In this series of blog posts we will be building a complete responsive web application using the following tech stack :
1) Spring boot
– Spring MVC web
– Spring Data JPA
– Spring Security
2) Thymeleaf for server side templating
3) Angular JS for client side MVC ( including JS dependency management with bower)
4) Deploy the app on AWS/EBS/Heroku/Openshift
The WordPress.com stats helper monkeys prepared a 2014 annual report for this blog.
Here’s an excerpt:
A New York City subway train holds 1,200 people. This blog was viewed about 7,400 times in 2014. If it were a NYC subway train, it would take about 6 trips to carry that many people.
Today we will try to understand Strategy Pattern with the help of an example.
The example we will consider is The Game of Chess. The intention here is to explain strategy pattern and not to build a comprehensive Chess Game solution.
Strategy Pattern : The Strategy pattern is known as a behavioural pattern – it’s used to manage algorithms, relationships and responsibilities between objects. The main benefit of strategy pattern is to choose the algorithm/behaviour at runtime.
Lets try to understand this by implementing this to design the chess game.
Problem Statement :
We need to build the software for a pizza company who wants to prepare different types of pizzas, e.g Chicken Pizza, Flat Bread, Pepperoni Pizza with Extra Cheese, put add on toppings on it.
Lets try to see which design pattern suits this problem statement and under what scenario.
Traditionally, for pizza problem, builder pattern is most commonly used. However there are some examples using decorator as well, both the approaches are correct but there is difference in use case.
Builder is an object creation pattern whereas decorator is used to change the already built object at runtime.
Lets try to understand this by the examples :
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XStream library can be an effective tool for converting JSON to Java to XML translations to and fro.
Lets explore each one of them one by one, and see which driver is used.
Handling JSONs
To convert JSON to Java objects all you have to do is initialize XStream object with an appropriate driver and you are ready to serialise your objects to (and from) JSON.
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Lets recap what all we have done in the last blog :
1.) Setup workstation and chef-repo.
2.) Registered on chef to use hosted chef as the chef-server.
3.) Bootstrapped a node to be managed by the chef-server.
4.) Downloaded the “apache” cookbook in our chef-repo.
5.) Uploaded the “apache” cookbook to the chef-server.
6.) Added the recipe[apache] in the run-list of the node.
7.) Ran the chef-client on the client to apply the cookbook.
Now lets continue, and try to understand some more concepts around chef and see them in action.
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Below are the first steps in getting started with using chef.
The three main components of chef are :
1.) Work station
This is the developer’s machine will be used to author cookbooks and recipes and upload them to the chef-server using the command line utility called knife.
2.) Chef-Server
This is the main server on which all the cookbooks, roles, policies are uploaded.
3.) Node
This is the instance which would be provisioned by applying the cookbooks uploaded on the chef-server.
So, lets get started:
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Mule is an enterprise service bus (ESB) and integration framework. In Mule, we define flows and sub-flows in order to integrate applications and orchestrate services.These flows contain endpoints to integrate different applications or services. These endpoints can be HTTP, VM, JMS, etc. More details about development in mule can be found here. Below is a sample flow.
In order to write unit test cases for mule flows, mule provides an abstract JUnit test case called org.mule.tck.junit4.FunctionalTestCase that runs Mule inside a test case and manages the lifecycle of the server.More details about can be found here.
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Whenever we move to a new project, or we want to explore a new stack of technologies; we face the problem of environments. Being a developer we generally have a tendency to install everything on our local environment; which many times proves to be a disaster.
Today, modern web applications involve a lot of moving parts, numerous underlying technologies and a lot of complexity.Read More »
Using ENUM and a map could be a neat way to remove conditional logic, like switch cases in our code.
Another approach could be to use State design pattern, but if you don’t want to create many classes and your use case is pretty simple and using ENUM will not involve repetition of logic. Then using this approach might not be a bad option.
Let see an example :
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anirudh bhatnagar 