Issue in Sling Model instantiating from Sightly | Community
Skip to main content
A
AnujaRa
New Participant
September 17, 2025
Solved

Issue in Sling Model instantiating from Sightly

  • September 17, 2025
  • 2 replies
  • 1069 views

Hi 

I’m trying to use a simple Sling Model from HTL, but the model never instantiates (null bindings). I suspect I’m missing something obvious with the adaptable.

Sling Model

package com.acme.core.models;

import javax.inject.Inject;
import org.apache.sling.api.resource.Resource;
import org.apache.sling.models.annotations.DefaultInjectionStrategy;
import org.apache.sling.models.annotations.Model;

@Model(
adaptables = Resource.class,
defaultInjectionStrategy = DefaultInjectionStrategy.OPTIONAL
)
public class TeaserModel {

@586265
private String title;

public String getTitle() {
return title;
}
}

 

Sightly

<div data-sly-use.m="com.acme.core.models.TeaserModel">
<h2>${m.title}</h2>
</div>

 

When I check the logs here is what I get, what wrong here?

org.apache.sling.models.impl.ModelAdapterFactory Could not adapt
org.apache.sling.api.SlingHttpServletRequest to com.acme.core.models.TeaserModel

Best answer by SantoshSai

Hi @anujara,

I think, HTL tries to adapt from the request by default, but your model is Resource-adaptable.

You have 2 options:

1. Make the model request-adaptable (HTL unchanged):

@Model(
  adaptables = org.apache.sling.api.SlingHttpServletRequest.class,
  defaultInjectionStrategy = DefaultInjectionStrategy.OPTIONAL
)
public class TeaserModel {
  @org.apache.sling.models.annotations.injectorspecific.ValueMapValue(
    name = org.apache.jackrabbit.JcrConstants.JCR_TITLE
  )
  private String title;
  public String getTitle() { return title; }
}

2. Keep Resource-adaptable and force resource adaptation in HTL:

<div data-sly-use.m="${'com.acme.core.models.TeaserModel' @ resource=resource}">
  <h2>${m.title}</h2>
</div>

Also, I see property name mismatch in your code: Field is title, but the JCR property is jcr:title. With plain @Inject it won’t map.
Try to use @ValueMapValue(name = "jcr:title") (shown above) or rename the field to jcr:title (not recommended).

2 replies

SantoshSai
SantoshSaiAccepted solution
New Participant
September 17, 2025

Hi @anujara,

I think, HTL tries to adapt from the request by default, but your model is Resource-adaptable.

You have 2 options:

1. Make the model request-adaptable (HTL unchanged):

@Model(
  adaptables = org.apache.sling.api.SlingHttpServletRequest.class,
  defaultInjectionStrategy = DefaultInjectionStrategy.OPTIONAL
)
public class TeaserModel {
  @org.apache.sling.models.annotations.injectorspecific.ValueMapValue(
    name = org.apache.jackrabbit.JcrConstants.JCR_TITLE
  )
  private String title;
  public String getTitle() { return title; }
}

2. Keep Resource-adaptable and force resource adaptation in HTL:

<div data-sly-use.m="${'com.acme.core.models.TeaserModel' @ resource=resource}">
  <h2>${m.title}</h2>
</div>

Also, I see property name mismatch in your code: Field is title, but the JCR property is jcr:title. With plain @Inject it won’t map.
Try to use @ValueMapValue(name = "jcr:title") (shown above) or rename the field to jcr:title (not recommended).

Santosh Sai
    A
    AnujaRaAuthor
    New Participant
    September 17, 2025

    @santoshsai Thanks for the last point you mentioned about mapping title field, inititally I tried SlingHttpServletRequest but may be because of field mismatch it didn't worked but now it worked!

    giuseppebaglio
    giuseppebaglio
    New Participant
    September 17, 2025

    Your model says it adapts from Resource.class, but HTL uses the SlingHttpServletRequest as the adaptable by default when using data-sly-use. Because the model isn’t configured to adapt from request, adaptation fails and returns null. 

    Change your model to adapt from SlingHttpServletRequest.class

    @Model(adaptables = SlingHttpServletRequest.class, defaultInjectionStrategy = DefaultInjectionStrategy.OPTIONAL) public class TeaserModel { @586265 private String title; public String getTitle() { return title; } }

    This way, when HTL runs data-sly-use, it adapts the current request to your model, which matches the adaptable.

     
     
      Terms & ConditionsAccessibility statement

      Loading footer...