XForms ~ XBL ~ Library

Home ▸ XBL

Introduction

The XForms engine finds XBL bindings in the following ways:

1. Inline bindings, that is bindings under the form's xh:head, are always processed.
2. Bindings by name are searched in the Orbeon Forms resources.
3. Other bindings (such as bindings by attribute) are searched based on the oxf.xforms.xbl.library property.

Inline bindings

TODO

Bindings by name

Orbeon Forms allows for automatic inclusion of XBL bindings when matching by name only. This avoids including the XBL for those components in all the forms that use them. In addition, the bindings can be shared among forms, which saves memory and makes loading them faster.

Automatic inclusion works by defining a mapping between:

• the XML namespace in which your XBL components are
• and a directory containing the XBL file

Then, following a naming convention (more on this below), your XBL is automatically loaded by the XForms engine.

Properties starting with oxf.xforms.xbl.mapping specify a mapping between directory name an a URI:

<property as="xs:string" name="oxf.xforms.xbl.mapping.acme">
    http://www.acme.com/xbl
</property>

Consider an example, with the property above set:

1. Say element <acme:button> is found by the XForms engine, in your own http://www.acme.com/xbl namespace.
2. Orbeon Forms looks for a property with a name that starts with oxf.xforms.xbl.mapping and with a value is equal to the namespace in question (here http://www.acme.com/xbl). In this case it finds the property oxf.xforms.xbl.mapping.acme.
3. The XForms engine extracts the part of the property name after oxf.xforms.xbl.mapping. In this case it is acme.
4. This is used to resolve a resource called oxf:/xbl/acme/button/button.xbl.
   • The first part of the path is always xbl.
   • This is followed by the directory name found in step 3, here acme.
   • This is followed by a directory with the same name as the local name of your component, containing an XBL file also with the same name as your component, here: button/button.xbl.
   • The resource, if found, is automatically included in the page for XBL processing.

By default, all the <fr:*> elements are handled this way, and a mapping is already defined for those components as follows:

<property as="xs:string"  name="oxf.xforms.xbl.mapping.orbeon">
    http://orbeon.org/oxf/xml/form-runner
</property>

For example:

• <fr:number> is loaded from /xbl/orbeon/number/number.xbl
• <fr:section> is loaded from /xbl/orbeon/section/section.xbl

etc.

Other bindings

TODO