ResourceExistsSelector in Cocoon
ResourceExistsSelector
|
NAME |
resource-exists |
|
WHAT |
The ResourceExistsSelector component is used to select appropriate sitemap processing depending on the existence of a set of resources. |
|
TYPE |
Selector, Sitemap Component |
|
BLOCK |
Core |
|
CLASS |
org.apache.cocoon.selection.ResourceExistsSelector |
|
SINCE |
Cocoon 2.1 |
|
CACHEABLE |
not applicable |
Description
The ResourceExistsSelector selects the first of a set of Resources (usually files) that exists in the context.
Usage
Pipelines can be built based on the existence of files, for example building a PDF from XSL-FO or a higher-level XML format.
Sitemap pipeline examples
<map:match pattern="**.html">
<map:select type="resource-exists">
<map:when test="content/{1}.xml">
<map:generate src="content/{1}.xml" />
<map:transform src="stylesheets/page2html.xsl" />
</map:when>
<map:otherwise>
<map:generate src="resources/html/{1}.html" />
</map:otherwise>
</map:select>
<map:serialize type="html"/>
</map:match>
Sitemap component configuration example
<map:selectors...
<map:selector name="resource-exists"
src="org.apache.cocoon.selection.ResourceExistsSelector"
logger="sitemap.selector.resource-exists"
>
<map:parameter src="prefix" value="/"/>
</map:selector>
...
</map:selectors>
...
Configuration
The optional prefix parameter is prepended to all test expressions before evaluation. The default prefix is '/', meaning that all expressions are relative to the context root, unless explicitly overridden.
Setup
Setting up a ResourceExistsSelector includes choosing the <map:when> test expressions, and an optional <map:otherwise> clause.
History
03-19-03: initial creation
See also
A general documentation about selectors is available at Matchers and Selectors.
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