/**
* The contents of this file are subject to the license and copyright
* detailed in the LICENSE and NOTICE files at the root of the source
* tree and available online at
*
* http://www.dspace.org/license/
*/
package org.dspace.app.xmlui.wing.element;
import java.util.ArrayList;
import java.util.List;
import org.dspace.app.xmlui.wing.Message;
import org.dspace.app.xmlui.wing.WingConstants;
import org.dspace.app.xmlui.wing.WingContext;
import org.dspace.app.xmlui.wing.WingException;
import org.xml.sax.Attributes;
import org.xml.sax.ContentHandler;
import org.xml.sax.SAXException;
import org.xml.sax.ext.LexicalHandler;
import org.xml.sax.helpers.NamespaceSupport;
/**
* A class representing a set of metadata about the page being generated.
*
* @author Scott Phillips
*/
public class PageMeta extends AbstractWingElement implements
WingMergeableElement, MetadataElement
{
/** Name of the pageMeta element */
public static final String E_PAGE_META = "pageMeta";
/** Has this PageMeta element been merged? */
private boolean merged = false;
/**
* A page meta may hold two types of elements, trails or
* metadata. Each of these types are seperated so that
* we can search through each time as we merge documents.
*/
private List<Metadata> metadatum = new ArrayList<Metadata>();
private List<Trail> trails = new ArrayList<Trail>();
/**
* Construct a new pageMeta
*
* @param context
* (Required) The context this element is contained in, such as
* where to route SAX events and what i18n catalogue to use.
*/
protected PageMeta(WingContext context) throws WingException
{
super(context);
}
/**
* Add metadata about this page.
*
* @param element
* (Required) The metadata element.
* @param qualifier
* (May be null) The metadata qualifier.
* @param language
* (May be null) The metadata's language
* @param allowMultiple
* (Required) determine if multipe metadata element with the same
* element, qualifier and language are allowed.
* @return A new metadata
*/
public Metadata addMetadata(String element, String qualifier,
String language, boolean allowMultiple) throws WingException
{
Metadata metadata = new Metadata(context, element, qualifier, language, allowMultiple);
metadatum.add(metadata);
return metadata;
}
/**
* Add metadata about this page.
*
* @param element
* (Required) The metadata element.
* @param qualifier
* (May be null) The metadata qualifier.
* @param language
* (May be null) The metadata's language
* @return A new metadata
*/
public Metadata addMetadata(String element, String qualifier, String language)
throws WingException
{
return addMetadata(element, qualifier, language, false);
}
/**
* Add metadata about this page.
*
* @param element
* (Required) The metadata element.
* @param qualifier
* (May be null) The metadata qualifier.
* @return A new metadata
*/
public Metadata addMetadata(String element, String qualifier)
throws WingException
{
return addMetadata(element, qualifier, null, false);
}
/**
* Add metadata about this page.
*
* @param element
* (Required) The metadata element.
* @return A new metadata
*/
public Metadata addMetadata(String element) throws WingException
{
return addMetadata(element, null, null, false);
}
/**
* Add a new trail to the page.
*
* @param target
* (May be null) Target URL for this trail item.
* @param rend
* (May be null) special rendering instructions
* @return a new trail
*/
public Trail addTrail(String target, String rend)
throws WingException
{
Trail trail = new Trail(context, target, rend);
trails.add(trail);
return trail;
}
/**
* Add a new trail to the page without a link or render attribute.
*
* @return a new trail
*/
public Trail addTrail()
throws WingException
{
return addTrail(null,null);
}
/**
* Add a new trail link to the page.
*
* @param target
* (May be null) The Target URL for this trail item.
* @param characters
* (May be null) The textual contents of this trail item.
*/
public void addTrailLink(String target, String characters)
throws WingException
{
Trail trail = addTrail(target, null);
trail.addContent(characters);
}
/**
* Add a new trail link to the page.
*
* @param target
* (May be null) The Target URL for this trail item.
* @param message
* (Required) The textual contents of this trail item to be
* translated
*/
public void addTrailLink(String target, Message message)
throws WingException
{
Trail trail = addTrail(target, null);
trail.addContent(message);
}
/**
* Determine if the given SAX event is a PageMeta element.
*
* @param namespace
* The element's name space
* @param localName
* The local, unqualified, name for this element
* @param qName
* The qualified name for this element
* @param attributes
* The element's attributes
* @return True if this WingElement is equivalent to the given SAX Event.
*/
public boolean mergeEqual(String namespace, String localName, String qName,
Attributes attributes) throws SAXException, WingException
{
if (!WingConstants.DRI.URI.equals(namespace))
{
return false;
}
if (!E_PAGE_META.equals(localName))
{
return false;
}
return true;
}
/**
* Since metadata can not be merged there are no mergeable children. This
* just return's null.
*
* @param namespace
* The element's name space
* @param localName
* The local, unqualified, name for this element *
* @param qName
* The qualified name for this element
* @param attributes
* The element's attributes
* @return The child element
*/
public WingMergeableElement mergeChild(String namespace, String localName,
String qName, Attributes attributes) throws SAXException,
WingException
{
// We don't merge our children but we do have one special optimization,
// if a metadata or trail is allready in the document then we do not add
// our own trail or metadata for that particular item.
if (WingConstants.DRI.URI.equals(namespace) && Trail.E_TRAIL.equals(localName))
{
for (Trail trail : trails)
{
trail.dispose();
}
trails.clear();
}
if (WingConstants.DRI.URI.equals(namespace) && Metadata.E_METADATA.equals(localName))
{
String element = attributes.getValue(Metadata.A_ELEMENT);
String qualifier = attributes.getValue(Metadata.A_QUALIFIER);
String language = attributes.getValue(Metadata.A_LANGUAGE);
List<Metadata> remove = new ArrayList<Metadata>();
for (Metadata metadata : metadatum)
{
if (metadata.equals(element,qualifier,language) && !metadata.allowMultiple())
{
remove.add(metadata);
}
}
// Remove all the metadata elements we found.
for (Metadata metadata : remove)
{
metadata.dispose();
metadatum.remove(metadata);
}
}
return null;
}
/**
* Inform this element that it is being merged with an existing element.
*/
public Attributes merge(Attributes attributes) throws SAXException,
WingException
{
this.merged = true;
return attributes;
}
/**
* Translate this element into SAX events.
*
* @param contentHandler
* (Required) The registered contentHandler where SAX events
* should be routed too.
* @param lexicalHandler
* (Required) The registered lexicalHandler where lexical
* events (such as CDATA, DTD, etc) should be routed too.
* @param namespaces
* (Required) SAX Helper class to keep track of namespaces able
* to determine the correct prefix for a given namespace URI.
*/
public void toSAX(ContentHandler contentHandler, LexicalHandler lexicalHandler,
NamespaceSupport namespaces) throws SAXException
{
if (!merged)
{
startElement(contentHandler, namespaces, E_PAGE_META, null);
}
for (Metadata metadata : metadatum)
{
metadata.toSAX(contentHandler, lexicalHandler, namespaces);
}
for (Trail trail : trails)
{
trail.toSAX(contentHandler, lexicalHandler, namespaces);
}
if (!merged)
{
endElement(contentHandler, namespaces, E_PAGE_META);
}
}
/**
* dispose
*/
public void dispose()
{
for (Metadata metadata : metadatum)
{
metadata.dispose();
}
for (Trail trail : trails)
{
trail.dispose();
}
trails.clear();
trails = null;
metadatum.clear();
metadatum = null;
super.dispose();
}
}