Schemas and Documents

In Nuxeo EP 5, a fundamental entity is the document. A file, a note, a vacation request, an expense report, but also a folder, a forum, can all be thought of as documents. Objects that contain documents, like a folder or a workspace, are also themselves documents.

Any given document has a document type. The document type is specified at creation time, and does not change during the lifetime of the document. When referring to the document type, a short string is often used, for instance “Note” or “Folder”.

A document type is the grouping of several schemas. A schema represents the names and structure (types) of a set of fields in a document. For instance, a commonly-used schema is the Dublin Core schema, which specifies a standard set of fields used for document metadata like the title, description, modification date, etc.

To create a new document type, we start by creating one ore more schemas that the document type will use.

The schema is defined in a .xsd file (which obeys the standard XML Schema syntax) and is registered by a contribution to a schema extension point.

The document type is registered through a contribution to another doctype extension point, and will specify which schemas it uses. We also register the document type as a high-level type used by the EJB and rendering layers.

“Core” document types and “ECM” component types should not be confused. The former live in the core Nuxeo EP packages, the latter belong to the high level components. Apart from their definition, most of the uses of "document types" refer to the “ECM” kind.

<label>Sample document</label>
<icon>/icons/file.gif</icon>

The label and icon are used by the user interface, for instance in the creation page when a list of possible types is displayed. The icon is also used whenever a list of document wants to associate an icon with each.

<default-view>view_documents</default-view>

The default view specifies the name of the Facelet to use for this document if nothing is specified. This corresponds to a file that lives in the webapp, in this case view_documents.xhtml is a standard view defined in the base Nuxeo bundle, that takes care of displaying available tabs, and the document body according to the currently selected type. Changing it is not advised unless extremely nonstandard rendering is needed.

<type id="Folder" coretype="Folder">
  <subtypes>
    <type>Sample</type>
  </subtypes>
</type>
<type id="Workspace" coretype="Workspace">
  <subtypes>
    <type>Sample</type>
  </subtypes>
</type>

This contributes a rule to an already existing type, Folder. The subtypes element specifies which types can be created inside the type in which the element is embedded.

Here, we specify that our Sample type can be created in a Folder and a Workspace.

The goal is to contribute a way to define hidden cases for the subtypes definition. A syntax like the following can be used:

<type id="Workspace"> 
  <subtypes> 
    <type>Workspace</type> 
    <type hidden="create">Folder</type> 
    <type>File</type> 
    <type>Note</type> 
  </subtypes> 
</type>

If more than one hidden cases needs to be defined, then a syntax like the following can be used:

<type id="Workspace"> 
  <subtypes> 
    <type>Workspace</type> 
    <type hidden="create, paste">Folder</type> 
    <type>File</type> 
    <type>Note</type> 
  </subtypes> 
</type>

The hidden cases are stored in a list ([create, paste] for the above example), so if a check is needed for a hidden case, then the hidden cases list ought to be verified if contains that particular case.

The final OSGI-INF/ecm-types-contrib.xml looks like:

<?xml version="1.0"?>
<component name="org.nuxeo.project.sample.ecm.types">
  <extension target="org.nuxeo.ecm.platform.types.TypeService" point="types">
    <type id="Sample" coretype="Sample">
      <label>Sample document</label>
      <icon>/icons/file.gif</icon>
      <default-view>view_documents</default-view>
      <layout>
        <widget jsfcomponent="h:inputText"
          schemaname="dublincore" fieldname="title"
          required="true" />
        <widget jsfcomponent="h:inputTextarea"
          schemaname="dublincore" fieldname="description" />
        <widget jsfcomponent="h:inputText"
          schemaname="sample" fieldname="sample1" />
        <widget jsfcomponent="h:inputText"
          schemaname="sample" fieldname="sample2" />
      </layout>
    </type>
    <type id="Folder" coretype="Folder">
      <subtypes>
        <type>Sample</type>
      </subtypes>
    </type>
    <type id="Workspace" coretype="Workspace">
      <subtypes>
        <type>Sample</type>
      </subtypes>
    </type>
  </extension>
</component>