dspaceoaicatalog.java

dspace 用j2ee架构的一个数字图书馆.开源程序

            // token
            if (records.size() >= MAX_RECORDS)
            {
                String resumptionToken = makeResumptionToken(from, until, set,
                        metadataPrefix, offset + MAX_RECORDS);

                if (log.isDebugEnabled())
                {
                    log.debug(LogManager
                            .getHeader(context, "made_resumption_token",
                                    "token=" + resumptionToken));
                }

                results.put("resumptionMap", getResumptionMap(resumptionToken));

                //results.put("resumptionToken", resumptionToken);
            }
        }
        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 results;
    }

    /**
     * Retrieve a list of sets that satisfy the specified criteria
     * 
     * @return a Map object containing "sets" Iterator object (contains
     *         <setSpec/>XML Strings) as well as an optional resumptionMap Map.
     * @exception OAIBadRequestException
     *                signals an http status code 400 problem
     * @exception OAIInternalServerError
     *                signals an http status code 500 problem
     */
    public Map listSets() throws NoSetHierarchyException,
            OAIInternalServerError
    {
        log.info(LogManager.getHeader(null, "oai_request", "verb=listSets"));

        Context context = null;

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

        try
        {
            context = new Context();

            Collection[] allCols = Collection.findAll(context);
            StringBuffer spec = null;
            for (int i = 0; i < allCols.length; i++)
            {
                spec = new StringBuffer("<set><setSpec>hdl_");
                spec.append(allCols[i].getHandle().replace('/', '_'));
                spec.append("</setSpec>");
                String collName = allCols[i].getMetadata("name");
                if(collName != null)
                {
                	spec.append("<setName>");
                	spec.append(Utils.addEntities(collName));
                	spec.append("</setName>");
                }
                else
                {
                	spec.append("<setName />");
                    // Warn that there is an error of a null set name
                	log.info(LogManager.getHeader(null, "oai_error",
                			       "null_set_name_for_set_id_" + allCols[i].getHandle()));
                }
                spec.append("</set>");
                sets.add(spec.toString());
            }
        }
        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();
            }
        }

        // Put results in form needed to return
        Map results = new HashMap();
        results.put("sets", sets.iterator());

        return results;
    }

    /**
     * Retrieve the next set of sets associated with the resumptionToken
     * 
     * @param resumptionToken
     *            implementation-dependent format taken from the previous
     *            listSets() Map result.
     * @return a Map object containing "sets" Iterator object (contains
     *         <setSpec/>XML Strings) as well as an optional resumptionMap Map.
     * @exception BadResumptionTokenException
     *                the value of the resumptionToken is invalid or expired.
     * @exception OAIInternalServerError
     *                signals an http status code 500 problem
     */
    public Map listSets(String resumptionToken)
            throws BadResumptionTokenException, OAIInternalServerError
    {
        // Resumption tokens not yet supported
        throw new BadResumptionTokenException();
    }

    /**
     * close the repository
     */
    public void close()
    {
    }

    // ******************************************
    // Internal DSpace utility methods below here
    // ******************************************

    /**
     * Get the community or collection signified by a set spec
     * 
     * @param context
     *            DSpace context object
     * @param set
     *            OAI set spec
     * @return the corresponding community or collection, or null if no set
     *         provided
     */
    private Collection resolveSet(Context context, String set)
            throws SQLException, BadArgumentException
    {
        if (set == null)
        {
            return null;
        }

        DSpaceObject o = null;

        /*
         * set specs are in form hdl_123.456_789 corresponding to
         * hdl:123.456/789
         */
        if (set.startsWith("hdl_"))
        {
            // Looks OK so far... turn second _ into /
            String handle = set.substring(4).replace('_', '/');
            o = HandleManager.resolveToObject(context, handle);
        }

        // If it corresponds to a collection, that's the set we want
        if ((o != null) && o instanceof Collection)
        {
            return (Collection) o;
        }

        // Handle is either non-existent, or corresponds to a non-collection
        // Either way, a bad set spec, ergo a bad argument
        throw new BadArgumentException();
    }

    /**
     * Create a resumption token. The relevant parameters for the harvest are
     * put in a
     * 
     * @param from
     *            OAI 'from' parameter
     * @param until
     *            OAI 'until' parameter
     * @param set
     *            OAI 'set' parameter
     * @param prefix
     *            OAI 'metadataPrefix' parameter
     * @param offset
     *            where to start the next harvest
     * 
     * @return the appropriate resumption token
     */
    private String makeResumptionToken(String from, String until, String set,
            String prefix, int offset)
    {
        StringBuffer token = new StringBuffer();

        if (from != null)
        {
            token.append(from);
        }

        token.append("/");

        if (until != null)
        {
            token.append(until);
        }

        token.append("/");

        if (set != null)
        {
            token.append(set);
        }

        token.append("/");

        if (prefix != null)
        {
            token.append(prefix);
        }

        token.append("/");
        token.append(String.valueOf(offset));

        return (token.toString());
    }

    /**
     * Get the information out of a resumption token
     * 
     * @param token
     *            the resumption token
     * @return a 5-long array of Objects; 4 Strings (from, until, set, prefix)
     *         and an Integer (the offset)
     */
    private Object[] decodeResumptionToken(String token)
            throws BadResumptionTokenException
    {
        Object[] obj = new Object[5];
        StringTokenizer st = new StringTokenizer(token, "/", true);

        try
        {
            // Extract from, until, set, prefix
            for (int i = 0; i < 4; i++)
            {
                if (!st.hasMoreTokens())
                {
                    throw new BadResumptionTokenException();
                }

                String s = st.nextToken();

                // If this value is a delimiter /, we have no value for this
                // part
                // of the resumption token.
                if (s.equals("/"))
                {
                    obj[i] = null;
                }
                else
                {
                    obj[i] = s;

                    // Skip the delimiter
                    st.nextToken();
                }

                log.debug("is: " + (String) obj[i]);
            }

            if (!st.hasMoreTokens())
            {
                throw new BadResumptionTokenException();
            }

            obj[4] = new Integer(st.nextToken());
        }
        catch (NumberFormatException nfe)
        {
            throw new BadResumptionTokenException();
        }
        catch (NoSuchElementException nsee)
        {
            throw new BadResumptionTokenException();
        }

        return obj;
    }
}