org.apache.cocoon.transformation
Class VariableRewriterTransformer

java.lang.Object
  extended byorg.apache.cocoon.util.AbstractLogEnabled
      extended byorg.apache.cocoon.xml.AbstractXMLProducer
          extended byorg.apache.cocoon.xml.AbstractXMLPipe
              extended byorg.apache.cocoon.transformation.AbstractTransformer
                  extended byorg.apache.cocoon.transformation.AbstractSAXTransformer
                      extended byorg.apache.cocoon.transformation.VariableRewriterTransformer
All Implemented Interfaces:
Configurable, ContentHandler, Disposable, Initializable, LexicalHandler, Poolable, Recyclable, Serviceable, org.apache.cocoon.sitemap.SitemapModelComponent, org.apache.cocoon.transformation.Transformer, org.apache.cocoon.xml.XMLConsumer, XMLConsumer, org.apache.cocoon.xml.XMLPipe, org.apache.cocoon.xml.XMLProducer

public class VariableRewriterTransformer
extends org.apache.cocoon.transformation.AbstractSAXTransformer
implements Initializable, Disposable

Rewrites URIs in links to a value determined by an InputModule. The URI scheme identifies the InputModule to use, and the rest of the URI is used as the attribute name.

Example

For instance, if we had an XMLFileModule, configured to read values from an XML file:
 <site>
   <faq>
     <how_to_boil_eggs href="faq/eggs.html"/>
   </faq>
 </site>
 
mapped to the prefix 'site:', then <link href="site:/site/faq/how_to_boil_eggs/@href"> would be replaced with <link href="faq/eggs.html">

InputModules are configured twice; first statically in cocoon.xconf, and then dynamically at runtime, with dynamic configuration (if any) taking precedence. VariableRewriterTransformer allows you to pass a dynamic configuration to used InputModules as follows.

First, a template Configuration is specified in the static <map:components> block of the sitemap:

  <map:transformer name="linkrewriter"
    src="org.apache.cocoon.transformation.VariableRewriterTransformer">
    <input-module name="site" src="cocoon://samples/link/linkmap" reloadable="true"/>
    <input-module name="mapper">
      <input-module name="site" src="{src}" reloadable="true"/>
      <prefix>/site/</prefix>
      <suffix>/@href</suffix>
    </input-module>
  </map:transformer>
 
Here, we have established dynamic configuration templates for two modules, 'site' (an XMLFileModule and 'mapper' (A SimpleMappingMetaModule. All other InputModules will use their static configs. Note that the dynamic config syntax different to the static config syntax (attributes instead of elements). Note also that, when configuring a Meta InputModule like 'mapper', we need to also configure the 'inner' module (here, 'site') with a nested <input-module>.

There is one further twist; to have really dynamic configuration, we need information available only when the transformer actually runs. This is why the above config was called a "template" Configuration; it needs to be 'instantiated' and provided extra info, namely:

With the above config template, we can have a matcher like:
    <map:match pattern="**welcome">
      <map:generate src="index.xml"/>
      <map:transform type="linkrewriter" src="cocoon:/{1}linkmap"/>
      <map:serialize type="xml"/>
    </map:match>
 
Which would cause the 'mapper' XMLFileModule to be configured with a different XML file, depending on the request.

Similarly, we could use a dynamic prefix:

      <prefix>{prefix}</prefix>
 
in the template config, and:
   <map:parameter name="prefix" value="/site/"/>
 
in the map:transform

Configuration

The following map:parameter's are recognised:

link-attrs
Space-separated list of attributes to consider links (to be transformed). Defaults to 'href'.
schemes
Space-separated list of URI schemes to explicitly include. If specified, all URIs with unlisted schemes will not be converted.
exclude-schemes
Space-separated list of URI schemes to explicitly exclude.
bad-link-str
String to use for links with a correct InputModule prefix, but no value therein. Defaults to the original URI.

Note that currently, only links in the default ("") namespace are converted.

Version:
$Id: VariableRewriterTransformer.html 1304280 2012-03-23 11:18:01Z ilgrosso $

Field Summary
 
Fields inherited from class org.apache.cocoon.transformation.AbstractSAXTransformer
context, defaultNamespaceURI, EMPTY_ATTRIBUTES, ignoreEmptyCharacters, ignoreEventsCount, ignoreHooksCount, ignoreWhitespaces, manager, namespaceURI, objectModel, parameters, recorderStack, removeOurNamespacePrefixes, request, resolver, response, source, stack
 
Fields inherited from class org.apache.cocoon.xml.AbstractXMLProducer
contentHandler, EMPTY_CONTENT_HANDLER, lexicalHandler, xmlConsumer
 
Fields inherited from interface org.apache.cocoon.transformation.Transformer
ROLE
 
Constructor Summary
VariableRewriterTransformer()
          Constructor.
 
Method Summary
 void characters(char[] p0, int p1, int p2)
          Process the SAX event.
 void configure(Configuration conf)
          Configure this component from the map:transformer block.
 void dispose()
           
 void initialize()
          Initiate resources prior to this component becoming active.
 void recycle()
          Recycle this component for use in another map:transform.
 void setup(org.apache.cocoon.environment.SourceResolver resolver, Map objectModel, String src, Parameters parameters)
          Setup this component to handle a map:transform instance.
 void startTransformingElement(String uri, String name, String raw, Attributes attr)
          Start processing elements of our namespace.
 
Methods inherited from class org.apache.cocoon.transformation.AbstractSAXTransformer
addRecorder, comment, endCDATA, endDocument, endDTD, endElement, endEntity, endParametersRecording, endParametersRecording, endPrefixMapping, endRecording, endSAXRecording, endSerializedXMLRecording, endTextRecording, endTransformingElement, findPrefixMapping, getMutableAttributes, ignorableWhitespace, processingInstruction, removeRecorder, sendEndElementEvent, sendEndElementEventNS, sendEndPrefixMapping, sendEvents, sendParametersEvents, sendStartElementEvent, sendStartElementEvent, sendStartElementEventNS, sendStartElementEventNS, sendStartPrefixMapping, sendTextEvent, service, setDocumentLocator, setupTransforming, skippedEntity, startCDATA, startDocument, startDTD, startElement, startEntity, startParametersRecording, startPrefixMapping, startRecording, startSAXRecording, startSerializedXMLRecording, startTextRecording
 
Methods inherited from class org.apache.cocoon.xml.AbstractXMLProducer
setConsumer, setContentHandler, setLexicalHandler
 
Methods inherited from class org.apache.cocoon.util.AbstractLogEnabled
getLogger, setLogger
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 
Methods inherited from interface org.apache.cocoon.xml.XMLProducer
setConsumer
 

Constructor Detail

VariableRewriterTransformer

public VariableRewriterTransformer()
Constructor. Set the namespace.

Method Detail

configure

public void configure(Configuration conf)
               throws ConfigurationException
Configure this component from the map:transformer block. Called before initialization and setup.

Specified by:
configure in interface Configurable
Throws:
ConfigurationException

initialize

public void initialize()
                throws Exception
Initiate resources prior to this component becoming active.

Specified by:
initialize in interface Initializable
Throws:
Exception

setup

public void setup(org.apache.cocoon.environment.SourceResolver resolver,
                  Map objectModel,
                  String src,
                  Parameters parameters)
           throws org.apache.cocoon.ProcessingException,
                  SAXException,
                  IOException
Setup this component to handle a map:transform instance.

Specified by:
setup in interface org.apache.cocoon.sitemap.SitemapModelComponent
Throws:
org.apache.cocoon.ProcessingException
SAXException
IOException

startTransformingElement

public void startTransformingElement(String uri,
                                     String name,
                                     String raw,
                                     Attributes attr)
                              throws org.apache.cocoon.ProcessingException,
                                     IOException,
                                     SAXException
Start processing elements of our namespace. This hook is invoked for each sax event with our namespace.

Parameters:
uri - The namespace of the element.
name - The local name of the element.
raw - The qualified name of the element.
attr - The attributes of the element.
Throws:
org.apache.cocoon.ProcessingException
IOException
SAXException

characters

public void characters(char[] p0,
                       int p1,
                       int p2)
                throws SAXException
Process the SAX event.

Specified by:
characters in interface ContentHandler
Throws:
SAXException

recycle

public void recycle()
Recycle this component for use in another map:transform.

Specified by:
recycle in interface Recyclable

dispose

public void dispose()
Specified by:
dispose in interface Disposable


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