qdccrosswalk.java

dspace 用j2ee架构的一个数字图书馆.开源程序

     *
     *  dc.coverage.temporal = <dcterms:temporal />
     */
    private void init()
        throws CrosswalkException, IOException
    {
        if (inited)
            return;
        inited = true;

        myName = getPluginInstanceName();
        if (myName == null)
            throw new CrosswalkInternalException("Cannot determine plugin name, "+
                       "You must use PluginManager to instantiate QDCCrosswalk so the instance knows its name.");

        // grovel DSpace configuration for namespaces
        List nsList = new ArrayList();
        Enumeration pe = ConfigurationManager.propertyNames();
        String propname = CONFIG_PREFIX + ".namespace."+ myName +".";
        while (pe.hasMoreElements())
        {
            String key = (String)pe.nextElement();
            if (key.startsWith(propname))
                nsList.add(Namespace.getNamespace(key.substring(propname.length()),
                             ConfigurationManager.getProperty(key)));
        }
        nsList.add(Namespace.XML_NAMESPACE);
        namespaces = (Namespace[])nsList.toArray(new Namespace[nsList.size()]);

        // get XML schemaLocation fragment from config
        schemaLocation = ConfigurationManager.getProperty(CONFIG_PREFIX + ".schemaLocation."+ myName);

        // read properties
        String cmPropName = CONFIG_PREFIX+".properties."+myName;
        String propsFilename = ConfigurationManager.getProperty(cmPropName);
        if (propsFilename == null)
            throw new CrosswalkInternalException("Configuration error: "+
                "No properties file configured for QDC crosswalk named \""+myName+"\"");

        String parent = ConfigurationManager.getProperty("dspace.dir") +
            File.separator + "config" + File.separator;
        File propsFile = new File(parent, propsFilename);
        Properties qdcProps = new Properties();
        qdcProps.load(new FileInputStream(propsFile));

        // grovel properties to initialize qdc->element and element->qdc maps.
        // evaluate the XML fragment with a wrapper including namespaces.
        String postlog = "</wrapper>";
        StringBuffer prologb = new StringBuffer("<wrapper");
        for (int i = 0; i < namespaces.length; ++i)
        {
            prologb.append(" xmlns:");
            prologb.append(namespaces[i].getPrefix());
            prologb.append("=\"");
            prologb.append(namespaces[i].getURI());
            prologb.append("\"");
        }
        prologb.append(">");
        String prolog = prologb.toString();
        pe = qdcProps.propertyNames();
        while (pe.hasMoreElements())
        {
            String qdc = (String)pe.nextElement();
            String val = qdcProps.getProperty(qdc);
            try
            {
                Document d = builder.build(new StringReader(prolog+val+postlog));
                Element element = (Element)d.getRootElement().getContent(0);
                qdc2element.put(qdc, element);
                element2qdc.put(makeQualifiedTagName(element), qdc);
                log.debug("Building Maps: qdc=\""+qdc+"\", element=\""+element.toString()+"\"");
            }
            catch (org.jdom.JDOMException je)
            {
                throw new CrosswalkInternalException("Failed parsing XML fragment in properties file: \""+prolog+val+postlog+"\": "+je.toString());
            }
        }
    }

    public Namespace[] getNamespaces()
    {
        try
        {
            init();
        }
        catch (Exception e)
        {
        }
        return namespaces;
    }

    public String getSchemaLocation()
    {
        try
        {
            init();
        }
        catch (Exception e)
        {
        }
        return schemaLocation;
    }

    /**
     * Returns object's metadata in MODS format, as XML structure node.
     */
    public List disseminateList(DSpaceObject dso)
        throws CrosswalkException,
               IOException, SQLException, AuthorizeException
    {
        if (dso.getType() != Constants.ITEM)
            throw new CrosswalkObjectNotSupported("QDCCrosswalk can only crosswalk an Item.");
        Item item = (Item)dso;
        init();

        DCValue[] dc = item.getMetadata(Item.ANY, Item.ANY, Item.ANY, Item.ANY);
        List result = new ArrayList(dc.length);
        for (int i = 0; i < dc.length; i++)
        {
            // Compose qualified DC name - schema.element[.qualifier]
            // e.g. "dc.title", "dc.subject.lcc", "lom.Classification.Keyword"
            String qdc = dc[i].schema+"."+
                         ((dc[i].qualifier == null) ? dc[i].element
                            : (dc[i].element + "." + dc[i].qualifier));

            Element elt = (Element)qdc2element.get(qdc);

            // only complain about missing elements in the DC schema:
            if (elt == null)
            {
                if (dc[i].schema.equals(MetadataSchema.DC_SCHEMA))
                    log.warn("WARNING: "+myName+": No QDC mapping for \"" + qdc+"\"");
            }
            else
            {
                Element qe = (Element)elt.clone();
                qe.setText(dc[i].value);
                if (dc[i].language != null)
                    qe.setAttribute("lang", dc[i].language, Namespace.XML_NAMESPACE);
                result.add(qe);
            }
        }
        return result;
    }

    public Element disseminateElement(DSpaceObject dso)
        throws CrosswalkException,
               IOException, SQLException, AuthorizeException
    {
        Element root = new Element("qualifieddc", DCTERMS_NS);
        root.addContent(disseminateList(dso));
        return root;
    }

    public boolean canDisseminate(DSpaceObject dso)
    {
        return true;
    }

    public void ingest(Context context, DSpaceObject dso, Element root)
        throws CrosswalkException, IOException, SQLException, AuthorizeException
    {
        init();

        // NOTE:  don't bother comparing namespace on root element
        // because DCMI doesn't specify one, and every app uses its
        // own..  just give up in the face of this madness and accept
        // anything with the right name.
        if (!(root.getName().equals("qualifieddc")))
            throw new MetadataValidationException("Wrong root element for Qualified DC: "+root.toString());
        ingest(context, dso, root.getChildren());
    }

    public void ingest(Context context, DSpaceObject dso, List ml)
        throws CrosswalkException, IOException, SQLException, AuthorizeException
    {
        init();

        // for now, forget about any targets but item.
        if (dso.getType() != Constants.ITEM)
            throw new CrosswalkInternalException("Wrong target object type, QDCCrosswalk can only crosswalk to an Item.");

        Item item = (Item)dso;

        Iterator mi = ml.iterator();
        while (mi.hasNext())
        {
            Element me = (Element)mi.next();
            String key = makeQualifiedTagName(me);

            // if the root element gets passed here, recurse:
            if (me.getName().equals("qualifieddc"))
                ingest(context, dso, me.getChildren());

            else if (element2qdc.containsKey(key))
            {
                String qdc[] = ((String)element2qdc.get(key)).split("\\.");

                // get language - prefer xml:lang, accept lang.
                String lang = me.getAttributeValue("lang", Namespace.XML_NAMESPACE);
                if (lang == null)
                    lang = me.getAttributeValue("lang");

                if (qdc.length == 3)
                    item.addMetadata(qdc[0], qdc[1], qdc[2], lang, me.getText());
                else if (qdc.length == 2)
                    item.addMetadata(qdc[0], qdc[1], null,   lang, me.getText());
                else
                    throw new CrosswalkInternalException("Unrecognized format in QDC element identifier for key=\""+key+"\", qdc=\""+(String)element2qdc.get(key)+"\"");
            }
            else
                log.warn("WARNING: "+myName+": No mapping for Element=\"" + key+"\" to qdc.");
        }
    }

    public boolean preferList()
    {
        return true;
    }
}