Package org.dspace.content.crosswalk

Class AIPDIMCrosswalk

java.lang.Object
org.dspace.content.crosswalk.AIPDIMCrosswalk
All Implemented Interfaces:
DisseminationCrosswalk, IngestionCrosswalk
public class AIPDIMCrosswalk extends Object implements DisseminationCrosswalk, IngestionCrosswalk
Crosswalk descriptive metadata to and from DIM (DSpace Intermediate Metadata) format, strictly for the purpose of including a precise and complete record of the DMD in an AIP. Although the DIM format was never intended to be used outside of DSpace, it is admirably suited to describing the exact state of the descriptive MD stored in the RDBMS. All crosswalks to standard formats such as MODS and even DC are necessarily "lossy" and inexact. Since the purpose of an AIP is to preserve and restore the state of an object exactly, DIM is the preferred format for recording its descriptive MD.

In order to allow external applications to make sense of DSpace AIPs for preservation purposes, we recommend adding a parallel descriptive metadata section in one of the preferred standard formats such as MODS as well as the DIM.

Version:
$Revision: 1.2 $
Author:
Larry Stone

  • Constructor Details

    • AIPDIMCrosswalk

      public AIPDIMCrosswalk()

  • Method Details

    • getNamespaces

      public org.jdom2.Namespace[] getNamespaces()
      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()
      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.

    • canDisseminate

      public boolean canDisseminate(DSpaceObject dso)
      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()
      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().

    • disseminateList

      public List<org.jdom2.Element> disseminateList(Context context, DSpaceObject dso) throws CrosswalkException, IOException, SQLException, AuthorizeException
      Execute crosswalk, returning List of XML elements. Returns a List of JDOM Element objects representing the XML produced by the crosswalk. This is typically called when a list of fields is desired, e.g. for embedding in a METS document xmlData field.

      When there are no results, an empty list is returned, but never null.

      Specified by:
      disseminateList in interface DisseminationCrosswalk
      Parameters:
      context - context
      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.
      CrosswalkInternalException - (CrosswalkException) failure of the crosswalk itself.
      CrosswalkObjectNotSupported - (CrosswalkException) Cannot crosswalk this kind of DSpace object.
      CrosswalkException

    • disseminateElement

      public org.jdom2.Element disseminateElement(Context context, DSpaceObject dso) throws CrosswalkException, IOException, SQLException, AuthorizeException
      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:
      context - context
      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.
      CrosswalkInternalException - (CrosswalkException) failure of the crosswalk itself.
      CrosswalkObjectNotSupported - (CrosswalkException) Cannot crosswalk this kind of DSpace object.
      CrosswalkException

    • ingest

      public void ingest(Context context, DSpaceObject dso, org.jdom2.Element root, boolean createMissingMetadataFields) throws CrosswalkException, IOException, SQLException, AuthorizeException
      Ingest a whole document. Build Document object around root element, and feed that to the transformation, since it may get handled differently than a List of metadata elements.
      Specified by:
      ingest in interface IngestionCrosswalk
      Parameters:
      createMissingMetadataFields - whether to create missing fields
      context - DSpace context.
      dso - DSpace Object (usually an Item) to which new metadata gets attached.
      root - root Element of metadata document.
      Throws:
      CrosswalkException - if crosswalk error
      IOException - if IO error
      SQLException - if database error
      AuthorizeException - if authorization error

    • ingest

      public void ingest(Context context, DSpaceObject dso, List<org.jdom2.Element> dimList, boolean createMissingMetadataFields) throws CrosswalkException, IOException, SQLException, AuthorizeException
      Fields correspond directly to Item.addMetadata() calls so they are simply executed.
      Specified by:
      ingest in interface IngestionCrosswalk
      Parameters:
      createMissingMetadataFields - whether to create missing fields
      dimList - List of elements
      context - DSpace context.
      dso - DSpace Object (Item, Bitstream, etc) to which new metadata gets attached.
      Throws:
      CrosswalkException - if crosswalk error
      IOException - if IO error
      SQLException - if database error
      AuthorizeException - if authorization error