Wednesday, October 27, 2010

JSON Optimizing for Faster Rendering

All web applications have fast rendering as one of the primary goals, JSON is a preferred choice in most of AJAX based applications because it is lightweight data interchange format.

Consider a scenario where you have to read data from database and render it on UI, typically the steps which will be followed are:

a. Send request data to server using AJAX calls
b. At server end invoke the Business layer
c. Business layer calls the database layer
d. Data returned from database layer is populated into business objects
e. From business objects build JSON objects, send them back to client
f. Client use Javascript libraries to render data on UI.

If everything works fine for you, you can stop reading right now, because you are achieving the required goal in the best way.

But in real world this might not be working for you because of performance issues at one or the other step mentioned above. Here are few performance tips, they might suite in some of the scenarios and might be the worst suggestion in other cases:

1. Store JSON objects in database, read them send them to UI. It will be the fastest Way but how to query, we need to build JSON object from our business objects before sending them to UI.

2. Store JSON objects in one of the columns in database, query on other columns and return the column containing the JSON Object.

These tips might be useful in some of the scenario's, also use JSON API's to add methods to generate JSON objects out of Java Objects.

Hope they might help you, might not help some of you.

Good Luck for faster UI's

Friday, October 22, 2010

Drools - An overview

For Java based applications the most challenging part has always been the business logic maintenance, and pick any applications which you find complex and if we ask ourself how complex it would be moving forward, the answer will always be nX times.

What do we do ? Drools comes for Rescue as a Rule Engine.

Drools provides mechanism:

a. To write business logic in simple english language
b. Easy to maintain and very simple to extend
c. Reusability of logic by defining keywords in a DSL file and using them in DSLR file.

But be careful nothing comes free, everything takes cost in terms of memory and time space.

Use Drools if you really have :

a. Business logic which you think is getting cluttered with multiple if conditions because of variety of scenarios
b. You will have growing demand of increase in the complexity
c. The business logic changes would be frequent (1 - 2 times a year would also be frequent)
d. Your server's have enough of memory as it is a memory hungary tool, it provides performance at cost of memory

Choosing a technology stack is a big decision for the lifecycle of an application, so evaluate both pros and cons and if they fits in your application requirements go for it because it is one of the easiest to use and plug in Java based Rule Engine.

Some programmers might find it cumbersome as we are used to looking at the code which is being executed and loves to debug it and understand it and see what is actually happening, latest version of Drools 5.0 address this by providing JMX support and functionality to see the generated Java Code.

Good Luck with your Rule Engine !!

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