/*
* Copyright 1999-2004 The Apache Software Foundation.
*
* Licensed 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.generation;
import org.apache.avalon.framework.parameters.Parameters;
import org.apache.cocoon.ProcessingException;
import org.apache.cocoon.environment.ObjectModelHelper;
import org.apache.cocoon.environment.Request;
import org.apache.cocoon.environment.Session;
import org.apache.cocoon.environment.SourceResolver;
import org.apache.cocoon.xml.XMLUtils;
import org.apache.cocoon.xml.IncludeXMLConsumer;
import org.apache.excalibur.xml.sax.XMLizable;
import org.w3c.dom.Node;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.AttributesImpl;
import java.io.IOException;
import java.util.Map;
/**
* Generates a document from a session attribute. The attribute may be a DOM
* node, an <code>XMLizable</code>, or any other object, and is streamed using
* the same rules as for <xsp:expr> in XSPs (see {@link
* org.apache.cocoon.components.language.markup.xsp.XSPObjectHelper}).
* <p>
* Name of the session attribute is specified using src attribute of the generate
* tag, or, if no src tag present, using attr-name parameter.
* <p>
* This generator has 2 parameters:
* <ul>
* <li><code>attr-name</code> : the session attribute name (mandatory if no src
* attribute specified).
* </li>
* <li><code>root-element</code> (optional) : the name of the root element of the
* produced document. This parameter is optional if the session attribute is
* a DOM or an <code>XMLizable</code>.
* </li>
* </ul>
* <p>
* Example usage :
* <pre>
* <map:generator name="session-attr" logger="sitemap.generator.session-attr"
* src="org.apache.cocoon.generation.SessionAttributeGenerator"/>
* ...
* <map:generate type="session-attr">
* <map:parameter name="attr-name" value="myAttribute"/>
* <map:parameter name="root-element" value="root"/>
* </map:generate>
* </pre>
*
* @see org.apache.cocoon.transformation.ReadDOMSessionTransformer
* @see org.apache.cocoon.transformation.WriteDOMSessionTransformer
* @author <a href="mailto:cedric.damioli@anyware-tech.com">Cédric Damioli</a>
* @author <a href="mailto:sylvain@apache.org">Sylvain Wallez</a>
* @version CVS $Id: SessionAttributeGenerator.java,v 1.4 2004/03/05 13:02:55 bdelacretaz Exp $
*/
public class SessionAttributeGenerator extends AbstractGenerator {
public static final String ATTR_NAME = "attr-name";
public static final String ELEMENT_NAME = "root-element";
/** The object to generate */
private Object attrObject;
/** The element name */
private String elementName;
/**
* Setup the file generator :try to retrieve the session attribute given as sitemap parameter
*/
public void setup(SourceResolver resolver, Map objectModel, String src, Parameters par)
throws ProcessingException, SAXException, IOException {
super.setup(resolver, objectModel, src, par);
// Get the element name (can be null if the object is a DOM or an XMLizable)
this.elementName = par.getParameter(ELEMENT_NAME, null);
// Get the attribute name
String attrName = par.getParameter(ATTR_NAME, src);
if (attrName == null) {
String msg = "SessionAttributeGenerator needs an attribute name !";
getLogger().error(msg);
throw new ProcessingException(msg);
}
// Get the object to stream
Request request = ObjectModelHelper.getRequest(objectModel);
Session session = request.getSession(false);
if (session != null) {
this.attrObject = session.getAttribute(attrName);
}
// Controls
if (this.attrObject == null) {
if (this.elementName == null) {
// Can't generate nothing...
String msg = "Session attribute '" + attrName + "' doesn't exist";
getLogger().error(msg);
throw new ProcessingException(msg);
} else {
if (getLogger().isDebugEnabled()) {
getLogger().debug("Session attribute '" + attrName +
"' doesn't exist : will generate a single '" + this.elementName +
"' element.");
}
}
} else {
// Need an element name for non-xml objects
if (this.elementName == null &&
! (this.attrObject instanceof XMLizable) &&
! (this.attrObject instanceof Node)) {
String msg = "Session attribute '" + attrName + "' needs an enclosing element : class is " +
this.attrObject.getClass().getName();
getLogger().warn(msg);
throw new ProcessingException(msg);
}
}
}
/**
* Generate XML data
*/
public void generate() throws IOException, SAXException, ProcessingException {
xmlConsumer.startDocument();
if (this.elementName != null) {
xmlConsumer.startElement("", this.elementName, this.elementName, new AttributesImpl());
XMLUtils.valueOf(new IncludeXMLConsumer(xmlConsumer), this.attrObject);
xmlConsumer.endElement("", this.elementName, this.elementName);
} else {
XMLUtils.valueOf(new IncludeXMLConsumer(xmlConsumer), this.attrObject);
}
xmlConsumer.endDocument();
}
}