Java tutorial
/** * The contents of this file are subject to the license and copyright * detailed in the LICENSE and NOTICE files at the root of the source * tree and available online at * * http://www.dspace.org/license/ */ package org.dspace.app.sfx; import java.io.File; import java.io.IOException; import java.net.URLEncoder; import org.apache.commons.lang.StringUtils; import org.apache.log4j.Logger; import org.w3c.dom.Document; import org.dspace.content.DCPersonName; import org.dspace.content.DCValue; import org.dspace.content.Item; import org.dspace.core.Constants; import javax.xml.parsers.DocumentBuilderFactory; import javax.xml.parsers.DocumentBuilder; import javax.xml.parsers.ParserConfigurationException; import org.w3c.dom.NamedNodeMap; import org.w3c.dom.Node; import org.w3c.dom.NodeList; import org.xml.sax.SAXException; /** * XML configuration file reader for DSpace metadata fields (DC) mapping * to OpenURL parameters. * <p> * This class reads the [dspace]/config/sfx.xml configuration file, which * contains pairs of DSpace item metadata values and OpenURL parameter names. * Then it takes an item and constructs an OpenURL for it with values of * parameters filled in from the paired metadata fields. * </p> * * @author Stuart Lewis * @author Graham Triggs * @version $Revision$ */ public class SFXFileReader { /** The SFX configuration file */ private static Document doc; /** log4j logger */ private static final Logger log = Logger.getLogger(SFXFileReader.class); /** * Loads the SFX configuraiton file * * @param fileName The name of the SFX configuration file * @param item The item to process, from which metadata values will be taken * * @return the SFX string * @throws IOException */ public static String loadSFXFile(String fileName, Item item) throws IOException { // Parse XML file -> XML document will be build if (doc == null) { doc = parseFile(fileName); } // Return final sfx Query String return doNodes(doc, item); } /** Parses XML file and returns XML document. * @param fileName XML file to parse * @return XML document or <B>null</B> if error occured. The error is caught and logged. */ public static Document parseFile(String fileName) { log.info("Parsing XML file... " + fileName); DocumentBuilder docBuilder; Document doc = null; DocumentBuilderFactory docBuilderFactory = DocumentBuilderFactory.newInstance(); docBuilderFactory.setIgnoringElementContentWhitespace(true); try { docBuilder = docBuilderFactory.newDocumentBuilder(); } catch (ParserConfigurationException e) { log.error("Wrong parser configuration: " + e.getMessage()); return null; } File sourceFile = new File(fileName); try { doc = docBuilder.parse(sourceFile); } catch (SAXException e) { log.error("Wrong XML file structure: " + e.getMessage()); return null; } catch (IOException e) { log.error("Could not read source file: " + e.getMessage()); } log.info("XML file parsed"); return doc; } /** * Process the item, mapping each of its metadata fields defined in the * configuration file to an OpenURL parameter * * @param node DOM node of the mapping pair in the XML file (field element) * @param item The item to process, from which metadata values will be taken * @return processed fields. * @throws IOException */ public static String doNodes(Node node, Item item) throws IOException { if (node == null) { log.error(" Empty Node "); return null; } Node e = getElement(node); NodeList nl = e.getChildNodes(); int len = nl.getLength(); String sfxfield = ""; int i = 0; while ((i < len) && StringUtils.isEmpty(sfxfield)) { Node nd = nl.item(i); if ((nd == null) || isEmptyTextNode(nd)) { i++; continue; } String tagName = nd.getNodeName(); if (tagName.equals("query-pairs")) { sfxfield = processFields(nd, item); } i++; } log.info("Process fields : " + sfxfield); return sfxfield; } /** * Process the field nodes, mapping each metadata field defined in the * configuration file to an OpenURL parameter * * @param e DOM node of the mapping pair in the XML file (field element) * @param item The item to process, from which metadata values will be taken * @return assembled OpenURL query. * @throws IOException */ private static String processFields(Node e, Item item) throws IOException { NodeList cl = e.getChildNodes(); int lench = cl.getLength(); String myquery = ""; for (int j = 0; j < lench; j++) { Node nch = cl.item(j); String querystring = ""; String schema = ""; String qualifier = ""; String element = ""; if (nch.getNodeName().equals("field")) { NodeList pl = nch.getChildNodes(); int plen = pl.getLength(); int finish = 0; for (int k = 0; k < plen; k++) { Node vn = pl.item(k); String vName = vn.getNodeName(); if (vName.equals("querystring")) { querystring = getValue(vn); finish++; } else if (vName.equals("dc-schema")) { schema = getValue(vn); finish++; } else if (vName.equals("dc-element")) { element = getValue(vn); finish++; } else if (vName.equals("dc-qualifier")) { qualifier = getValue(vn); finish++; if (StringUtils.isEmpty(qualifier)) { qualifier = null; } } if (finish == 4) { DCValue[] dcvalue = item.getMetadata(schema, element, qualifier, Item.ANY); if (dcvalue.length > 0) { // Issued Date if (element.equals("date") && qualifier.equals("issued")) { String fullDate = dcvalue[0].value; // Remove the time if there is one - day is greatest granularity for SFX if (fullDate.length() > 10) { fullDate = fullDate.substring(0, 10); } if (myquery.equals("")) { myquery = querystring + URLEncoder.encode(fullDate, Constants.DEFAULT_ENCODING); } else { myquery = myquery + "&" + querystring + URLEncoder.encode(fullDate, Constants.DEFAULT_ENCODING); } } else { // Contributor Author if (element.equals("contributor") && qualifier.equals("author")) { DCPersonName dpn = new DCPersonName(dcvalue[0].value); String dpnName = dcvalue[0].value; if (querystring.endsWith("aulast=")) { dpnName = dpn.getLastName(); } else { if (querystring.endsWith("aufirst=")) { dpnName = dpn.getFirstNames(); } } if (myquery.equals("")) { myquery = querystring + URLEncoder.encode(dpnName, Constants.DEFAULT_ENCODING); } else { myquery = myquery + "&" + querystring + URLEncoder.encode(dpnName, Constants.DEFAULT_ENCODING); } } else { if (myquery.equals("")) { myquery = querystring + URLEncoder.encode(dcvalue[0].value, Constants.DEFAULT_ENCODING); } else { myquery = myquery + "&" + querystring + URLEncoder.encode(dcvalue[0].value, Constants.DEFAULT_ENCODING); } } } } // if dc.length > 0 finish = 0; querystring = ""; schema = ""; element = ""; qualifier = ""; } // if finish == 4 } //for k } // if field } // for j return myquery; } /** Returns element node * @param node element (it is XML tag) * @return Element node otherwise null */ public static Node getElement(Node node) { NodeList child = node.getChildNodes(); int length = child.getLength(); for (int i = 0; i < length; i++) { Node kid = child.item(i); if (kid.getNodeType() == Node.ELEMENT_NODE) { return kid; } } return null; } /** Is Empty text Node **/ public static boolean isEmptyTextNode(Node nd) { boolean isEmpty = false; if (nd.getNodeType() == Node.TEXT_NODE) { String text = nd.getNodeValue().trim(); if (text.length() == 0) { isEmpty = true; } } return isEmpty; } /** * Returns the value of the node's attribute named <name> **/ public static String getAttribute(Node e, String name) { NamedNodeMap attrs = e.getAttributes(); int len = attrs.getLength(); if (len > 0) { for (int i = 0; i < len; i++) { Node attr = attrs.item(i); if (name.equals(attr.getNodeName())) { return attr.getNodeValue().trim(); } } } //no such attribute return null; } /** * Returns the value found in the Text node (if any) in the * node list that's passed in. */ public static String getValue(Node node) { NodeList child = node.getChildNodes(); for (int i = 0; i < child.getLength(); i++) { Node kid = child.item(i); short type = kid.getNodeType(); if (type == Node.TEXT_NODE) { return kid.getNodeValue().trim(); } } // Didn't find a text node return null; } }