org.dspace.content.crosswalk
Class MODSDisseminationCrosswalk

java.lang.Object
  extended by org.dspace.core.SelfNamedPlugin
      extended by org.dspace.content.crosswalk.MODSDisseminationCrosswalk
All Implemented Interfaces:
DisseminationCrosswalk

public class MODSDisseminationCrosswalk
extends SelfNamedPlugin
implements DisseminationCrosswalk

Configurable MODS Crosswalk

This class supports multiple dissemination crosswalks from DSpace internal data to the MODS XML format (see http://www.loc.gov/standards/mods/.)

It registers multiple Plugin names, which it reads from the DSpace configuration as follows:

Configuration

Every key starting with "crosswalk.mods.properties." describes a MODS crosswalk. Everything after the last period is the plugin name, and the value is the pathname (relative to dspace.dir/config) of the crosswalk configuration file.

You can have two names point to the same crosswalk, just add two configuration entries with the same value, e.g.

    crosswalk.mods.properties.MODS = crosswalks/mods.properties
    crosswalk.mods.properties.default = crosswalks/mods.properties
 
The first line creates a plugin with the name "MODS" which is configured from the file dspace-dir/config/crosswalks/mods.properties.

Since there is significant overhead in reading the properties file to configure the crosswalk, and a crosswalk instance may be used any number of times, we recommend caching one instance of the crosswalk for each name and simply reusing those instances. The PluginManager does this by default.

Version:
$Revision: 3761 $
Author:
Larry Stone

Field Summary
static org.jdom.Namespace MODS_NS
          MODS namespace.
static String MODS_XSD
          URL of MODS XML Schema
 
Fields inherited from interface org.dspace.content.crosswalk.DisseminationCrosswalk
XSI_NS
 
Constructor Summary
MODSDisseminationCrosswalk()
           
 
Method Summary
 boolean canDisseminate(DSpaceObject dso)
          Predicate: Can this disseminator crosswalk the given object.
 org.jdom.Element disseminateElement(DSpaceObject dso)
          Execute crosswalk, returning one XML root element as a JDOM Element object.
 List disseminateList(DSpaceObject dso)
          Returns object's metadata in MODS format, as List of XML structure nodes.
 org.jdom.Namespace[] getNamespaces()
          Get XML namespaces of the elements this crosswalk may return.
static String[] getPluginNames()
           
 String getSchemaLocation()
          Get the XML Schema location(s) of the target metadata format.
 boolean preferList()
          Predicate: Does this disseminator prefer to return a list of Elements, rather than a single root Element?
 
Methods inherited from class org.dspace.core.SelfNamedPlugin
getPluginInstanceName, setPluginInstanceName
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

MODS_NS

public static final org.jdom.Namespace MODS_NS
MODS namespace.


MODS_XSD

public static final String MODS_XSD
URL of MODS XML Schema

See Also:
Constant Field Values
Constructor Detail

MODSDisseminationCrosswalk

public MODSDisseminationCrosswalk()
Method Detail

getPluginNames

public static String[] getPluginNames()

getNamespaces

public org.jdom.Namespace[] getNamespaces()
Description copied from interface: DisseminationCrosswalk
Get XML namespaces of the elements this crosswalk may return. Returns the XML namespaces (as JDOM objects) of the root element.

Specified by:
getNamespaces in interface DisseminationCrosswalk
Returns:
array of namespaces, which may be empty.

getSchemaLocation

public String getSchemaLocation()
Description copied from interface: DisseminationCrosswalk
Get the XML Schema location(s) of the target metadata format. Returns the string value of the xsi:schemaLocation attribute that should be applied to the generated XML.

It may return the empty string if no schema is known, but crosswalk authors are strongly encouraged to implement this call so their output XML can be validated correctly.

Specified by:
getSchemaLocation in interface DisseminationCrosswalk
Returns:
SchemaLocation string, including URI namespace, followed by whitespace and URI of XML schema document, or empty string if unknown.

disseminateList

public List disseminateList(DSpaceObject dso)
                     throws CrosswalkException,
                            IOException,
                            SQLException,
                            AuthorizeException
Returns object's metadata in MODS format, as List of XML structure nodes.

Specified by:
disseminateList in interface DisseminationCrosswalk
Parameters:
dso - the DSpace Object whose metadata to export.
Returns:
results of crosswalk as list of XML elements.
Throws:
CrosswalkInternalException - (CrosswalkException) failure of the crosswalk itself.
CrosswalkObjectNotSupported - (CrosswalkException) Cannot crosswalk this kind of DSpace object.
IOException - I/O failure in services this calls
SQLException - Database failure in services this calls
AuthorizeException - current user not authorized for this operation.
CrosswalkException

disseminateElement

public org.jdom.Element disseminateElement(DSpaceObject dso)
                                    throws CrosswalkException,
                                           IOException,
                                           SQLException,
                                           AuthorizeException
Description copied from interface: DisseminationCrosswalk
Execute crosswalk, returning one XML root element as a JDOM Element object. This is typically the root element of a document.

Specified by:
disseminateElement in interface DisseminationCrosswalk
Parameters:
dso - the DSpace Object whose metadata to export.
Returns:
root Element of the target metadata, never null
Throws:
CrosswalkInternalException - (CrosswalkException) failure of the crosswalk itself.
CrosswalkObjectNotSupported - (CrosswalkException) Cannot crosswalk this kind of DSpace object.
IOException - I/O failure in services this calls
SQLException - Database failure in services this calls
AuthorizeException - current user not authorized for this operation.
CrosswalkException

canDisseminate

public boolean canDisseminate(DSpaceObject dso)
Description copied from interface: DisseminationCrosswalk
Predicate: Can this disseminator crosswalk the given object. Needed by OAI-PMH server implementation.

Specified by:
canDisseminate in interface DisseminationCrosswalk
Parameters:
dso - dspace object, e.g. an Item.
Returns:
true when disseminator is capable of producing metadata.

preferList

public boolean preferList()
Description copied from interface: DisseminationCrosswalk
Predicate: Does this disseminator prefer to return a list of Elements, rather than a single root Element?

Some metadata formats have an XML schema without a root element, for example, the Dublin Core and Qualified Dublin Core formats. This would be true for a crosswalk into QDC, since it would "prefer" to return a list, since any root element it has to produce would have to be part of a nonstandard schema. In most cases your implementation will want to return false

Specified by:
preferList in interface DisseminationCrosswalk
Returns:
true when disseminator prefers you call disseminateList().


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