@Service @Lazy //changes the moment when the bean instance is created ///will not display the actions in postconstruct and predestroy, the context is created and closed //PostConstruct and PreDistroy can also be called directly but this is not compliant to Spring standards //more ofther these methods are marked as private so that they should not …
The java developer can use 2 standard Java annotations to interwine in a bean lifecycle inside a Spring context These annotations are used by ejb, jpa, spring, jsf contexts . @Postconstruct – used for any initialisation In not advisable to give values in a Bean constructor There is a chance that the Postconstructor should not …
@Qualifier @Target(ElementType.FIELD,ElementType.CONSTRUCTOR,ElementType.METHOD,ElementType.TYPE) @Retention(RetentionPolicy.RUNTIME) /*Another way to use @Qualifier is to declare an annotation Target must declare type, method, constructor and field to be succesfuly recognized as annotation The java developer needs to declare retention policy runtime to be detected with by the Java Reflection mecanism this annotation can be used to replace @qualifier(bean name) */ …
Let’s create a package service and define an interface called IMyService This Java interface will contain all the methods that a service can be able to offer In a memory zone such as IMyService (interface) we can add memory zones of type MyServiceA through polymorphism To identify this class the java coder will implement the …
@Qualifier annotation in Spring To exemplify the use of @Qualifier annotation we should define an abstractisation of a bean Often the bean is abstracted and we should represent the bean through abstractisation not through a direct implementation Using a concret type of variable is not advisible to be used to indejected in an instance dependency …
How to parse a json that is the response from a call to an Endpoint in Java Let’s assume we have the following response: { “took”: 4, “timed_out”: false, “_shards”: { “total”: 5, “successful”: 5, “failed”: 0 }, “hits”: { “total”: 2, “max_score”: 1, “hits”: [ { “_index”: “event1_201708”, “_type”: “banner_event”, …
How to use the Mediator class, an example: public void useMediator(int banner_id, String banner_user){ BodySource bodySource = new BodyRequestMediator(banner_id, banner_user).setBody(); //at this point we have constructed a whole object that is able to represent our desired json schema presented before as a body and indirectly called the constructor with 2 arguments in class Term: public …
First Level Class – let’s call it BodySource – this will be the class that will be send with @Body annotation along with the PUT request This class should be further be constructed using its inner nodes represented as classed. Also a Builder design pattern is recommended to be used @JsonInclude(JsonInclude.Include.NON_NULL) @JsonPropertyOrder({ "query" }) public …