Developing Core Components

When to Use the Core Components?

As the Core Components are all-new, and offer multiple benefits, it is recommended for new AEM projects to use them. For existing projects, a migration should be part of a larger project effort, for example a rebranding or overall refactoring.

Therefore, Adobe provides following recommendations:

• New Projects
  New projects should always attempt to use Core Components. If Core Components cannot be used directly or extended to satisfy project requirements, then create a custom component following the component architecture set forth in core components. Except where not otherwise possible, avoid using the foundation components.
• Existing Projects
  Recommendation is keep using the foundation components, unless a site or component refactoring is planned.
  As they are very widely used by most existing projects, the foundation components will continue to be supported.
• New Custom Components
  Assess if an existing Core Component may be customized.
  If not, recommendation is to build a new custom component following the Component Guidelines.
• Existing Custom Components
  If your components work as expected, then keep them as they are.
  If not, refer to “New Custom Components” above.

How to Succeed with the Core Components

The Core Components are powerful, flexible, and easy to use and customize. Following a few key guidelines will ensure that your project with the Core Components is a success.

Migrating to the Core Components

Any new project should be implemented with Core Components. However existing projects will usually have extensive implementations of the Foundation Components.

Migrating from Foundation Components

A larger effort on an existing project (for example a rebranding or overall refactoring) often offers a chance to migrate to the Core Components. To facilitate this migration, Adobe has provided a number of migration tools to encourage the adoption of the Core Components and the latest AEM technology.

The AEM Modernization Tools allow for the easy conversion of:

• Static templates to editable templates
• Design configurations to policies
• Foundation Components to Core Components
• Classic UI to Touch-Enabled UI

For further information about the usage of these tools, see their documentation.

Migration via Move to AEM as a Cloud Service

Because AEM as a Cloud Service comes with the latest version of the Core Components automatically, when you move from an on-premises AEM installation, you will need to remove any dependency to the Core Components in your projects pom.xml file.

Your proxy components will still work as they did before because proxies point to the necessary supertype and the supertype path has the version in it. In this way, simply removing the dependency enables the Core Components to work in AEMaaCS just as they did on-premises.

Just like any other AEMaaCS project you will also need to add a dependency to the AEM SDK jar as well. This is not specific to the Core Components, but is required.

<dependency>
   <groupId>com.adobe.aem</groupId>
   <artifactId>aem-sdk-api</artifactId>
</dependency>

See the document AEM Project Structure for more information about AEMaaCS projects.

Core Component Support

Core Components are an integral part of AEM and supported as is, under the same terms and conditions as if they were delivered as part of the Quickstart.

Like other AEM product features, the general rule is: Components are first announced to be deprecated, and the earliest removed for the following AEM release. That gives customers at least one release cycle to move to the new version of the component, before dropping its support.

The version of each component clearly states the AEM versions that it supports. When support ceases for a version of AEM, then so does the support of the Core Components for that version of AEM.

For details about the support of component customizations, see the Customizing Core Components page.

Technical Capabilities

The following table gives an overview of the differences between core components and foundation components.

For details about their authoring capabilities and options to pre-configurable them, refer to the authoring page about them.

Component List

The following table lists the available Core Components, linking to their API, and indicates which foundation components they replace.

Upgrade of Core Components

One benefit of versioned components is that it allows to separate the migration to a new AEM version from the migration to new component versions. Also, if new component versions are available, it allows for the individual migration of each component to the new version.

Migrations to a new AEM version won’t impact how the Core Components work, provided that their versions also support the new AEM version that is being migrated to. Customizations made to the Core Components should not be affected either, as long as they don’t use APIs that have been deprecated or removed.

Migrations to new versions of the Core Components won’t impact how the component works either, but new features might be introduced to page authors, which might require some configuration by a template editor, in case the default behavior isn’t desired. Customizations however might need to be adapted, for more details see the Customizing Core Components page.

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