dspaceoaicatalog.java

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     */
    public Map listIdentifiers(String resumptionToken)
            throws BadResumptionTokenException, OAIInternalServerError
    {
        // Resumption tokens not yet supported
        throw new BadResumptionTokenException();
    }

    /**
     * Retrieve the specified metadata for the specified identifier
     * 
     * @param identifier
     *            the OAI identifier
     * @param metadataPrefix
     *            the OAI metadataPrefix
     * @return the <record/>portion of the XML response.
     * @exception OAIInternalServerError
     *                signals an http status code 500 problem
     * @exception CannotDisseminateFormatException
     *                the metadataPrefix is not supported by the item.
     * @exception IdDoesNotExistException
     *                the identifier wasn't found
     */
    public String getRecord(String identifier, String metadataPrefix)
            throws OAIInternalServerError, CannotDisseminateFormatException,
            IdDoesNotExistException
    {
        log
                .info(LogManager.getHeader(null, "oai_request",
                        "verb=getRecord,identifier="
                                + ((identifier == null) ? "null" : identifier)
                                + ",metadataPrefix="
                                + ((metadataPrefix == null) ? "null"
                                        : metadataPrefix)));

        Context context = null;
        String record = null;
        HarvestedItemInfo itemInfo = null;
        
        // First get the item from the DB
        try
        {
            // Valid IDs start with oai:hostname:
            if (identifier.startsWith(OAI_ID_PREFIX))
            {
                context = new Context();

                /*
                 * Try and get the item. the .substring() is to strip the
                 * oai:(hostname): prefix to get the raw handle
                 */
                itemInfo = Harvest.getSingle(context, identifier
                        .substring(OAI_ID_PREFIX.length()), true);
            }

            if (itemInfo == null)
            {
                log.info(LogManager.getHeader(null, "oai_error",
                        "id_does_not_exist"));
                throw new IdDoesNotExistException(identifier);
            }

            String schemaURL;

            if ((schemaURL = getCrosswalks().getSchemaURL(metadataPrefix)) == null)
            {
                log.info(LogManager.getHeader(null, "oai_error",
                        "cannot_disseminate_format"));
                throw new CannotDisseminateFormatException(metadataPrefix);
            }

            record = getRecordFactory().create(itemInfo, schemaURL,
                    metadataPrefix);
        }
        catch (SQLException se)
        {
            // Log the error
            log.warn(LogManager.getHeader(context, "database_error", ""), se);

            throw new OAIInternalServerError(se.toString());
        }
        finally
        {
            if (context != null)
            {
                context.abort();
            }
        }

        return record;
    }

    /**
     * Retrieve a list of records that satisfy the specified criteria. Note,
     * though, that unlike the other OAI verb type methods implemented here,
     * both of the listRecords methods are already implemented in
     * AbstractCatalog rather than abstracted. This is because it is possible to
     * implement ListRecords as a combination of ListIdentifiers and GetRecord
     * combinations. Nevertheless, I suggest that you override both the
     * AbstractCatalog.listRecords methods here since it will probably improve
     * the performance if you create the response in one fell swoop rather than
     * construct it one GetRecord at a time.
     * 
     * @param from
     *            beginning date using the proper granularity
     * @param until
     *            ending date using the proper granularity
     * @param set
     *            the set name or null if no such limit is requested
     * @param metadataPrefix
     *            the OAI metadataPrefix or null if no such limit is requested
     * @return a Map object containing entries for a "records" Iterator object
     *         (containing XML <record/>Strings) and an optional
     *         "resumptionMap" Map.
     * @exception OAIInternalServerError
     *                signals an http status code 500 problem
     * @exception NoSetHierarchyException
     *                The repository doesn't support sets.
     * @exception CannotDisseminateFormatException
     *                the metadataPrefix isn't supported by the item.
     */
    public Map listRecords(String from, String until, String set,
            String metadataPrefix) throws OAIInternalServerError,
            NoSetHierarchyException, CannotDisseminateFormatException,
            NoItemsMatchException, BadArgumentException
    {
        log
                .info(LogManager.getHeader(null, "oai_request",
                        "verb=listRecords,from="
                                + ((from == null) ? "null" : from)
                                + ",until="
                                + ((until == null) ? "null" : until)
                                + ",set="
                                + ((set == null) ? "null" : set)
                                + ",metadataPrefix="
                                + ((metadataPrefix == null) ? "null"
                                        : metadataPrefix)));

        Map m = doRecordHarvest(from, until, set, metadataPrefix, 0);

        // Null means bad metadata prefix was bad
        if (m == null)
        {
            log.info(LogManager.getHeader(null, "oai_error",
                    "cannot_disseminate_format"));
            throw new CannotDisseminateFormatException(metadataPrefix);
        }

        // If there were zero results, return the appropriate error
        Iterator i = (Iterator) m.get("records");

        if ((i == null) || !i.hasNext())
        {
            log.info(LogManager.getHeader(null, "oai_error", "no_items_match"));
            throw new NoItemsMatchException();
        }

        return m;
    }

    /**
     * Retrieve the next set of records associated with the resumptionToken
     * 
     * @param resumptionToken
     *            implementation-dependent format taken from the previous
     *            listRecords() Map result.
     * @return a Map object containing entries for "headers" and "identifiers"
     *         Iterators (both containing Strings) as well as an optional
     *         "resumptionMap" Map.
     * @exception OAIInternalServerError
     *                signals an http status code 500 problem
     * @exception BadResumptionTokenException
     *                the value of the resumptionToken argument is invalid or
     *                expired.
     */
    public Map listRecords(String resumptionToken)
            throws BadResumptionTokenException, OAIInternalServerError
    {
        log.info(LogManager.getHeader(null, "oai_request",
                "verb=listRecords,resumptionToken=" + resumptionToken));

        /*
         * FIXME: This may return zero records if the previous harvest returned
         * a number of records that's an exact multiple of MAX_RECORDS. I hope
         * that's OK.
         */
        Object[] params = decodeResumptionToken(resumptionToken);
        Integer offset = (Integer) params[4];

        Map m = null;

        /*
         * We catch BadArgumentExceptions here, because doRecordHarvest() throws
         * BadArgumentExcpetions when the set spec is bad. set spec bad == bad
         * resumption token.
         */
        try
        {
            m = doRecordHarvest((String) params[0], (String) params[1],
                    (String) params[2], (String) params[3], offset.intValue());
        }
        catch (BadArgumentException bae)
        {
            m = null;
        }

        // null result means a problem -> bad resumption token
        if (m == null)
        {
            log.info(LogManager.getHeader(null, "oai_error",
                    "bad_resumption_token"));
            throw new BadResumptionTokenException();
        }

        return m;
    }

    /**
     * Method to do the actual harvest of records
     * 
     * @param from
     *            OAI 'from' parameter
     * @param until
     *            OAI 'until' parameter
     * @param set
     *            OAI 'set' parameter
     * @param metadataPrefix
     *            OAI 'metadataPrefix' parameter
     * @param offset
     *            where to start this harvest
     * 
     * @return the Map for listRecords to return, or null if the metadataPrefix
     *         is invalid
     */
    private Map doRecordHarvest(String from, String until, String set,
            String metadataPrefix, int offset) throws OAIInternalServerError,
            BadArgumentException
    {
        Context context = null;
        String schemaURL = getCrosswalks().getSchemaURL(metadataPrefix);
        Map results = new HashMap();

        if (schemaURL == null)
        {
            return null;
        }

        // List to put results in
        List records = new LinkedList();

        try
        {
            context = new Context();

            // Get the relevant HarvestedItemInfo objects to make headers
            Collection scope = resolveSet(context, set);
            List itemInfos = Harvest.harvest(context, scope, from, until,
                    offset, MAX_RECORDS, // Limit amount returned from one
                                         // request
                    true, true, true); // Need items, containers + withdrawals

            // Build list of XML records from item info objects
            Iterator i = itemInfos.iterator();

            while (i.hasNext())
            {
                HarvestedItemInfo itemInfo = (HarvestedItemInfo) i.next();

                try
                {
                    String recordXML = getRecordFactory().create(itemInfo,
                            schemaURL, metadataPrefix);
                    records.add(recordXML);
                }
                catch (CannotDisseminateFormatException cdfe)
                {
                    /*
                     * FIXME: I've a feeling a
                     * "CannotDisseminateFormatException" should be discarded
                     * here - it's OK if some records in the requested date
                     * range don't have the requested metadata format available.
                     * I'll just log it for now.
                     */
                    if (log.isDebugEnabled())
                    {
                        log.debug(LogManager.getHeader(context, "oai_warning",
                                "Couldn't disseminate " + metadataPrefix
                                        + " for " + itemInfo.handle));
                    }
                }
            }

            // Put results in form needed to return
            results.put("records", records.iterator());

            log.info(LogManager.getHeader(context, "oai_harvest", "results="
                    + records.size()));

            // If we have MAX_RECORDS records, we need to provide a resumption