Package org.dspace.content.crosswalk

Class 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 Detail

      • AIPDIMCrosswalk

        public AIPDIMCrosswalk()

    • Method Detail

      • 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

      • 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