Java tutorial
/** * Copyright 2009, 2010 The Regents of the University of California * Licensed under the Educational Community License, Version 2.0 * (the "License"); you may not use this file except in compliance * with the License. You may obtain a copy of the License at * * http://www.osedu.org/licenses/ECL-2.0 * * Unless required by applicable law or agreed to in writing, * software distributed under the License is distributed on an "AS IS" * BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express * or implied. See the License for the specific language governing * permissions and limitations under the License. * */ package org.opencastproject.mediapackage.elementbuilder; import java.net.URI; import java.net.URISyntaxException; import java.security.NoSuchAlgorithmException; import javax.xml.xpath.XPathConstants; import javax.xml.xpath.XPathExpressionException; import org.apache.commons.lang.StringUtils; import org.opencastproject.mediapackage.MediaPackageElement; import org.opencastproject.mediapackage.MediaPackageElement.Type; import org.opencastproject.mediapackage.MediaPackageElementFlavor; import org.opencastproject.mediapackage.MediaPackageReferenceImpl; import org.opencastproject.mediapackage.MediaPackageSerializer; import org.opencastproject.mediapackage.Publication; import org.opencastproject.mediapackage.PublicationImpl; import org.opencastproject.mediapackage.UnsupportedElementException; import org.opencastproject.util.Checksum; import org.opencastproject.util.MimeType; import org.opencastproject.util.MimeTypes; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.w3c.dom.Node; import org.w3c.dom.NodeList; public class PublicationBuilderPlugin extends AbstractElementBuilderPlugin { /** * the logging facility provided by log4j */ private static final Logger logger = LoggerFactory.getLogger(PublicationBuilderPlugin.class); @Override public boolean accept(Type type, MediaPackageElementFlavor flavor) { return type.equals(MediaPackageElement.Type.Publication); } @Override public boolean accept(URI uri, Type type, MediaPackageElementFlavor flavor) { return MediaPackageElement.Type.Publication.equals(type); } @Override public boolean accept(Node elementNode) { String name = elementNode.getNodeName(); if (name.contains(":")) { name = name.substring(name.indexOf(":") + 1); } return name.equalsIgnoreCase(MediaPackageElement.Type.Publication.toString()); } @Override public MediaPackageElement elementFromURI(URI uri) throws UnsupportedElementException { // TODO Auto-generated method stub logger.trace("Creating publication element from " + uri); Publication publication = new PublicationImpl(); publication.setURI(uri); return publication; } @Override public MediaPackageElement elementFromManifest(Node elementNode, MediaPackageSerializer serializer) throws UnsupportedElementException { String id = null; MimeType mimeType = null; MediaPackageElementFlavor flavor = null; String reference = null; String channel = null; URI url = null; long size = -1; Checksum checksum = null; try { // id id = (String) xpath.evaluate("@id", elementNode, XPathConstants.STRING); if (StringUtils.isEmpty(id)) { throw new UnsupportedElementException("Unvalid or missing id argument!"); } // url url = serializer.resolvePath(xpath.evaluate("url/text()", elementNode).trim()); // channel channel = (String) xpath.evaluate("@channel", elementNode).trim(); if (StringUtils.isEmpty(channel)) { throw new UnsupportedElementException("Unvalid or missing channel argument!"); } // reference reference = (String) xpath.evaluate("@ref", elementNode, XPathConstants.STRING); // size String trackSize = xpath.evaluate("size/text()", elementNode).trim(); if (!"".equals(trackSize)) size = Long.parseLong(trackSize); // flavor String flavorValue = (String) xpath.evaluate("@type", elementNode, XPathConstants.STRING); if (StringUtils.isNotEmpty(flavorValue)) flavor = MediaPackageElementFlavor.parseFlavor(flavorValue); // checksum String checksumValue = (String) xpath.evaluate("checksum/text()", elementNode, XPathConstants.STRING); String checksumType = (String) xpath.evaluate("checksum/@type", elementNode, XPathConstants.STRING); if (StringUtils.isNotEmpty(checksumValue) && checksumType != null) checksum = Checksum.create(checksumType.trim(), checksumValue.trim()); // mimetype String mimeTypeValue = (String) xpath.evaluate("mimetype/text()", elementNode, XPathConstants.STRING); if (StringUtils.isNotEmpty(mimeTypeValue)) { mimeType = MimeTypes.parseMimeType(mimeTypeValue); } else { throw new UnsupportedElementException("Unvalid or missing mimetype argument!"); } // Build the publication element PublicationImpl publication = new PublicationImpl(id, channel, url, mimeType); if (StringUtils.isNotBlank(id)) publication.setIdentifier(id); // Add url publication.setURI(url); // Add reference if (StringUtils.isNotEmpty(reference)) publication.referTo(MediaPackageReferenceImpl.fromString(reference)); // Set size if (size > 0) publication.setSize(size); // Set checksum if (checksum != null) publication.setChecksum(checksum); // Set mimetpye if (mimeType != null) publication.setMimeType(mimeType); if (flavor != null) publication.setFlavor(flavor); // description String description = (String) xpath.evaluate("description/text()", elementNode, XPathConstants.STRING); if (StringUtils.isNotBlank(description)) publication.setElementDescription(description.trim()); // tags NodeList tagNodes = (NodeList) xpath.evaluate("tags/tag", elementNode, XPathConstants.NODESET); for (int i = 0; i < tagNodes.getLength(); i++) { publication.addTag(tagNodes.item(i).getTextContent()); } return publication; } catch (XPathExpressionException e) { throw new UnsupportedElementException( "Error while reading track information from manifest: " + e.getMessage()); } catch (NoSuchAlgorithmException e) { throw new UnsupportedElementException("Unsupported digest algorithm: " + e.getMessage()); } catch (URISyntaxException e) { throw new UnsupportedElementException( "Error while reading presenter track " + url + ": " + e.getMessage()); } } @Override public MediaPackageElement newElement(Type type, MediaPackageElementFlavor flavor) { Publication element = new PublicationImpl(); element.setFlavor(flavor); return element; } }