BUG: Brooklyn Entities can't be used with a normal javac

[pveentjer]

When I use a normal javac to compile a completely ordinary entity, I get the following error:

[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.0:compile (default-compile) on project brooklyn-social-apps: Compilation failure [ERROR] /Users/alarmnummer/Java/Projects/Cloudsoft/brooklyn-social-apps/src/main/java/io/cloudsoft/socialapps/drupal/Drupal.java:[15,8] brooklyn.entity.rebind.Rebindable cannot be inherited with different arguments: <> and

When I enable the groovy compiler in the pom.xml, the error is gone.

The entity:

public class Drupal extends SoftwareProcessEntity {

... here were a lot of config keys

public Drupal(Map flags) {
    this(flags, null);
}

public Drupal(Entity owner) {
    this(new LinkedHashMap(), owner);
}

public Drupal(Map flags, Entity owner) {
    super(flags, owner);
}

@Override
public Class getDriverInterface() {
    return DrupalDriver.class;
}

@Override
protected void connectSensors() {
    super.connectSensors();
    FunctionSensorAdapter serviceUpAdapter = sensorRegistry.register(new ServiceUpSensorAdapter());
    serviceUpAdapter.poll(SERVICE_UP);
}

private class ServiceUpSensorAdapter extends FunctionSensorAdapter {

    public ServiceUpSensorAdapter() {
        //we want to scan every 10 seconds.
        super(MutableMap.of("period", new TimeDuration(0, 0, 10, 0)));
    }

    @Override
    public Object call() {
        return getDriver().isRunning();
    }
}
}

[ahgittin]

i'm not encountering this. i've removed all the eclipse + groovy references in the pom and it compiles fine for me. see:

https://github.com/ahgittin/brooklyn-social-apps/compare/fix;pom-tidy

what version of java are you running? i'm on 1.6.0_37. there is a fix somewhere between 1.6.0_16 and 1.6.0_23 which fixes some problems in this area, according to:

http://stackoverflow.com/questions/4829576/javac-error-inconvertible-types-with-generics

[pveentjer]

Hi Alex,

I'm running:

PVeentjer-3:base alarmnummer$ java -version java version "1.7.0_09" Java(TM) SE Runtime Environment (build 1.7.0_09-b05) Java HotSpot(TM) 64-Bit Server VM (build 23.5-b02, mixed mode)

[pveentjer]

When I switch to:

PVeentjer-3:brooklyn-social-apps alarmnummer$ java -version java version "1.6.0_29" Java(TM) SE Runtime Environment (build 1.6.0_29-b11-402-11M3909) Java HotSpot(TM) 64-Bit Server VM (build 20.4-b02-402, mixed mode) PVeentjer-3:brooklyn-social-apps alarmnummer$

The problem is not happening. So perhaps the bug is not solved in 1.7?

[pveentjer]

And switching back to 1.7 gives the initial compilation error.

[pveentjer]

I just had a quick peek at the places that actually implement and parametrize Rebindable. For entities, it only happens on Entity. There is no deep hierarchy of type parameter passing. So I really don't understand why the javac would complain about this extremely basic usage of generics.

[ahgittin]

I suspect the groovy compiler is doing something funny at AbstractEntity.

I wonder if inserting a new (java) interface RebindableEntity extends Rebindable in the hierarchy would help.

Best, Alex On Nov 29, 2012 11:40 AM, "Peter Veentjer" notifications@github.com wrote:

I just had a quick peek at the places that actually implement and parametrize Rebindable. For entities, it only happens on Entity. There is no deep hierarchy of type parameter passing. So I really don't understand why the javac would complain about this extremely basic usage of generics.

— Reply to this email directly or view it on GitHubhttps://github.com/brooklyncentral/brooklyn/issues/406#issuecomment-10862913.

[pveentjer]

Just tried it:

 public class Drupal extends SoftwareProcessEntity implements Rebindable<EntityMemento> {

That doesn't solve the problem.

I also tried to cheat my way out relying on a covariant return type instead of generics:

 public interface Entity extends Serializable, Rebindable{

      RebindSupport<EntityMemento> getRebindSupport();
 }

But that also didn't solve the problem..

I'm going to compile the API module without the groovy compiler in place and see what happens.

[pveentjer]

Also tried building the API module with javac and core/base with groovy. Also didn't solve the problem.

[pveentjer]

Now trying to make AbstractEntity also implement Rebindable...

[edit] problem remains... nasty little creature.

[pveentjer]

Problem is solved. I have tried the covariant return type again and this time it apparently didn't cause problems.

So Brooklyn can now be used in a project so that:

• this project doesn't rely on the groovy compiler
• can be used with java 7