| package myPackage; |
| |
| import java.util.Date; |
| import java.util.List; |
| |
| import javax.activation.MimeType; |
| |
| import org.apache.abdera.Abdera; |
| import org.apache.abdera.factory.StreamBuilder; |
| import org.apache.abdera.i18n.iri.IRI; |
| import org.apache.abdera.model.Document; |
| import org.apache.abdera.model.Entry; |
| import org.apache.abdera.model.Feed; |
| import org.apache.abdera.model.Link; |
| import org.apache.abdera.parser.ParseException; |
| import org.apache.abdera.protocol.server.ProviderHelper; |
| import org.apache.abdera.protocol.server.RequestContext; |
| import org.apache.abdera.protocol.server.ResponseContext; |
| import org.apache.abdera.protocol.server.TargetType; |
| import org.apache.abdera.protocol.server.context.BaseResponseContext; |
| import org.apache.abdera.protocol.server.context.EmptyResponseContext; |
| import org.apache.abdera.protocol.server.context.ResponseContextException; |
| import org.apache.abdera.protocol.server.impl.AbstractCollectionAdapter; |
| import org.apache.abdera.util.MimeTypeHelper; |
| |
| /** |
| * The Collection Adapter is the piece that actually implements the business |
| * logic of the AtomPub server. It bridges the protocol with the backend |
| * persistence. |
| */ |
| public class APP_CollectionAdapter extends AbstractCollectionAdapter { |
| private static String FEED_TAG = "entries"; |
| private Document feedDocument; |
| |
| public ResponseContext getFeed(RequestContext request) { |
| Abdera abdera = request.getAbdera(); |
| Document feed = getFeedDocument(abdera); |
| return new BaseResponseContext(feed); |
| } |
| |
| public ResponseContext postEntry(RequestContext request) { |
| Abdera abdera = request.getAbdera(); |
| try { |
| Document entryDocument = constructEntryDocument(request, abdera); |
| if (entryDocument != null) { |
| Entry entry = (Entry)entryDocument.getRoot(); |
| manageAnEntry(entry, null, abdera); |
| BaseResponseContext rc = new BaseResponseContext(entry); |
| IRI baseUri = ProviderHelper.resolveBase(request); |
| rc.setLocation(baseUri.resolve(FEED_TAG + "/" + entry.getId()).toString()); |
| rc.setStatus(201); //generate a HTTP 201 response in case of success |
| return rc; |
| } else { |
| return new EmptyResponseContext(400); |
| } |
| } catch (ParseException pe) { |
| return new EmptyResponseContext(415); |
| } catch (ClassCastException cce) { |
| return new EmptyResponseContext(415); |
| } catch (Exception e) { |
| return new EmptyResponseContext(400); |
| } |
| } |
| |
| public ResponseContext getEntry(RequestContext request) { |
| Entry entry = (Entry)getAbderaEntry(request); |
| if (entry != null) { |
| Document entryDocument = ((Entry)entry.clone()).getDocument(); |
| return new BaseResponseContext(entryDocument); |
| } else { |
| return new EmptyResponseContext(404); |
| } |
| } |
| |
| public ResponseContext deleteEntry(RequestContext request) { |
| Entry entry = getAbderaEntry(request); |
| if (entry != null) { |
| entry.discard(); |
| return new EmptyResponseContext(204); |
| } else { |
| return new EmptyResponseContext(404); |
| } |
| } |
| |
| public ResponseContext putEntry(RequestContext request) { |
| Entry origEntry = getAbderaEntry(request); |
| if (origEntry != null) { |
| try { |
| Abdera abdera = request.getAbdera(); |
| Document newEntryDocument = constructEntryDocument(request, abdera); |
| if (newEntryDocument != null) { |
| Entry newEntry = (Entry)newEntryDocument.getRoot(); |
| manageAnEntry(newEntry, origEntry, abdera); |
| return new BaseResponseContext(newEntry); |
| } else { |
| return new EmptyResponseContext(400); |
| } |
| } catch (ParseException pe) { |
| return new EmptyResponseContext(415); |
| } catch (ClassCastException cce) { |
| return new EmptyResponseContext(415); |
| } catch (Exception e) { |
| if ("409".equalsIgnoreCase(e.getMessage())) { |
| return new EmptyResponseContext(409); |
| } else { |
| return new EmptyResponseContext(400); |
| } |
| } |
| } else { |
| return new EmptyResponseContext(404); |
| } |
| } |
| |
| private synchronized Document getFeedDocument(Abdera abdera) { |
| if (feedDocument == null) { |
| feedDocument = initializeFeedDocument(abdera); |
| } |
| return feedDocument; |
| } |
| |
| private Document initializeFeedDocument(Abdera abdera) { |
| StreamBuilder out = (StreamBuilder)abdera.getWriterFactory().newStreamWriter("fom"); |
| out.startDocument().startFeed().writeId("http://mile.ee.iisc.ernet.in") |
| .writeTitle("Latest developments at MILE Lab, IISc :") |
| .writeUpdated(new Date()) |
| .writeLink(FEED_TAG) |
| .writeCategory("lab-updates"); |
| |
| out |
| .startEntry() |
| .writeId("tts_demo") |
| .writeTitle("Kannada and Tamil language TTS Web Demo") |
| .writeLink(FEED_TAG + "/tts_demo") |
| .writeUpdated(new Date()) |
| .writePublished(new Date()) |
| .writeEdited(new Date()) |
| .writeSummary("Kannada/Tamil language Text-To-Speech (TTS) Demo by MILE Lab, IISc is " + |
| "available at http://mile.ee.iisc.ernet.in:8080/tts_demo/ ") |
| .writeAuthor("ShivaHR").endEntry(); |
| |
| out |
| .startEntry() |
| .writeId("tamil_ocr") |
| .writeTitle("Tamil OCR achieves 94.3% accuracy on 1000 scanned pages") |
| .writeLink(FEED_TAG + "/tamil_ocr") |
| .writeUpdated(new Date()) |
| .writePublished(new Date()) |
| .writeEdited(new Date()) |
| .writeSummary("Tamil OCR (Optical Character Recognizer) being developed at MILE Lab, IISc " + |
| "achieves an accuracy of 94.3%! The testing was carried out by CDAC-Pune on " + |
| "1000 pages scanned from books printed between 1950-2000.") |
| .writeAuthor("ShivaHR").endEntry(); |
| |
| Document doc = (Document)out.endFeed().endDocument().getBase(); |
| |
| return doc; |
| } |
| |
| /** |
| * Create a skeletal entry, to be filled up later |
| */ |
| private Document constructEntryDocument(RequestContext request, Abdera abdera) throws Exception { |
| MimeType contentType = request.getContentType(); |
| if (contentType != null && !MimeTypeHelper.isAtom(contentType.toString())) { |
| throw new ParseException(); |
| } |
| return (Document)request.getDocument(abdera.getParser()).clone(); |
| } |
| |
| /* |
| * Utility method to manage the creation or update of an entry. |
| */ |
| private void manageAnEntry(Entry currentEntry, Entry originalEntry, Abdera abdera) |
| throws Exception { |
| IRI id; |
| if (originalEntry != null) { |
| id = originalEntry.getId(); |
| if (!currentEntry.getId().equals(id)) { |
| throw new Exception("409"); |
| } |
| originalEntry.discard(); |
| } else { |
| id = currentEntry.getId(); |
| if (id == null) { |
| id = new IRI(abdera.getFactory().newUuidUri()); |
| currentEntry.getIdElement().setValue(id.toString()); |
| } |
| } |
| currentEntry.setUpdated(new Date()); |
| String hrefValue = FEED_TAG + "/" + id; |
| List<Link> links = currentEntry.getLinks(); |
| //links.clear(); //doesn't work - throws a java.lang.UnsupportedOperationException! |
| if (links.size() > 0) { |
| links.get(0).setHref(hrefValue); |
| } else { |
| currentEntry.addLink(hrefValue); |
| } |
| Feed feed = (Feed)getFeedDocument(abdera).getRoot(); |
| feed.insertEntry(currentEntry); |
| feed.setUpdated(new Date()); |
| } |
| |
| private Entry getAbderaEntry(RequestContext request) { |
| Abdera abdera = request.getAbdera(); |
| Document feed = getFeedDocument(abdera); |
| try { |
| Feed currentFeed = (Feed)feed.getRoot(); |
| return currentFeed.getEntry(getEntryID(request)); |
| } catch (Exception e) { |
| e.printStackTrace(); |
| } |
| return null; |
| } |
| |
| /** |
| * The id of the entry is the last token in the URL. Ugly way of extracting |
| * it, till I find a better mechanism. |
| */ |
| private String getEntryID(RequestContext request) { |
| if (request.getTarget().getType() != TargetType.TYPE_ENTRY) { |
| return null; |
| } |
| String path = request.getUri().toString(); |
| String[] segments = path.split("/"); |
| return segments[segments.length - 1]; |
| } |
| |
| public String getAuthor(RequestContext request) throws ResponseContextException { |
| return "ShivaHR"; |
| } |
| |
| public String getId(RequestContext request) { |
| return "blog/entries"; |
| } |
| |
| public String getTitle(RequestContext request) { |
| return "Entries"; |
| } |
| |
| } |
