Level 2

ResourceChangeListener onChange event not getting trigger

Forum|Forum|6 years ago
April 23, 2019
1 reply
8807 views

Hi All,

the following code for onChange used to work in AEM 6.2 but after we migrated to 6.3 , I see onChange is not getting fired, not sure what is going wrong.

@Component(immediate = true)

@Service
@Properties(value = { @Property(name = ResourceChangeListener.PATHS, value = { CommunityConstants.CONTENT_ROOT_PATH }),

@Property(name = ResourceChangeListener.CHANGES, value = { "ADDED", "CHANGED" }, propertyPrivate = true) })

public class xyz implements ResourceChangeListener {

@Reference
private ResourceResolverFactory resourceResolverFactory;

@Reference
private ContentModelService contentModelService;

@Override
public void onChange(@Nonnull List<ResourceChange> changes) {

//some logic here

}

Please help me to understand it further.

Many Thanks,

Kranthi

This post is no longer active and is closed to new replies. Need help? Start a new post to ask your question.

joerghoh

Adobe Employee

Some basic checks first:

* Please check that the bundle containing this service is active.

* Please check that the component "xyz" is active (check on the Components list in the OSGI webconsole).

Jörg

smacdonald2008

Level 10

Issue is how session is obtained. You need to use a system user and give correct permissions. This works....

Component(immediate=true,
service= EventListener.class)
  
public class SimpleResourceListener implements EventListener{
  
   
    Logger log = LoggerFactory.getLogger(this.getClass());
     private Session adminSession;
       
      
     @Reference
     org.apache.sling.jcr.api.SlingRepository repository;
       
     @Activate
     public void activate(ComponentContext context) throws Exception {
     log.info("activating ExampleObservation");
     try {
         adminSession = repository.loginService("datawrite",null);
         adminSession.getWorkspace().getObservationManager().addEventListener(
          this, //handler
          Event.PROPERTY_ADDED|Event.NODE_ADDED, //binary combination of event types
          "/apps/example", //path
          true, //is Deep?
          null, //uuids filter
          null, //nodetypes filter
          false);
       
           
     } catch (RepositoryException e){
      log.error("unable to register session",e);
      throw new Exception(e);
     }
    }
    @Deactivate
    public void deactivate(){
     if (adminSession != null){
      adminSession.logout();
     }
    }
       
    public void onEvent(EventIterator eventIterator) {
      try {
        while (eventIterator.hasNext()){
          log.info("something has been added : {}", eventIterator.nextEvent().getPath());
        }
       } catch(RepositoryException e){
       log.error("Error while treating events",e);
      }
     }
    }

K

kranthivulpeAuthor

Level 2

Hi smacdonald2008 , this is what we are doing. so you suggest us to write `@Activate to get the session & @Deactivate to destroy the session ?`

package com.xyz.help.conteenginecore.listener;

import java.util.List;

import java.util.Optional;

import com.adobe.cq.social.community.api.CommunityConstants;

import com.xyz.help.conteenginecore.Constants;

import com.xyz.help.conteenginecore.ContentModel;

import com.xyz.help.conteenginecore.ContentModelService;

import com.google.common.annotations.VisibleForTesting;

import javax.annotation.Nonnull;

import org.apache.felix.scr.annotations.Component;

import org.apache.felix.scr.annotations.Properties;

import org.apache.felix.scr.annotations.Property;

import org.apache.felix.scr.annotations.Reference;

import org.apache.felix.scr.annotations.Service;

import org.apache.sling.api.resource.LoginException;

import org.apache.sling.api.resource.ModifiableValueMap;

import org.apache.sling.api.resource.PersistenceException;

import org.apache.sling.api.resource.Resource;

import org.apache.sling.api.resource.ResourceResolver;

import org.apache.sling.api.resource.ResourceResolverFactory;

import org.apache.sling.api.resource.ValueMap;

import org.apache.sling.api.resource.observation.ResourceChange;

import org.apache.sling.api.resource.observation.ResourceChangeListener;

import org.slf4j.Logger;

import org.slf4j.LoggerFactory;

/**
* Listens changing of resources, and in case when was added "articelNo"
* property, adding generated "articleId" property to the same node.
*/
@Component(immediate = true)

@Service
@Properties(value = { @Property(name = ResourceChangeListener.PATHS, value = { CommunityConstants.CONTENT_ROOT_PATH }),

@Property(name = ResourceChangeListener.CHANGES, value = { "ADDED", "CHANGED" }, propertyPrivate = true) })

public class GenerateArticleIdOnAddingArticleNumber implements ResourceChangeListener {

private static final Logger LOG = LoggerFactory.getLogger(GenerateArticleIdOnAddingArticleNumber.class);

@Reference
private ResourceResolverFactory resourceResolverFactory;

@Reference
private ContentModelService contentModelService;

@Override
public void onChange(@Nonnull List<ResourceChange> changes) {

try (ResourceResolver resolver = resourceResolverFactory
.getServiceResourceResolver(Constants.CONTENT_ENGINE_AUTH_INFO)) {

changes.stream().filter(resourceChange -> resourceChange.getAddedPropertyNames() != null)

.filter(resourceChange -> !resourceChange.getAddedPropertyNames().isEmpty())

.filter(resourceChange -> resourceChange.getAddedPropertyNames()

.contains(ContentModel.HelpArticle.PN_ARTICLE_NUMBER))

.forEach(resourceChange -> {

addArticleIdProperty(resourceChange, resolver);

addDefClassificationProperty(resourceChange, resolver);

});

resolver.commit();

} catch (LoginException e) {

LOG.error("Can't perform action", e);

} catch (PersistenceException e) {

LOG.error("Can't perform action", e);

}

private void addArticleIdProperty(ResourceChange resourceChange, ResourceResolver resourceResolver) {

Resource resource = resourceResolver.resolve(resourceChange.getPath());

Optional.ofNullable(resource.adaptTo(ModifiableValueMap.class)).ifPresent(valueMap -> valueMap

.put(ContentModel.HelpArticle.PN_ARTICLE_ID, contentModelService.generateArticleId(resource)));

}

private void addDefClassificationProperty(ResourceChange resourceChange, ResourceResolver resourceResolver) {

Resource resource = resourceResolver.resolve(resourceChange.getPath());

Optional.ofNullable(resource.adaptTo(ModifiableValueMap.class)).ifPresent(

valueMap -> valueMap.put(ContentModel.HelpArticle.PN_CLASSIFICATION, "ArticleClassification:help"));

}

@VisibleForTesting
void bindResourceResolverFactory(ResourceResolverFactory resolverFactory) {

this.resourceResolverFactory = resolverFactory;

}

@VisibleForTesting
void bindContentModelService(ContentModelService contentModelService) {

this.contentModelService = contentModelService;

}

when I install the bundle, I see null pointer exception

24.04.2019 09:49:34.993 *INFO* [Background Update com.xyz.help.content-engine-core-bundle (833)] com.xyz.help.conteenginecore.listener.GenerateArticleIdOnAddingArticleNumber activating ExampleObservation

24.04.2019 09:49:35.162 *ERROR* [FelixDispatchQueue] org.apache.sling.resourceresolver FrameworkEvent ERROR (java.lang.NullPointerException)

Hi smacdonald2008​ , this is what we are doing. so you suggest us to write @Activate to get the session & @Deactivate to destroy the session ?

Sign up

Login with SSO

Login to the community

Login with SSO

Scanning file for viruses.

This file cannot be downloaded

Hi smacdonald2008 , this is what we are doing. so you suggest us to write `@Activate to get the session & @Deactivate to destroy the session ?`