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anasustic
New Participant
June 29, 2022
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How to improve the code to get a child node ValueMap

  • June 29, 2022
  • 1 reply
  • 1168 views

I was getting a NullPointerException  in my method in the following line of code

 

ValueMap heroTeaserImageValueMap = resource.getChild("image").getValueMap()

so I rewrote it to:

ValueMap heroTeaserImageValueMap = getImageValueMap(heroTeaser);
private ValueMap getImageValueMap(Resource resource) {
    if (resource.hasChildren()) {
        return resource.getChild("image").getValueMap();
    } else {
        return ValueMap.EMPTY;
    }
}

This is not giving me the NullPointerException since I make sure I check if node has children nodes and from the data structure in the repo I know the child node name is image. Can someone suggest how I can improve this code. 

 

This is how the resource looks like in the repo

 "heroteaser": {
            "jcr:primaryType": "nt:unstructured",
            "targetBlank": "false",
            "bgColor": "blue",
            "teaserLead": "Home Hero Teaser Lead",
            "linkType": "button",
            "sling:resourceType": "xxx/heroTeaser",
            "teaserTitle": "Home Hero Teaser Title",
            "image": {
              "jcr:primaryType": "nt:unstructured",
              "fileReference": "/content/dam/xxx/Alltag_23-600x750.jpeg"
              }
            },
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Best answer by anasustic

@anasustic There is no need for this explicit check "resource.hasChildren()" as, when you say  "resource.getChild("image"), either it will return you the resource or a null.
So this is an extra overhead over here in the code.

Thanks


Thank you @shaileshbassi 

I simplified the code like this:

private ValueMap getImageValueMap(Resource resource) {

    Resource heroTeaserImageResource = resource.getChild("image");
    if (heroTeaserImageResource == null) {
        return ValueMap.EMPTY;
    }
    return heroTeaserImageResource.getValueMap();
}

1 reply

ShaileshBassi
ShaileshBassi
New Participant
June 29, 2022

@anasustic you can re-write the code in the below format:

Resource heroTeaserImageResource = resource.getChild("image");
if(null == heroTeaserImageResource ){
    return;
}
ValueMap heroTeaserImageValueMap = heroTeaserImageResource.getValueMap();
if( null == heroTeaserImageValueMap ) {
   return;
}

This way there will be no case that you end up in "NullPointerException" and if required you can add up the logger statements if required.

Thanks

    A
    anasusticAuthor
    New Participant
    June 29, 2022

    Hi @shaileshbassi 

    I rewrote it like this implementing your suggestion:

    private ValueMap getImageValueMap(Resource resource) {
        ValueMap heroTeaserImageValueMap = ValueMap.EMPTY;
        if (resource.hasChildren()) {
            Resource heroTeaserImageResource = resource.getChild("image");
            if (heroTeaserImageResource == null) {
                return heroTeaserImageValueMap;
            }
            heroTeaserImageValueMap = heroTeaserImageResource.getValueMap();
            if (heroTeaserImageValueMap == null) {
                return heroTeaserImageValueMap;
            }
        }
        return heroTeaserImageValueMap;
    }
      ShaileshBassi
      ShaileshBassi
      New Participant
      June 29, 2022

      @anasustic There is no need for this explicit check "resource.hasChildren()" as, when you say  "resource.getChild("image"), either it will return you the resource or a null.
      So this is an extra overhead over here in the code.

      Thanks

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