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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

fieldType: link

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
          fieldType: link
          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

 fieldType

link

 targetWorkspace

dam

 label

Select image

 label

Image


See Referencing fields for further information.

Field-specific 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 .

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.

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.

fieldEditable

optional, default is true

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

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.

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.

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

Common field properties :

fieldType

or

class

required

Defines the field type via either a field alias name or a fully-qualified field definition class name. See Field definition: Field types.

To check the correct form of the name, use the Definitions app.

defaultValue

optional

Pre-filled default value displayed in the field. The value can be overwritten by the user. Use alphanumeric characters.

(info) Applied only when creating a new item, not for already existing items.

description

optional

Help text displayed when the user clicks the help icon. The value can be literal or retrieved from the message bundle with a key. Use alphanumeric characters in literal values. Not applicable to the static field.

i18n

optional, default is false

Enables i18n authoring support which allows editors to write foreign-language or regionally targeted content. A two-letter language identifier (en, de, fr etc.) is displayed on controls where i18n is set to true.

i18nBasename

optional, default is the message bundle defined in the dialog definition

Message bundle such as com.example.messages for localized field labels. You can set this property in the parent dialog, form or tab definition. Child fields will inherit the bundle.

label

optional

Field label displayed to editors. The value can be literal such as Product name or retrieved from the message bundle with a key such as products.product.label. Use alphanumeric characters in literal values.

If you don't provide the property then Magnolia falls back to a generated i18n key and displays they key in the UI.

If you don't want a label at all then define the property and set its value to empty space such as label: " " in YAML.

name

optional, default is the name of the field's parent node

Name of the node where the value is saved. The name jcrName is reserved. Use alphanumeric characters.

placeholder

optional

The placeholder text to be displayed in the empty field. The property replaces the deprecated placeholder text field.

(warning) Applicable in the textlink and comboBox fields.

The field is optional, but you should provide a translation or a hard-coded label, otherwise the empty field will display its auto-generated 18n key instead.

readOnly

optional, default is false

Makes the field uneditable. Adding this property has the same effect as creating a static field.

required

optional, default is false

Makes the field required (mandatory). An asterisk is displayed next to the field label. See also Checking for null values.

requiredErrorMessage

optional, default is "This field is required"

Error message displayed when required is true and the user saves an empty field. The value can be literal or retrieved from the message bundle with a key such as validation.message.required.

styleName

optional

Adds one or more style names to this component. Multiple styles can be specified as a space-separated list of style names such as checkbox disabled. The style name will be rendered as an HTML class name, which can be used in a CSS definition. The class name is added to the field by calling the Vaadin method addStyleName.

transformerClass

optional

Property transformer classes define how field values are stored in the repository. Each field has a default transformer class. You don't need to define a class unless you want to override the default. The value is a fully-qualified class name.

(warning) Complex field definitions may define a different default transformer in their constructor. See Transforming field values for more.

type

optional, most fields set a default value automatically

JCR property type of the stored value such as String, Boolean, Date or any other supported and defined data type. 

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.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.