Using JournalArticleService in startup action component

[Abhishek Suthar，修改在7 年前。]

Hello Developers,

I have created simple startup action component using OSGI DS annotation. I want to access journal articles when liferay starts.But some how I'm not able to access journal Article service.

Please find my code below,

package com.example.api;
 
import org.osgi.service.component.annotations.Component;
import org.osgi.service.component.annotations.Reference;
import org.osgi.service.component.annotations.ReferenceCardinality;
import org.osgi.service.component.annotations.ReferencePolicy;
import org.osgi.service.component.annotations.ReferencePolicyOption;
 
import com.liferay.journal.service.JournalArticleLocalService;
import com.liferay.portal.kernel.events.ActionException;
import com.liferay.portal.kernel.events.LifecycleAction;
import com.liferay.portal.kernel.events.LifecycleEvent;
 
@Component(
       
        property={"key=application.startup.events"},
        service = LifecycleAction.class
        )
public class StartupActionapi implements LifecycleAction {
 
    @Override
    public void processLifecycleEvent(LifecycleEvent lifecycleEvent) throws ActionException {
        System.out.println("Im starting man>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>");
        System.out.println("journel>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>");
        System.out.println("+++++++++++++++++++++"+_journalArticleLocalService.getArticles().size());
    }
   
    @Reference(cardinality = ReferenceCardinality.OPTIONAL,
            policy = ReferencePolicy.DYNAMIC,
            policyOption = ReferencePolicyOption.GREEDY)
    protected void setJournalArticleLocalService(
        JournalArticleLocalService journalArticleLocalService) {
 
        _journalArticleLocalService = journalArticleLocalService;
    }
   
    protected void unsetJournalArticleLocalService(
            JournalArticleLocalService journalArticleLocalService) {
 
            _journalArticleLocalService = null;
        }
       
   
    private JournalArticleLocalService _journalArticleLocalService;
   
}

Getting first two system outs in logs BUT,
I'm getting nullpointer on below line,

 System.out.println("+++++++++++++++++++++"+_journalArticleLocalService.getArticles().size());

[Eduardo P. García，修改在3 年前。]

Hi Abhishek,

If you want to make sure the JournalService is available when your module starts, then you shouldn't declare your dependency with the journalService as "OPTIONAL".

Regards

[Abhishek Suthar，修改在7 年前。]

Eduardo P. Garcia:

Hi Abhishek,

If you want to make sure the JournalService is available when your module starts, then you shouldn't declare your dependency with the journalService as "OPTIONAL".

Regards

When I change it to MANDATORY. I'm not getting first two sysouts in logs. I think bundle not even starts.

When I change to "OPTIONAL" it shows the first two sysouts and then null pointer.