[jira] [Created] (ARIES-2027) CDI of java.util.Set and order of org.ietf.jgss.Oid

["Peter Rader (Jira)" <ji...@apache.org>]

Peter Rader created ARIES-2027:
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             Summary: CDI of java.util.Set and order of org.ietf.jgss.Oid
                 Key: ARIES-2027
                 URL: https://issues.apache.org/jira/browse/ARIES-2027
             Project: Aries
          Issue Type: New Feature
          Components: CDI
    Affects Versions: cdi-1.1.3
            Reporter: Peter Rader


TL;DR

CDI in Aries allowes only one-bean-injection. CDI in Aries should allow flexible-bean-amount-injection using java.util.Set.

 

Long:

Since karaf show the [example of CDI using Aries|https://github.com/apache/karaf/blob/29d02c282acb370cca18535ad9a6bbbb0823b1de/examples/karaf-cdi-example/karaf-cdi-example-consumer/src/main/java/org/apache/karaf/examples/cdi/consumer/MyConsumerBean.java#L31] there is a feature missing that is implemented in other CDI containers like SpringCDI: The possibility of inject multiple beans into one field.

Currently the field in the example is written like this:
{code:java}
    @Reference
    @Inject
    private MyServiceBean service;
{code}
Unfortunately the MyServiceBean is a concretation and a dependency. Since the dependency-inversion-principle (DIP) points out: "Entities must depend on abstractions, not on concretions.". This example is concrete-dependency because:
 # We are strict to use only-one implementation of a bean.
 # It is not possible to have no implementation (optional) of the bean.

h3. Why we should not allow other collection-types?

We have other candidates for collection types.
 # Arrays
They are impractical because we can not use the keyword final as the access-modifiers of the instances because final on a array is only finalizing the size of the array. You could modify the array using java-code what is error prone.
 # java.util.List
They are impractical because a List might contain the same instance multiple times what allowes a unexpected ambiguity. Since the CDI-Container is the only authority who creates the instances, we can eliminate this unexpected ambiguity.
 # javax.swing.TreeNode
Its not part of the core-jdk, it might require Compact-Profiles.

By the way: Latter a Springs Ordered-pendant is requested to order the set-elements, but using org.ietf.jgss.Oid instead of a number. 



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