[seam-issues] [JBoss JIRA] (SOLDER-331) @Exact does not do what its name implies/JavaDoc states

[Richard Kennard (JIRA)]

     [ https://issues.jboss.org/browse/SOLDER-331?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Richard Kennard updated SOLDER-331:
-----------------------------------

           Description: 
The Solder annotation @Exact does not do what its name implies/JavaDoc states:

"An injection point qualifier that may be used to select the exact bean to be injected, by specifying its implementation class."

In the test suite it tests:

{{@Inject @Exact(Greyhound.class) private Dog dog;}}

But all @Exact does behind the scenes (in CoreExtension.java) is:

{{if (f.isAnnotationPresent(Exact.class)) { ... builder.overrideFieldType(f, type);}}

So whilst you can make Dog 'exact' into Greyhound, if there exists another class BetterGreyhound:

{{package org.jboss.solder.test.core; public class BetterGreyhound extends Greyhound}}

You *cannot* make BetterGreyhound into Greyhound. If BetterGreyhound exists and you try:

{{@Inject @Exact(Greyhound.class) private Dog dog;}}

You'll get:

WELD-001409 Ambiguous dependencies for type [Greyhound] with qualifiers [@Default] at injection point [[field] @Exact @Inject private org.jboss.solder.test.core.RaceTrack.dog]. Possible dependencies [[Managed Bean [class org.jboss.solder.test.core.Greyhound] with qualifiers [@Any @Default @Named], Managed Bean [class org.jboss.solder.test.core.BetterGreyhound] with qualifiers [@Any @Default @Named]]]

I think @Exact either:

* needs to be a @Qualifier (which it used to be, and which its JavaDoc states it still is); or
* needs to be renamed to @AtLeast; or
* needs its JavaDoc fixed to clarify that it can only resolve ambiguious superclasses, not subclasses


  was:
The Solder annotation @Exact is poorly defined, IMHO, because it does not do what its name implies/JavaDoc states:

"An injection point qualifier that may be used to select the exact bean to be injected, by specifying its implementation class."

In the test suite it tests:

{{@Inject @Exact(Greyhound.class) private Dog dog;}}

But all @Exact does behind the scenes (in CoreExtension.java) is:

{{if (f.isAnnotationPresent(Exact.class)) { ... builder.overrideFieldType(f, type);}}

So whilst you can make Dog 'exact' into Greyhound, if there exists another class BetterGreyhound:

{{package org.jboss.solder.test.core; public class BetterGreyhound extends Greyhound { }}}

You *cannot* make BetterGreyhound into Greyhound. If BetterGreyhound exists and you try:

{{@Inject @Exact(Greyhound.class) private Dog dog;}}

You'll get:

WELD-001409 Ambiguous dependencies for type [Greyhound] with qualifiers [@Default] at injection point [[field] @Exact @Inject private org.jboss.solder.test.core.RaceTrack.dog]. Possible dependencies [[Managed Bean [class org.jboss.solder.test.core.Greyhound] with qualifiers [@Any @Default @Named], Managed Bean [class org.jboss.solder.test.core.BetterGreyhound] with qualifiers [@Any @Default @Named]]]

I think @Exact either:

* needs to be a @Qualifier (which it used to be, and which its JavaDoc states it still is); or
* needs to be renamed to @AtLeast; or
* needs its JavaDoc fixed to clarify that it can only resolve ambiguious superclasses, not subclasses


    Steps to Reproduce: 
Add the following class to the Seam Solder test suite:

{{package org.jboss.solder.test.core; public class BetterGreyhound extends Greyhound}}

Then run 'CoreTest.testExact' and it will fail

  was:
Add the following class to the Seam Solder test suite:

{{package org.jboss.solder.test.core; public class BetterGreyhound extends Greyhound { }}}

Then run 'CoreTest.testExact' and it will fail


    
> @Exact does not do what its name implies/JavaDoc states
> -------------------------------------------------------
>
>                 Key: SOLDER-331
>                 URL: https://issues.jboss.org/browse/SOLDER-331
>             Project: Solder
>          Issue Type: Bug
>          Components: Core
>    Affects Versions: 3.1.0.Final
>            Reporter: Richard Kennard
>
> The Solder annotation @Exact does not do what its name implies/JavaDoc states:
> "An injection point qualifier that may be used to select the exact bean to be injected, by specifying its implementation class."
> In the test suite it tests:
> {{@Inject @Exact(Greyhound.class) private Dog dog;}}
> But all @Exact does behind the scenes (in CoreExtension.java) is:
> {{if (f.isAnnotationPresent(Exact.class)) { ... builder.overrideFieldType(f, type);}}
> So whilst you can make Dog 'exact' into Greyhound, if there exists another class BetterGreyhound:
> {{package org.jboss.solder.test.core; public class BetterGreyhound extends Greyhound}}
> You *cannot* make BetterGreyhound into Greyhound. If BetterGreyhound exists and you try:
> {{@Inject @Exact(Greyhound.class) private Dog dog;}}
> You'll get:
> WELD-001409 Ambiguous dependencies for type [Greyhound] with qualifiers [@Default] at injection point [[field] @Exact @Inject private org.jboss.solder.test.core.RaceTrack.dog]. Possible dependencies [[Managed Bean [class org.jboss.solder.test.core.Greyhound] with qualifiers [@Any @Default @Named], Managed Bean [class org.jboss.solder.test.core.BetterGreyhound] with qualifiers [@Any @Default @Named]]]
> I think @Exact either:
> * needs to be a @Qualifier (which it used to be, and which its JavaDoc states it still is); or
> * needs to be renamed to @AtLeast; or
> * needs its JavaDoc fixed to clarify that it can only resolve ambiguious superclasses, not subclasses

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