Decisions Vs 'Informed' Decisions

 

How do we take decisions on technology choice ? Not only technology applies to other decisions we take.Do we really list down the tradeoffs before going with decision X with decision Y ?

Recently I had discussion with two my my customers on chosing a portal server. During both the disucssions I felt, the discussion of what portal server should i uses was premature.

For of Portal based applications, before even thinking about which portal server to use, first question I think should be

1. What do I really need, is it a ‘Portal’ or a just ‘Mashup’ which could be done with even normal web application with HTML5 CSS3.

List down the tradeoffs , “ What I gain if I develop as portal and what I lose if not “.

2. Came down to portal ? Now what kind of portal I’m trying to build

a. Is it a Content Management Portal ? Where you allow users to add, edit, publish, version contents. Workflows could also be involved here

b. Is it Content ‘Centric’ Portal? Where you pull information from different sources

c. Is it a Application Centric Portal? Where you users to access different application with a Single-Sign on

d. Is it a Information Portal ? Mashups with RSS feeds, stock charts, weather etc

e. Is it targeted for specific audience, like say travel information ? or it brings information aimed at all type of users like rediff, yahoo etc

There is difference in approach to be taken for each type of portals.

3. After deciding on the kind of portal I need to build, think how much ‘social’ and ‘collaboration’ I need for my portal users like Wiki, Blog, instant messaging etc. Do I need them, some of them or none ?

If include ‘social’ feature in my portal what I’m gaining , If I don’t what I’m losing?

Now I’m are more clear on my expectations from a Portal Server. So what all I need , Content Management , Security, Integration , Collaboration etc. ?

With the expectations clear , ask one more questions ,

Do I need open source or enterprise ? what I’m gaining for Open Source choice and what I’m losing?

Ok, I decided go with open source market, which one to chose from. But since I decided earlier what I should need from a Portal Server, my decision is much easier.

If confused, I’ll put the choices before me and I need to ask again, If I chose this “What I lose and what I gain”.

I didn’t started expecting write on portal, recently I read some article on decision making. So I was trying think through it. But I ended up in writing a technical post ?

So to summarize, are we making ‘decisions’ or ‘informed’ decisions ?

Any thoughts?

Apache Camel - Spring

Though Apache Camel come with lot of examples , when I was totally new to Camel I found it a bit difficult to follow. I couldn't find a simple example to get me started in google as well. Here is a simple Camel-Spring example.


Before we start, 


What is Camel?
Apache Camel is an Open Source Integration Framework based on known Enterprise Integration Patterns


Need for Camel,


For Integrating Systems , you have few options like,


Option 1, Develop a custom solution. This Works & Fastest for small use cases
Option 2, Use Integration framework.


Cons,

• Framework do the heavy lifting
• Focus on business problem
• Not "reinventing the wheel“

Option 3, Enterprise Service Bus. But ESB's are more than a integration framework, many uses may not need that complexity.


Since you are here, I assume , you have decided to go with Option 2. Camel won't disaapoint you. Now Let's get our hands dirty,


What all you need?


1. apache-activemq , Download here
2. apache-camel


What are we trying to do?


Very simple scenario, I need to read from a message queue and save the message to file. [You may never face such a use case but, good enough to explain the concepts]




(Step 1) Set Java Home and the Java path
(Step 2) Set Up Your Queue

• Unzip apache-activemq
• For windows, go to apache-activemq-5.5.1\bin\win32
• Run activemq.bat
• Once the mq is started, go to http://localhost:8161/
• On the home page, click on Manage ActiveMQ broker
• One the page opened you will find a link "Queues", Clictk on "Queues"
• Give a name, say IN_QUEUE, for your queue in the text box. Click "Create"

Now you test message queue is ready.


Before we go further, there are few things in Camel, you should know,


Camel consists of a CamelContext which contains a collection of Component instances.


Components are the extension point in Camel to add connectivity to other systems. Endpoint where the message comes in or leaves the integration layer. Acts rather like a URI or URL in a web application or a Destination in a JMS system; you can communicate with an endpoint "c:/tmp", you could use URIs like "jms:aQueue" and "file:c:\tmp .


Processors are used to manipulate and mediate messages in between Endpoints. The Processor interface is used to implement consumers of message exchanges or to implement a Message Translator.


To wire Processors and Endpoints together, Camel defines a DSL Camel provides Java DSL, Spring XML, Scala etc.


We trying implement this use case with Camle Spring support.


So we leave few things to Spring like create the Camel Context, Define your Compoent.Now in this use case we have two Component, a JMS component and File Component.


Step 3 [As precondition, you need to create the Java Project in you IDE and add required the jar files to the build path]




(a) Create spring-demo.xml

(b) Create a class which extends RouteBuilder, This is where you configure your 'Route'. Route connects Components through the Endpoints. Routes are defined using DSL. Here we use Java DSL


@Override
public void configure() throws Exception {
from("jms:queue:IN_QUEUE").
to("file://D:/Work/My Workspace/Camel/springout");
}




The code says get message 'from' IN_QUEUE and transfer 'to' a file. Now how do you test this code ?


For that you need some one to put messages to your IN_QUEUE. Let's write one the Camel way. I created another xml , to create a new Camel Context. Basically I wanted the client to be used else where.


Here is my client-spring.xml

This is my Client code,

Now for the test,


First run the server or the class which extends RoutBuilder


java -duration 60s -fa /META-INF/spring/spring-demo.xml


This will keep the server live and keep looking for messages.Now just run the Client code to put the message.You should see the file created in the out put folder.

Evolving Architecture ...

Recently I heard some one using the term 'Evolving Architecture'...

I'm wondering how much an architecture can 'evolve'. If architecture can evolve, then how much 'architecture' should be there in the beginning ?

During the days of water fall projects , we had the fully signed off (no really though ;o) ) architecture before we start anything. But now in the days of iterative development , this may not the be case.

So should we allow the architecture to 'evolve' or create a full blown architecture before we start ?

I think it should be some where in between !!!

There are some decisions we should not defer, till we run into problems..

Identify the architecturally significant pieces and create structure and strong foundation for those in the beginning..

If you are deferring something for later..be sure you are aware of the consequences..

Any thoughts ?

Huh!! ..I'm not needed anymore

Yes I'm talking about the role of a 'architect'.

Most of the projects after few iterations/releases I start to feel I’m unnecessary in that project. I used to get frustrated and always been in ‘confused’ state.

But now a days I start thinking like, maybe there is nothing wrong to be in that state of being ‘unnecessary’ in a project.

Doesn’t that indicate I had done might have done my job well ? Had laid out the foundation for the development team to build the structure. Has defined the process/standards/check lists for them.

Project managers are at ease now. I had developed healthy relationship with the team members and communicated the concepts well enough and they don’t need me anymore.

So being ‘unnecessary’ in a team can be a good thing at times.

Any thoughts ? :o)

Video Preview Portlet-Liferay Alfresco Integration

Video Preview Portlet can be implemented in couple of ways.

In my scenario, I had to pull the video content from Alfresco and show the preview inside a portlet.

Kept it simple using JQueryMedia Plug-in.

Steps

1. Copy the JQuery Media Plugin scripts to your web application or if you have a theme, then to the theme folder.

2. Include scripts in the jsp page or the velocity template (in case of Portlet theme)

3. Add the below code in jsp

<script type="text/javascript">
$(function() {

$('a.media').media();

});

</script>

4. To show the video preview add

<a class="media {width:480, height:280}" href=" <YOUR URL HERE >" >VIDEO </a >

Inside href, you need to give the URL for the video. To get the URL need to use the Alfresco API.

Based on the file tye (the JQuery checks for extension) the library will embed the plug-in for the player in the web page.

Ex, if its wmv it will embed Windows Media Player, for flv , flash player, mov ,Qucik time (if available on your browser, else it will ask to download)

Spring SimpleMappingExceptionResolver to log stack trace

SimpleMappingExceptionResolver is generally used to redirect to an error page. It can be extended to log the trace to a log file.

public class LoggingExceptionResolver extends SimpleMappingExceptionResolver {

private static Log log = LogFactory.getLog(LoggingExceptionResolver.class);

public LoggingExceptionResolver() {
super();
}

@Override
public ModelAndView resolveException(HttpServletRequest request,
HttpServletResponse response, Object handler, Exception ex) {
log.debug(getStackTrace(ex));
return super.resolveException(request, response, handler, ex);
}

/**
* @param t , Throwable
* @return String of the exception
*/
public String getStackTrace(Throwable t) {
StringWriter stringWritter = new StringWriter();
PrintWriter printWritter = new PrintWriter(stringWritter, true);
t.printStackTrace(printWritter);
printWritter.flush();
stringWritter.flush();
return stringWritter.toString();
}
}

Configure this bean,
< bean id="exceptionResolver" class="com.common.service.LoggingExceptionResolver" >
</bean >

Binary Data Over REST Web Service

There was requiremnet to retrieve images from a Content Management System and render the content to a portlet deployed in Liferay.

The application was built on top of Spring MVC portlet and the Service calls from Portlet was REST API calls. So the REST WS API was made to return a byte[] of the content

To sent binary data in REST call [senting binary over REST WS may be questioned], you should encode using sun.misc.BASE64Encoder and on the receiving end you can use sun.misc.BASE64Decoder to decode the data.

The code looks like this

Service API

@RequestMapping(value = "/cms/image", method = RequestMethod.GET)
public void (ModelMap modelMap){
byte[] buff= getBytes(); // Return the byte[] of the image
String imgaeArray= new sun.misc.BASE64Encoder().encode(buff);
modelMap.addAttribute("result", imgaeArray);
}

At Portlet end;

@Autowired
RESTRepository repository;

@RequestMapping(params = "action=preview")
public String preview(Model model, RenderRequest renderRequest,RenderResponse renderResponse) {
Map <String, Object> paramMap = new HashMap<String, Object>();
Map <String, String> map = repository.get("/cms/image", Map.class,paramMap);
byte [] imgaeArray= new sun.misc.BASE64Decoder().decodeBuffer(map.get("result"));

}

If you don't know the content type, then you may need to return a DTO in the REST API instead of just encoded byte[] . DTO can have the properties to hold the byte[] and the content type.