantly – is bi-directional which means that push from server to client is really supported (and not just emulated through poll, long poll or streaming responses as is currently the case in comet push style frameworks).
All modern browsers provide support for the WebSocket specification – meaning they can communicate based on the WebSocket protocol (ws:// and wss:// in addition to http:// and https://) and they implement the WebSocket client side (JavaScript) APIs. These API are well defined – http://dev.w3.org/html5/websockets/ – and seem to be truly standard across all browsers.
The WebSocket server side is at this moment not very well defined. Other than the fact that the communication over ws:// and wss:// should be handled by a server, not much has been decided about the server side of WebSockets. Currently, WebSockets is not supported in More >
First steps with Java Embedding in Oracle SOA Suite 11g BPEL 2.0 – useful API calls
1While preparing for the next session in our internal SOA for Java Professionals training program on BPEL, I revisited the BPEL activity Java Embedding that allows us to enrich a BPEL process with custom, Java based functionality. I tried to determine how best to explain, present and demonstrate this activity to my colleagues. This article is a brief summary of what I will tell them. It may help you to quickly get up to speed with this activity in BPEL using Oracle SOA Suite 11g.
The Java Embedding activity allows us to add activities in a BPEL process in which we can write a Java snippet using standard JDK libraries, the BPEL APIs, custom and 3rd party Java Classes included in JAR files in deployed SCA composites (in SCA-INF/lib directory) and Java Classes and libraries available on the Classpath for the SOA Suite run time (note: through the oracle.soa.ext.jar file in the directory <FMW_HOME>/soa/modules/oracle.soa.ext_11.1.1 we make the resources available at run time; use the ANT script in this directory to add custom classes and JAR-files to the oracle.soa.ext.jar file).
Push based synchronized Slideshow demo application implemented using CometD and jQuery running on Tomcat
2In a string of recent articles, I have discussed downloading, installing and running demos for a number of different tools, frameworks and libraries that support push-style (web) applications in one way or another. I have looked into ‘classic’ comet with Grizzly, Atmosphere and CometD as well as ADF Active Data Service and WebLogic Pub/Sub (Bayeux) Channels. I have also looked to WebSockets with jWebSocket, again Atmosphere and CometD and also with Kaazing. I am now working on a series of articles in which I use each of these frameworks and push infrastructures to implement the same simple push-style application – to see how that goes and to compare the various implementations. The functionality I will be implementing is simple:
- through the web client (HTML 5/javaScript), a user can select an image from a list of ’slides’
- the selection of the image is communicated to the server (background WebSocket based or alternatively regular AJAX)Comet (Bayeux)/Long Poll style)
- the server informs all connected clients about the selected image through a pushed message (background WebSocket based or alternatively Comet (Bayeux)/Long Poll style); these clients all synchronize that slide More >
Get going with Kaazing WebSocket Gateway – HTML5 Edition – installing locally and running demos
2My last few articles on this blog site have all dealt with push architecture and technology in some way. This is an area that I have been investigating into quite bit recently. Part of these investigations had to be of course Kaazing, a specialized commercial offering, specifcally around WebSockets and its application in new HTML 5 application architectures.
Kaazing suggests a new way of implementing multi-tier (web) applications.
Communication between client and back end services happens over WebSockets. The Kaazing Gateway handles all WebSockets communication, turning messages from various back end services based on technologies such RSS, XMPP, JMS into WebSocket events.
Kaazing supports a variety of clients – though HTML 5 (JavaScript) web clients (including those running on mobile devices) are probably the most prominent ones.
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