Content extensions
A content extension is either a contribution of content into a known anchor (similar to an
extension into an extension point), or the replacement of an existing element in a document.
Contributing into anchors
Anchor elements (e.g. <anchor id="my_anchor"/>) can be specified
in any user assistance XML document, and represent places at which other components are allowed
to extend this document. Specifying an anchor is as simple as adding the element in your markup.
To contribute content into an anchor, you must write the content to be added in a separate XML
file and hook it into the platform using one of two extension points. For help or
cheat sheet content, you must
use the
org.eclipse.help.contentExtension extension point. For
welcome(intro) extensions, use
org.eclipse.ui.intro.configExtension. The table of contents markup also allows the
special constructs
link and
link_to
which perform a similar function
to includes and contributions, but perform the additional operation of merging extra documents
to index for searching.
For example, let's say component A's documentation provides a listing of file formats it
supports. If component B extends A's support to several more formats, you can place an
anchor in A's list, and extend the list from B. For example:
<p>The following list shows the supported formats:</p>
<ul>
<li>Portable Network Graphics (.png)</li>
<li>Joint Photographic Experts Group (.jpeg)</li>
<li>Graphical Interchange Format (.gif)</li>
<!-- Extra formats go here -->
<anchor id="image_format_list"/>
</ul>
Then component B can make a contribution to the anchor to add more formats
to the list by specifying the following extension:
<extension point="org.eclipse.help.contentExtension">
<contentExtension
file="path/to/extension.xml"/>
</extension>
Where the file path/to/extension.xml might contain:
<contentExtension>
<contribution
content="docs/mydoc.xhtml#mycontent"
path="/component_a_plugin/docs/doc_with_anchor.xhtml#anchorId">
</contribution>
</contentExtension>
The element with the id attribute mycontent in document
docs/mydoc.xhtml would contain the content you wish to contribute
into the anchor. The result will be that when the user views the document, the extra content
will appear at the anchor as though it was explicitly added into the original document.
Replacing content
Any XML element in a user assistance document that has an id attribute that is
unique to that document can be replaced with any other element.
As with contributions into anchors, to replace an element, you must write the new element to
replace with in a separate XML file and hook it into the platform using one of two extension
points. For
help or
cheat sheet content,
you must use the
org.eclipse.help.contentExtension extension point. For
welcome (intro) extensions, use
org.eclipse.ui.intro.configExtension.
The only difference with replacements as opposed to contributions into anchors is the name of the
XML element used in the markup; use the replacement element instead of
contribution (or replacementContent in the case of welcome). For example:
<contentExtension>
<replacement
content="docs/mydoc.xml#myelement"
path="/plugin.id/path/doc.xml#elementId">
</replacement>
</contentExtension>
(Note the markup is different for welcome, as specified in the
org.eclipse.ui.intro.configExtension
extension point)
Path format
The format of the path attribute is /pluginId/path/file.xml#elementId,
except welcome where it is pageId/path/to/elementId where the pageId is the welcome
page id, and all other path segments are ids of container elements like groups, leading to the
target element.
