gdataservice.java

一套java版本的搜索引擎源码

    }

    /**
     * @see org.apache.lucene.gdata.server.Service#getFeed(org.apache.lucene.gdata.server.GDataRequest,
     *      org.apache.lucene.gdata.server.GDataResponse)
     */
    @SuppressWarnings("unchecked")
    public BaseFeed getFeed(GDataRequest request, GDataResponse response)
            throws ServiceException {

        ServerBaseFeed feed = new ServerBaseFeed();
        feed.setId(request.getFeedId());
        feed.setStartIndex(request.getStartIndex());
        feed.setItemsPerPage(request.getItemsPerPage());
        feed.setServiceConfig(request.getConfigurator());
        try {
            /*
             * the strategy executes either a search or a direct access.
             */
            BaseFeed retVal = this.storage.getFeed(feed);
            dynamicElementFeedStragey(retVal, request);

            return retVal;
            /*
             * Resource not found will be detected in Gdata request.
             * the request queries the storage for the feed to get the service for the feed
             */
        } catch (StorageException e) {
            ServiceException ex = new ServiceException("Could not get feed", e,GDataResponse.NOT_FOUND);
            ex.setStackTrace(e.getStackTrace());
            throw ex;
        }

    }

    private Link buildLink(String rel, String type, String href) {
        Link retVal = new Link();
        retVal.setHref(href);
        retVal.setRel(rel);
        retVal.setType(type);
        return retVal;
    }

    private ServerBaseEntry buildEntry(final GDataRequest request,
            final GDataResponse response) throws ServiceException {
        try {
            ServerBaseEntry entry = new ServerBaseEntry(GDataEntityBuilder
                    .buildEntry(request));
            return entry;

        } catch (ParseException e) {
            ServiceException ex = new ServiceException(
                    "Could not parse entry from incoming request", e, GDataResponse.BAD_REQUEST);
            ex.setStackTrace(e.getStackTrace());
            throw ex;
        } catch (IOException e) {
            ServiceException ex = new ServiceException(
                    "Could not read or open input stream", e, GDataResponse.BAD_REQUEST);
            ex.setStackTrace(e.getStackTrace());
            throw ex;
        }
    }


    /**
     * @see org.apache.lucene.gdata.server.Service#getSingleEntry(org.apache.lucene.gdata.server.GDataRequest,
     *      org.apache.lucene.gdata.server.GDataResponse)
     */

    public BaseEntry getSingleEntry(GDataRequest request, GDataResponse response)
            throws ServiceException {

        try {
            ServerBaseEntry entry = new ServerBaseEntry();
            entry.setServiceConfig(request.getConfigurator());
            entry.setFeedId(request.getFeedId());
            entry.setId(request.getEntryId());

            
            if(entry.getId() == null){
                throw new ServiceException("entry is null can't get entry", GDataResponse.BAD_REQUEST);
            }
                
            BaseEntry retVal = null;
            retVal = this.storage.getEntry(entry);
            dynamicElementEntryStragey(retVal, request);
            return retVal;
        } catch (ResourceNotFoundException e) {
            ServiceException ex = new ServiceException(
                    "Could not get entry", e, GDataResponse.BAD_REQUEST);
            ex.setStackTrace(e.getStackTrace());
            throw ex;
        } catch (StorageException e) {
            ServiceException ex = new ServiceException("Could not get entry", e, GDataResponse.SERVER_ERROR);
            ex.setStackTrace(e.getStackTrace());
            throw ex;
        }
    }

    /*
     * adds all dynamic element to the entry
     */
    private void dynamicElementEntryStragey(final BaseEntry entry,
            final GDataRequest request) {
        setSelfLink(entry, request.getContextPath());
    }

    /*
     * adds all dynamic element to the feed entries
     */
    @SuppressWarnings("unchecked")
    protected void dynamicElementFeedStragey(final BaseFeed feed,
            final GDataRequest request) {
         buildDynamicFeedElements(request, feed);
        List<BaseEntry> entryList = feed.getEntries();
        for (BaseEntry entry : entryList) {
            String id = new StringBuilder(request.getContextPath()).append(entry.getId()).append("/").toString();
            setSelfLink(entry, id);
        }

    }

    /*
     * The selfLink is build from a prefix and the entry id. The prefix is the
     * context path of the requested feed. This will be used to request the
     * entry directly
     */@SuppressWarnings("unchecked")
    private BaseEntry setSelfLink(final BaseEntry entry, String id) {
        Link self = buildLink(Link.Rel.SELF, XMLMIME, id);
        StringBuilder builder = new StringBuilder(id);
        builder.append(entry.getVersionId());
        Link edit = buildLink(Link.Rel.ENTRY_EDIT,XMLMIME,builder.toString());
        List<Link> list = entry.getLinks();
        list.add(edit);
        list.add(self);
        return entry;
    }

    /*
     * build the dynamic elements like self link and next link
     */
    private void buildDynamicFeedElements(final GDataRequest request,
            final BaseFeed feed) {
        feed.setGenerator(generator);
        feed.setItemsPerPage(request.getItemsPerPage());
        feed.setStartIndex(request.getStartIndex());
        feed.setId(request.getContextPath());
        List<Link> links = feed.getLinks();
        links.add(
                buildLink(Link.Rel.SELF, Link.Type.ATOM, request.getSelfId()));
        links.add(
                buildLink(Link.Rel.NEXT, XMLMIME, request.getNextId()));
        String prevLink = request.getPreviousId();
        if(prevLink != null)
            links.add(buildLink(Link.Rel.PREVIOUS,XMLMIME,prevLink));
        

    }

    /**
     * @see org.apache.lucene.gdata.server.Service#close()
     */
    public void close() {
        this.storage.close();
    }

    /**
     * @see org.apache.lucene.gdata.server.Service#getFeedLastModified(java.lang.String)
     */
    public Date getFeedLastModified(final String feedId) throws ServiceException {
        try {
            return new Date(this.storage.getFeedLastModified(feedId));
           
        } catch (StorageException e) {
            ServiceException ex = new ServiceException(
                    "Could not get Last update for feed -- "+feedId, e, GDataResponse.SERVER_ERROR);
            ex.setStackTrace(e.getStackTrace());
            throw ex;
        }

    }

    /**
     * @see org.apache.lucene.gdata.server.Service#getEntryLastModified(java.lang.String, java.lang.String)
     */
    public Date getEntryLastModified(final String entryId,final String feedId) throws ServiceException {
            try {
                return new Date(this.storage.getEntryLastModified(entryId, feedId));
            } catch (StorageException e) {
                ServiceException ex = new ServiceException(
                        "Could not get Last update for entry  -- "+entryId, e, GDataResponse.SERVER_ERROR);
                ex.setStackTrace(e.getStackTrace());
                throw ex;
            }
        
    }
    private ServerBaseEntry setVersionId(final ServerBaseEntry entry, final GDataRequest request, final GDataResponse response)throws ServiceException{
        try{
            entry.setVersion(Integer.parseInt(request.getEntryVersion()));
            return entry;
        }catch (Exception e) {
            LOG.error("Can not parse entry version -- version is not an integer -- versionid: "+request.getEntryVersion(),e);
            throw new ServiceException("Can not parse entry version -- version is not an integer -- versionid: "+request.getEntryVersion(),e, GDataResponse.BAD_REQUEST);
           
        }
    }
    /*
     * provide current time to set as published / updated values
     * always use servertime to prevent client / server time lag
     * Timezoneshift is 0
     */
    protected DateTime getCurrentDateTime(){
        return new DateTime(System.currentTimeMillis(),0);
    }
    
    private void removeDynamicElements(BaseEntry entry){
        Link selfLink = entry.getSelfLink();
        if(selfLink != null)
            entry.getLinks().remove(selfLink);
        Link editLink = entry.getEditLink();
        if(editLink != null)
            entry.getLinks().remove(editLink);
    }
}