We Keep Coding

LDAP Server front-end Java library

I've been asked to look into adding an LDAP interface to an existing Java web application - that is, to make it possible for LDAP clients to connect to the application as if it's an LDAP server. I could write code to listen on a dedicated port and implement the LDAP protocol, and hook that into the existing database... but I'd have to understand the protocol first and then there are potential security issues if I write that from the ground up (not to mention the time it could take).
What I'm looking for is a library of existing code - something that handles the ports and protocols, and lets me focus on writing just the back end. There are plenty of client-side libraries out there, as you'd expect, but I've had no luck in finding something to help with server-side development. So the question is, does anyone here know of such a library that would help with this?

Yes you will most probably find many more client implementations than server, however LDAP is a request response protocol, so with a bit of playing around you should be able to use the same classes and their serialization capabilities. Instead of sending the request you would be receiving it, and responding with the response you would otherwise expect from the client.
You could look at the Apache Directory. https://directory.apache.org/api/
It has an embedded directory server project as part of it, which claims to be extensible and embeddable in your application. https://directory.apache.org/apacheds/
So maybe that could be the answer to your needs.

Creating Java Client for CMIS-based server

I am still new in CMIS subject , and I am still searching learn about that, What I want to do is to create a Java client that upload report to any content management that support "The CMIS v1.0 OASIS Standard Specification". such as Alfresco , Documentum or Microsoft SharePoint Server I found that opencMIS for Java is a good choice ..
But I am still a bit confused about what is required to write such application the communicate with these CMSs ans repositories .
Do I need to handle each one alone , or to create it once and it
will deal with any CMSs that support this standards ?
How the CMIS client will connect to the CMIS-based server. Do we will have authentication data and a communcation endpoint(URL)?
Please if possible-briefly- what are the steps required to do to make a CMIS client using OpenCMIS, does it a hard work for who don't have any previous experience in this topic on has a knowledge about xml, http ..etc?
Thanks in advance

OpenCMIS is really there to let you abstract from the low level protocol details such as XML payloads and the like. On the other hand, it's highly advisable to get a grasp of the protocol itself, just to know what's possible and what not, when designing your application.
Also, the idea behind CMIS is that the same library can access all the compliant CMSs without any code change. What happens in reality is that vendors might have specific extensions that might not be fully portable, and your application might need reworking to support a new CMS (Alfresco aspects are a good example).
The page linked by #Romain Hippeau is providing a number of examples of the OpenCMIS client API usage.

How can I make my J2EE web application work offline?

I want to make my web application able to work offline and as soon as it becomes online or gets connected again, then it should be able to transfer the modifications made by user in offline mode.
I have seen Google Gears as an ideal solution for my problem, which is not recommended to be used as it is now deprecated.
What is a good way to make my application work offline, both in terms of technology to use and application design?

Gears is deprecated because the HTML5 standard allows for equivalent features to be present in compliant browsers.
With respect to your current problem at hand of handling offline web application access, you can look into the support offered by HTML5 for offline web applications via support for client-side SQL database access, and the client-side application HTTP cache.
The features will have to be used in conjunction, as the client-side database access will allow for storage of data (generated when the application is offline) in a structured format, while the offline application cache will allow for caching of HTTP responses from the server; you should not be caching responses that are dynamic in nature which depend on any user-provided inputs.
The details of the proposed APIs can be found in the W3C HTML5 specification, which is in draft at the moment, although it appears that certain user-agents have already implemented this feature.

Firstly, you will need some form of offline storage. HTML5's capabilities are the successor to Google Gears, as stated on the google gears developer blog; essentially, the purpose of Google Gears was just to push the development & subsequent adoption of HTML 5 features.
Specifically you should be looking at the HTML5 offline (here's a tutorial) APIs, and the Storage APIs may also come in handy (relevant tutorial).
With regards to design, you will essentially need to maintain your complete web application state client side, and then send over the differences (i.e. update the server-side state) as soon as the connection to the server is available again.
Off the top of my head, there's 2 simple ways to design this:
Explicitly maintain separate application states for the client and server. Essentially, when the user takes an action, it's applied to the client application state first, and then at specified intervals (and/or triggers, e.g. the user clicks the save button), the client sends over the differences between the last known state of the server and the current state of the client. This is probably best suited to highly interactive web applications, and I suspect Google Docs works on this kind of design. Depending on your application (if "conflicting changes" can occur), you'll need to also account for merging application state: do you override with the last received client state, or do you intelligently try to merge? (you'll have to decide which makes more sense for your particular application.)
Record user actions while offline, and replay them once the connection becomes available again. You essentially implement the Command design pattern, and have both your client-side code and server-side code able to handle each command. The client-side code always handles each command, and while the connection to the server is available, your client side code also sends off the commands to the server. You'll probably want to implement some batching, to avoid continual requests to the server, and also some roll-back functionality when requests to the server fail (e.g. conflicting changes). This ends up looking more or less like GMail's main email managment user interface, where you can undo operations.

This has not much to do with J2EE, but rather how you code your web-client. One possible solution would be to use a javascript client that does save the data in the local storage introduced with html5 (see http://diveintohtml5.ep.io/storage.html ). That is also basically the reason why google gears was stopped ...

Live propagation of DataGrid / ArrayCollection when changing values in Flex application

I've seen a bunch of screencasts demonstrating the integration between blazeds and flex, also some lcds tutorials, model driven or not.
I've seen that some of them the presenter opens 2 browsers and once you change one value in a grid, it propagates to all other grids that presents the data.
I am wondering how the heck this is done, and how to reproduce.
Does this feature depends of the Edge / LCDS solution? I don't think so, but I've never seen some code explaining about it.
I feel it may or may not rely on JMS / MQ / messaging protocols or if this is some sort of 2 way sync and propagation of collection between instances of the same service result.
Thanks for any inputs.
Cheers,
Ernani

You can implement this feature both with BlazeDS and LiveCycle Data Services. BlazeDS provides remote and messaging features (the messaging features is the one allowing you to synchronize the data between the clients), LCDS extends BlazeDS adding new features like data management (productivity improvements), PDF generation, EDGE server for dealing with DMZ zones), MDA development, portal integration etc. It also adds some advanced messaging features like message conflation, throttling, reliability.
BlazeDS is free and open source and in my opinion a robust solution, you can use it if you want to synchronize the data between clients. LCDS adds a lot of things, but the LCDS customers should have a large budget.
How does it work? There is no JMS behind for this feature (however BlazeDS can integrate with a JMS provider so you can have one client in broswser and the second one running a SWING application). Instead there are some message queues on the server and a publisher - subscriber graph. In order to push the data from the clients to the server there are several choices, the more advanced are available only on LCDS: HTTP polling, HTTP long polling, HTTP streaming, RTMP sockets (LCDS only). All of them are described in details on Damon blog.
If you want to see some code go and download BlazeDS and take a look on the samples, there are several ones showing the messaging features. Also there a tomcat server is bundled in the download, and the samples are already deployed in it.

To do this you need to keep an open socket connection between the client and the server so that the server can push data back to the client.
I believe that the RTMP protocol was used for this two-way communication.
I understand that this is the primary reason to use LiveCycle Data Services over BlazeDS. WebORB also has push functionality, as does GraniteDS. I've also seen demos where this is done with ColdFusion.
If none of those options are available to you, you're stuck doing some kind of polling to the remote server.
Unfortunately, I do not have specific code samples to share.

A simple sample showing how to do this using WebORB can be found here:
http://www.kensodev.com/2009/11/01/synchronize-client-application-using-flexweborb-net/
That sample is based on WebORB 3 for .NET; WebORB 4 is now available, for both .NET and Java.
Point being: This is brain-dead simple using WebORB, which is FREE (although a paid Enterprise version is also available). God forbid that anyone should shell out $30K for LCDS just to get this feature.
--- Jim Plamondon, Midnight Coders (makers of WebORB)

Microsoft Reporting Services WebServices and Java

Has anyone successfully implemented a Java based solution that uses Microsoft SQL Server 2005 Reporting Services? Reporting Services comes with a set of Web Services that allow you to control the creation of a report, execution of a report, etc and I am just starting development on a POC of this integration. A couple of choices I have yet to make is whether I want to use Axis2 for the wsdl-to-java functionality or use WebLogic's clientgen (wsdl 2 java) solution. I guess I can also use JAX-WS and wsimport. Before I dive into this, I wanted to see if anyone was doing this successfully with one of the many options available.
In the past, I've had a few issues on how null/blank/empty's are handled between .NET and Java web-services and I just wanted to see if this had come up as an issue with SSRS and Java integration. Thanks

My experience with RS would lead me to suggest you go with just about anything else. I think the web services portion would work fine but I'd be concerned about how RS manages memory and how many reports you need to be running at once before making any decisions. I'm fighting with memory management problems today with RS and even on top of the line hardware it's hard to run large reports (large number of rows returned and a wide result set).
That being said if you think RS can handle your usage then it might be good. The development environment is sort of nice and it's easy to understand and lay out reports. The table layout paradigm it has is pretty good.

I just wanted to come back and answer my own question. I started with Axis2, Apache's implementation of SOAP. After generating the client using WSDL2Java, I was able to successfully invoke Microsoft Reporting Services WebService and generate reports, output in Excel, PDF, CSV and other formats. In my case, I also used Axis2 or HttpClient's NTML authentication mechanism to have my application automatically 'log-in' using credentials from Active Directory and generate and distribute reports to many users.

we've successfully implemented that: JBoss 5 -> IIS proxy -> MS Reporting Services 2008 (via webservice).
There are few pitfalls: MS RS 2008 does not support 'Anonymous' access anymore (2005 does), and does enforce using NTLM authentication. That is still a challenge in Java world, there is no good NTLM library available.
To overcome that, we've implemented trivial proxy (IIS7 + ashx) that does NTLM authentication on RS (user/password hardcoded) and allows Anonymous access for JBoss (by simply rewriting http response).
Works ok :)
Cheers
P