Enterprise Java

Load inheritance tree into List by Spring

I noticed interesting Spring feature. One of my colleagues used it for loading whole inheritance tree of Spring beans into list. Missed that when I was studying Spring docs.

Let’s have this inheritance tree of Spring beans:

 
 
 
 
 
 
animals-class-diagram

In following snippet is this tree of beans loaded into list with constructor injection:

@Component
public class Nature {
	List<Animal> animals;

	@Autowired
	public Nature(List<Animal> animals) {
		this.animals = animals;
	}

	public void showAnimals() {
		animals.forEach(animal -> System.out.println(animal));
	}
}

Method showAnimals is using Java 8 lambda expression to output loaded beans into console. You would find a lot of reading about this new Java 8 feature these days.

Spring context is loaded by this main class:

public class Main {
	public static void main(String[] args) {
		AnnotationConfigApplicationContext context =
				new AnnotationConfigApplicationContext(SpringContext.class);

		Nature nature = context.getBean(Nature.class);
		nature.showAnimals();
	}
}

Console output:

PolarBear []
Wolf []
Animal []
Grizzly []
Bear []

Lubos Krnac

Lubos is a Java/JavaScript developer/Tech Lead and Automation enthusiast. His religion is to constantly improve his developments skills and learn new approaches. He believes TDD drives better design and nicely decoupled code. Past experience includes C++, Assembler and C#.
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Tomasz N.
9 years ago

Use method references:

animals.forEach(System.out::println);

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