/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.cocoon.portal.transformation;
import org.apache.cocoon.portal.coplet.CopletInstanceData;
import org.apache.cocoon.portal.event.impl.CopletLinkEvent;
import org.apache.cocoon.xml.AttributesImpl;
import org.apache.cocoon.xml.XMLUtils;
import org.xml.sax.Attributes;
import org.xml.sax.ContentHandler;
import org.xml.sax.SAXException;
/**
* This transformer is used to replace links (URIs) from elements
* like <a href="URI"> or <form action="URI"> with portal
* event uris. Therefore the transformer searches for <eventlink>
* elements replaces the URI form the attribute which is specified within
* an attribute called "attribute" and renames the element as specified
* within an attribute called "element".
*
* Example:<br><br>
*
* <pre>
* <root xmlns:ev="http://apache.org/cocoon/portal/eventlink/1.0">
* <ev:eventlink href="http://eventlinkexample" element="a" attribute="href">linktext</ev:eventlink>
* </root><br></pre>
*
* will be replaced with something like:<br><br>
*
* <pre>
* <root>
* <a href="portal?cocoon-portal-event=8">linktext</a>
* </root><br></pre>
*
* The transformer will create two CopletLinkEvents and insert corresponding links
* to them to the XML instead of "http://eventlinkexample". If such a link is pressed
* the corresponding CopletLinkEvent is sent to the Subscribers to be handled.<br>
* Please see also the documentation of superclass AbstractCopletTransformer for how
* the coplet instance data are acquired.
*
* @author <a href="mailto:gernot.koller@rizit.at">Gernot Koller</a>
*
* @version CVS $Id$
*/
public class NewEventLinkTransformer extends AbstractCopletTransformer {
/**
* The namespace URI to listen for.
*/
public static final String NAMESPACE_URI =
"http://apache.org/cocoon/portal/eventlink/1.0";
/**
* The XML element name to listen for.
*/
public static final String EVENT_ELEM = "eventlink";
/**
* An attribute's name of EVENT_ELEMENT.
*/
public static final String ATTRIBUTE_ATTR = "attribute";
/**
* An attribute's name of EVENT_ELEMENT.
*/
public static final String ELEMENT_ATTR = "element";
/**
* @see java.lang.Object#Object()
*/
public NewEventLinkTransformer() {
this.defaultNamespaceURI = NAMESPACE_URI;
}
/**
* @throws SAXException when the eventlink element does not contain the necessary attributes
* "element" and "attribute", retrieving the LinkURI from the LinkService fails,
* or an unknown element within the namespaces in encountered.
* @see org.apache.cocoon.transformation.AbstractSAXTransformer#startTransformingElement(String, String, String, Attributes)
*/
public void startTransformingElement(String uri,
String name,
String raw,
Attributes attributes)
throws SAXException {
if (!EVENT_ELEM.equals(name)) {
throw new SAXException("Unknown element encountered: " + name);
}
String attributeName = attributes.getValue(ATTRIBUTE_ATTR);
String elementName = attributes.getValue(ELEMENT_ATTR);
if (attributeName == null) {
throw new SAXException(
"Element "
+ EVENT_ELEM
+ " must have an attribute "
+ ATTRIBUTE_ATTR
+ ".");
}
if (elementName == null) {
throw new SAXException(
"Element "
+ EVENT_ELEM
+ " must have an attribute "
+ ELEMENT_ATTR
+ ".");
}
// remove ATTRIBUTE_ATTR, "coplet" and ELEMENT_ATTR from attributes
AttributesImpl newAttributes = this.getMutableAttributes(attributes);
newAttributes.removeAttribute(ELEMENT_ATTR);
newAttributes.removeAttribute(ATTRIBUTE_ATTR);
newAttributes.removeAttribute("coplet");
int index = newAttributes.getIndex(attributeName);
String link = newAttributes.getValue(index);
boolean formSpecialTreatment = false;
if ("form".equals(elementName)) {
//cut all query parameters from actions with method get, as these will be normaly ignored!
formSpecialTreatment = true;
if ("GET".equalsIgnoreCase(newAttributes.getValue("method"))
&& link.indexOf('?') > 0) {
link = link.substring(0, link.indexOf('?'));
}
}
String portalAction = null;
String portalEvent = null;
// if attribute found that contains a link
if (link != null) {
CopletInstanceData cid = this.getCopletInstanceData(attributes.getValue("coplet"));
// create event link
CopletLinkEvent event = new CopletLinkEvent(cid, link);
String eventLink = this.portalService.getComponentManager().getLinkService().getLinkURI(event);
//form elements need hidden inputs to change request parameters
if (formSpecialTreatment) {
int pos = eventLink.indexOf("cocoon-portal-action=");
if ( pos != -1 ) {
int begin = pos + "cocoon-portal-action=".length();
int end = eventLink.indexOf('&', begin);
if (end == -1) {
end = eventLink.length();
}
portalAction = eventLink.substring(begin, end);
}
pos = eventLink.indexOf("cocoon-portal-event=");
if ( pos != -1 ) {
int begin = pos + "cocoon-portal-event=".length();
int end = eventLink.indexOf('&', begin);
if (end == -1) {
end = eventLink.length();
}
portalEvent = eventLink.substring(begin, end);
}
pos = eventLink.indexOf('?');
if ( pos != -1 ) {
eventLink = eventLink.substring(0, pos);
}
}
// insert event link
newAttributes.setValue(index, eventLink);
}
this.stack.push(elementName);
this.contentHandler.startElement(
"",
elementName,
elementName,
newAttributes);
//generate hidden inputs to add request parameters to the form action
if (formSpecialTreatment) {
this.sendHiddenFields(this.contentHandler, portalAction, portalEvent);
}
}
/**
* With forms the uri in the action attribute cannot be enhanced with request parameters.
* Instead hidden input fields must be inserted into the SAX stream to add request parameters.
* This method sends two hidden inputs adding the "cocoon-portal-action" parameter and
* the "cocoon-portal-event" parameter.
* @param contentHandler the content handler recieving the SAX events
* @param portalAction value of the "cocoon-portal-action" parameter
* @param portalEvent value of the "cocoon-portal-event" parameter
* @throws SAXException if sending the SAX events failed
*/
private void sendHiddenFields(ContentHandler contentHandler,
String portalAction,
String portalEvent)
throws SAXException {
if ( portalAction != null ) {
final AttributesImpl attributes = new AttributesImpl();
attributes.addCDATAAttribute("type", "hidden");
attributes.addCDATAAttribute("name", "cocoon-portal-action");
attributes.addCDATAAttribute("value", portalAction);
XMLUtils.createElement(contentHandler, "input", attributes);
}
if ( portalEvent != null ) {
final AttributesImpl attributes = new AttributesImpl();
attributes.addCDATAAttribute("type", "hidden");
attributes.addCDATAAttribute("name", "cocoon-portal-event");
attributes.addCDATAAttribute("value", portalEvent);
XMLUtils.createElement(contentHandler, "input", attributes);
}
}
/**
* @see org.apache.cocoon.transformation.AbstractSAXTransformer#endTransformingElement(String, String, String)
*/
public void endTransformingElement(String uri, String name, String raw)
throws SAXException {
String elementName = (String) this.stack.pop();
this.contentHandler.endElement("", elementName, elementName);
}
}