07 Jun 2019
In this tutorial I will talk about some retry examples in Spring and how to do it. Retry logic or in other words retry strategies are being used
when an operation is failed and we want to basically retry that operation again by a logic. Most of the software systems are doing external calls, operations etc.
which are dependent on other systems or resources. For example, charging a client by sending a charge request to Stripe, sending a message to Amazon SQS queue which might failed for a short time due to a transitive issue. Instead of, failing the process at the very first try we can basically have a retry strategy to try the current operation multiple times to continue current process without any issue. In Spring, there are multiple ways to define how to retry on some operation.
02 Mar 2015
We have seen how to inject cdi beans by using qualifiers and producers so far. Additionally, every cdi bean has a lifecycle, and we can initialize and prepare to destroy any managed bean by using two common annotations;
@PreDestroy. Methods annotated with these annotations are called bean lifecycle callbacks.
23 Feb 2015
Enums (Enumeration) are introduced as a new reference type in Java 1.5 with a bunch of beneficial features. They consist of fix set of constants (each constant is implicitly labeled as
public static final) which each constant can have a data-set. Lets see the simplest example of an Enum;
16 Feb 2015
In this tutorial we will see how to use producer methods for injecting CDI beans by
@Produces annotation. We will use Weld CDI implementation.
Using producer methods provides a programmatic way to solve disambiguation by using injection
points. We have already seen how to solve disambiguation by using qualifiers in this
As a first step, we will create a disambiguation.
21 Jan 2015
Adapter design pattern is a structural design pattern that provides two unrelated interfaces to work together. The most common illustration about adapter design pattern is sockets from different countries. Well most of us faced with laptop adapter issues when traveling, and looked for appropriate adapter for our laptops. So, by using an adapter we are able to plug our laptop chargers to sockets. Or using a card reader to plug our memory card from our camera to our computer. Thus, we make two unrelated interfaces to work together. The elements of adapter design pattern are Client, Target, Adapter and Adaptee. We can see the Gang of Four definition for ADP, and description of each element of it below;
Convert the interface of class into another interface clients expect.Adapter lets class work together that couldn’t otherwise because of incompatible interfaces.