Java tutorial
/* ************************************************************************ ******************* CANADIAN ASTRONOMY DATA CENTRE ******************* ************** CENTRE CANADIEN DE DONNES ASTRONOMIQUES ************** * * (c) 2009. (c) 2009. * Government of Canada Gouvernement du Canada * National Research Council Conseil national de recherches * Ottawa, Canada, K1A 0R6 Ottawa, Canada, K1A 0R6 * All rights reserved Tous droits rservs * * NRC disclaims any warranties, Le CNRC dnie toute garantie * expressed, implied, or nonce, implicite ou lgale, * statutory, of any kind with de quelque nature que ce * respect to the software, soit, concernant le logiciel, * including without limitation y compris sans restriction * any warranty of merchantability toute garantie de valeur * or fitness for a particular marchande ou de pertinence * purpose. NRC shall not be pour un usage particulier. * liable in any event for any Le CNRC ne pourra en aucun cas * damages, whether direct or tre tenu responsable de tout * indirect, special or general, dommage, direct ou indirect, * consequential or incidental, particulier ou gnral, * arising from the use of the accessoire ou fortuit, rsultant * software. Neither the name de l'utilisation du logiciel. Ni * of the National Research le nom du Conseil National de * Council of Canada nor the Recherches du Canada ni les noms * names of its contributors may de ses participants ne peuvent * be used to endorse or promote tre utiliss pour approuver ou * products derived from this promouvoir les produits drivs * software without specific prior de ce logiciel sans autorisation * written permission. pralable et particulire * par crit. * * This file is part of the Ce fichier fait partie du projet * OpenCADC project. OpenCADC. * * OpenCADC is free software: OpenCADC est un logiciel libre ; * you can redistribute it and/or vous pouvez le redistribuer ou le * modify it under the terms of modifier suivant les termes de * the GNU Affero General Public la GNU Affero General Public * License as published by the License? telle que publie * Free Software Foundation, par la Free Software Foundation * either version 3 of the : soit la version 3 de cette * License, or (at your option) licence, soit ( votre gr) * any later version. toute version ultrieure. * * OpenCADC is distributed in the OpenCADC est distribu * hope that it will be useful, dans lespoir quil vous * but WITHOUT ANY WARRANTY; sera utile, mais SANS AUCUNE * without even the implied GARANTIE : sans mme la garantie * warranty of MERCHANTABILITY implicite de COMMERCIALISABILIT * or FITNESS FOR A PARTICULAR ni dADQUATION UN OBJECTIF * PURPOSE. See the GNU Affero PARTICULIER. Consultez la Licence * General Public License for Gnrale Publique GNU Affero * more details. pour plus de dtails. * * You should have received Vous devriez avoir reu une * a copy of the GNU Affero copie de la Licence Gnrale * General Public License along Publique GNU Affero avec * with OpenCADC. If not, see OpenCADC ; si ce nest * <http://www.gnu.org/licenses/>. pas le cas, consultez : * <http://www.gnu.org/licenses/>. * * $Revision: 4 $ * ************************************************************************ */ package ca.nrc.cadc.vos.server; import java.util.Collection; import org.apache.log4j.Logger; import org.jdom2.Element; import ca.nrc.cadc.util.StringUtil; import ca.nrc.cadc.vos.DataNode; import ca.nrc.cadc.vos.Node; import ca.nrc.cadc.vos.NodeProperty; import ca.nrc.cadc.vos.VOS; /** * * @author jburke */ public class RssFeed { private static Logger log = Logger.getLogger(RssFeed.class); /** * Builds a JDOM Element representing the RRS feed of set of Nodes. * * @param parent The parent Node of all other Nodes in the feed. * @param nodes Collection of nodes to display in the feed. * @param baseURL base url for the nodes resource * @return JDOM Element representing the RRS feed. */ public static Element createFeed(Node parent, Collection<RssFeedItem> nodes, String baseURL) { // Get the title and description from the parent properties. String parentTitle = null; String parentDescription = null; for (NodeProperty nodeProperty : parent.getProperties()) { if (nodeProperty.getPropertyURI().equals(VOS.PROPERTY_URI_TITLE)) { parentTitle = nodeProperty.getPropertyValue(); } if (nodeProperty.getPropertyURI().equals(VOS.PROPERTY_URI_DESCRIPTION)) { parentDescription = nodeProperty.getPropertyValue(); } } // Root element. Element rss = new Element("rss"); rss.setAttribute("version", "2.0"); // channel element. Element channel = new Element("channel"); rss.addContent(channel); // channel title. if (parentTitle == null) { parentTitle = "Last modified nodes for " + parent.getName(); } Element channelTitle = new Element("title"); channelTitle.setText(parentTitle); channel.addContent(channelTitle); // channel description. if (parentDescription == null) { parentDescription = nodes.size() + " last modified nodes"; } Element channelDescription = new Element("description"); channelDescription.setText(parentDescription); channel.addContent(channelDescription); // channel link. Element link = new Element("link"); link.setText(baseURL + parent.getUri().getPath() + "?view=rss"); channel.addContent(link); // channel author NodeProperty creator = parent.findProperty(VOS.PROPERTY_URI_CREATOR); if (creator != null && StringUtil.hasText(creator.getPropertyValue())) { Element author = new Element("author"); author.setText(creator.getPropertyValue()); channel.addContent(author); } log.debug("num nodes: " + nodes.size()); // Create an item for each Node and add to channel. for (RssFeedItem rssFeedItem : nodes) { // Get the title, description, and date from the node properties. String nodeTitle = null; String nodeDescription = null; String nodeDate = null; for (NodeProperty nodeProperty : rssFeedItem.node.getProperties()) { if (nodeProperty.getPropertyURI().equals(VOS.PROPERTY_URI_TITLE)) { nodeTitle = nodeProperty.getPropertyValue(); } if (nodeProperty.getPropertyURI().equals(VOS.PROPERTY_URI_DESCRIPTION)) { nodeDescription = nodeProperty.getPropertyValue(); } if (nodeProperty.getPropertyURI().equals(VOS.PROPERTY_URI_DATE)) { nodeDate = nodeProperty.getPropertyValue(); } } // item element. Element item = new Element("item"); // item title. if (nodeTitle == null) { nodeTitle = rssFeedItem.node.getName(); } Element itemTitle = new Element("title"); itemTitle.setText(nodeTitle); item.addContent(itemTitle); // item description. if (nodeDescription == null) { if (rssFeedItem.node instanceof DataNode) { nodeDescription = "File"; } else { nodeDescription = "Directory"; } } Element itemDescription = new Element("description"); itemDescription.setText(nodeDescription); item.addContent(itemDescription); // item pubDate if (nodeDate != null) { Element itemPubDate = new Element("pubDate"); itemPubDate.setText(nodeDate); item.addContent(itemPubDate); } // item link, comment Element itemLink = new Element("link"); Element comments = new Element("comments"); String linkText = baseURL + rssFeedItem.node.getUri().getPath(); if (rssFeedItem.node instanceof DataNode) { linkText += "?view=data"; comments.setText("Click to download this file."); } else { linkText += "?view=rss"; comments.setText("Click to see the last modified nodes within this directory."); } itemLink.setText(linkText); item.addContent(itemLink); item.addContent(comments); // item author creator = rssFeedItem.node.findProperty(VOS.PROPERTY_URI_CREATOR); if (creator != null && StringUtil.hasText(creator.getPropertyValue())) { Element author = new Element("author"); author.setText(creator.getPropertyValue()); item.addContent(author); } // Add item to channel channel.addContent(item); } return rss; } /** * Builds a JDOM Element representing a RRS feed that displays an error state. * * @param node The Node causing the error. * @param throwable The Throwable containing the message to display. * @param baseURL base url for the nodes resource * @return JDOM Element representing the RRS feed. */ public static Element createErrorFeed(Node node, Throwable throwable, String baseURL) { return createErrorFeed(node, throwable.getMessage(), baseURL); } /** * Builds a JDOM Element representing a RRS feed that displays an error state. * * @param node The Node causing the error. * @param message The message to display. * @param baseURL base url for the nodes resource * @return JDOM Element representing the RRS feed. */ public static Element createErrorFeed(Node node, String message, String baseURL) { // Root element. Element rss = new Element("rss"); rss.setAttribute("version", "2.0"); // channel element. Element channel = new Element("channel"); rss.addContent(channel); // channel title. Element title = new Element("title"); String nodeName = node.getName(); if (nodeName == null) { nodeName = "unknown node"; } title.setText("Error processing Node " + nodeName); channel.addContent(title); // channel link. Element link = new Element("link"); String nodePath = node.getUri().getPath(); if (nodePath == null) { link.setText("unknown link"); } else { link.setText(baseURL + nodePath + "?view=rss"); } channel.addContent(link); // channel description. Element description = new Element("description"); description.setText(message); channel.addContent(description); return rss; } }