[[introduction]]
= Introduction

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In implementing the http://en.wikipedia.org/wiki/Naked_objects[naked objects pattern], Apache Causeway infers as much information from the domain classes as possible.
Nevertheless, some metadata relating solely to the UI is inevitably required.

The Apache Causeway programming model includes several mechanisms to influence the way in which the domain objects are rendered in the UI.

* the layout of application menu items (inferred from xref:domain-services.adoc[domain services])

* the layout of domain objects (xref:domain-entities.adoc[domain entities] and xref:view-models.adoc[view models]) allow the positioning of the xref:properties-collections-actions.adoc[object members] into columns and tabs

* UI hints provided by the domain object itself returning:

** the title so the end-user can distinguish one object from another
** an icon to indicate the type of object (and perhaps its state)
** CSS styles for additional adhoc styling
** an alternate layout, for example changed according to the roles of the end-user that is viewing it.

* in collections, how to customise which properties of the associated object appear as columns.

This page discusses these topics.
