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LinkFieldDefinition renders a text field and a browse button that allows the user to select an item from a configured app. The link field is used to select targets inside Magnolia, for example a page to tease, an asset to render an image, etc.. The link field stores a reference to the selected item.

The link field allows you to choose items from any content app, including non-JCR apps. 

Class: info.magnolia.ui.form.field.definition.LinkFieldDefinition

The central property when defining a link field is appName - the name of the Magnolia app to choose the item from. The target app is responsible for providing a view that is suitable for selecting the item. When the target app is a content app, the workbench in the browser subapp is a suitable view and it is used by default. For more complex apps like the Assets app,  a choose dialog is configured in the app to browse the contents. 

Link field properties

Simple link field definition

form:
 tabs:
    - name: tabImage
      label: Image 
      fields:
        - name: image
          class: info.magnolia.ui.form.field.definition.LinkFieldDefinition
          targetWorkspace: dam
          appName: assets
          label: Select image
          identifierToPathConverter:
            class: info.magnolia.dam.app.assets.field.translator.AssetCompositeIdKeyTranslator
          contentPreviewDefinition:
            contentPreviewClass: info.magnolia.dam.app.ui.field.DamFilePreviewComponent
Node nameValue

 form


 tabs


 tabImage


 fields


 image


 identifierToPathConverter


 class

info.magnolia.dam.app.assets.field.translator.AssetCompositeIdKeyTranslator

 contentPreviewDefinition


 contentPreviewClass

info.magnolia.dam.app.ui.field.DamFilePreviewComponent

 appName

contacts

 class

info.magnolia.ui.form.field.definition.LinkFieldDefinition

 targetWorkspace

dam

 label

Select image

 label

Image


You can use common field properties and the following properties in a link field definition:

Properties:

<field name>Name of field.

appName

required

Target app name used to create the content view to choose the item from.

All content apps provide a workbench. The workbench view is used as the link target chooser by default. However, you can also provide a choose dialog and provide custom actions. See an example in /modules/dam/apps/assets/chooseDialog .

targetWorkspace

optional, default is website

Name of the workspace in which the target content is stored if the content app is JCR based. Examples:

appNametargetWorkspace
pageswebsite
assetsdam
contactscontacts
categoriescategory

fieldEditable

optional, default is true

Makes the text box displaying the link editable once a target has been selected.

buttonSelectNewLabel

optional, default is Select new...

Button label before the target node is selected. The value is i18n-able.

buttonSelectOtherLabel

optional, default is Select another...

Button label after the target node is selected. The value is i18n-able.

targetTreeRootPath

optional, default is /

Path in the workspace that browsing is limited to. The user can start browsing at this path but they cannot navigate to nodes above or at the same level as the target path. Use this property to restrict selecting of items to a particular folder.

identifierToPathConverter

optional

The link field returns the path of the selected node by default. You can convert the path to a UUID with a converter. 

class

optional

Any class that implements the IdentifierToPathConverter interface. Examples:

  • info.magnolia.ui.form.field.converter.BaseIdentifierToPathConverter

  • info.magnolia.dam.app.assets.field.translator.AssetCompositeIdKeyTranslator converts an asset composite ID key to a path.

contentPreviewDefinition

optional

Render a preview of the selected content. The preview component typically displays an image thumbnail and some metadata.  

contentPreviewClass

optional

Any class that implements the ContentPreviewComponent interface. Examples:

  • info.magnolia.contacts.app.field.component.ContactPreviewComponent displays a contact thumbnail and information.

  • info.magnolia.dam.app.ui.field.DamFilePreviewComponent. Displays an asset thumbnail and related information.

The link field also allows you to choose items from non-JCR apps.

To understand the process when choosing an item from a content app via link field, basic knowledge of the Content app framework and the nature of LinkField is necessary.

Things to note about LinkField:

  • It extends a custom Vaadin field,
  • It stores a value which must be String.
  • It has a callback ( ChooseDialogCallback ). 
  • When choosing an item, the method #onItemChosen(actionName, chosenValue) is triggered on the callback. The parameter choosenValue is of type Object and is the corresponding ItemId of the item of the content app. (See ItemIds and Items). 

Depending on the implementation of the content app, the ItemId may be a String or a more complex Object. A well-known ItemId is JcrItemId . The callback properly handles JcrItemId, and if it is another type, String.valueOf(chosenValue) is saved to the link field.

 Click to expand to see LinkFieldFactory#createChooseDialogCallback (158 - 189)
    protected ChooseDialogCallback createChooseDialogCallback() {
        return new ChooseDialogCallback() {
 
            @Override
            public void onItemChosen(String actionName, final Object chosenValue) {
                String newValue = null;
                if (chosenValue instanceof JcrItemId) {
                    String propertyName = definition.getTargetPropertyToPopulate();
                    try {
                        javax.jcr.Item jcrItem = JcrItemUtil.getJcrItem((JcrItemId) chosenValue);
                        if (jcrItem.isNode()) {
                            final Node selected = (Node) jcrItem;
                            boolean isPropertyExisting = StringUtils.isNotBlank(propertyName) && selected.hasProperty(propertyName);
                            newValue = isPropertyExisting ? selected.getProperty(propertyName).getString() : selected.getPath();
                        }
                    } catch (RepositoryException e) {
                        log.error("Not able to access the configured property. Value will not be set.", e);
                    }
                } else {
                    newValue = String.valueOf(chosenValue);
                }
                linkField.setValue(newValue);
                linkField.getSelectButton().setEnabled(true);
            }
 
            @Override
            public void onCancel() {
                linkField.getSelectButton().setEnabled(true);
            }
        };
    }
}

When using LinkField with  JCR-agnostic target apps that use complex ItemIds that extend  Object , override the public String toString() method on the implementation of the itemId.

If LinkField does not work for your custom content app, create a custom link field. See Custom fields for more.

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