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.content.crosswalk; import java.io.File; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.IOException; import java.io.OutputStream; import java.sql.SQLException; import java.util.ArrayList; import java.util.Enumeration; import java.util.List; import org.apache.commons.lang.ArrayUtils; import org.apache.log4j.Logger; import org.dspace.authorize.AuthorizeException; import org.dspace.content.DCValue; import org.dspace.content.DSpaceObject; import org.dspace.content.Collection; import org.dspace.content.Community; import org.dspace.content.Item; import org.dspace.content.Site; import org.dspace.content.authority.Choices; import org.dspace.core.ConfigurationManager; import org.dspace.core.Constants; import org.dspace.core.Context; import org.dspace.core.PluginManager; import org.dspace.handle.HandleManager; import org.jdom.Document; import org.jdom.Element; import org.jdom.Namespace; import org.jdom.Verifier; import org.jdom.output.Format; import org.jdom.output.XMLOutputter; import org.jdom.transform.XSLTransformException; import org.jdom.transform.XSLTransformer; /** * Configurable XSLT-driven dissemination Crosswalk * <p> * See the XSLTCrosswalk superclass for details on configuration. * <p> * <h3>Additional Configuration of Dissemination crosswalk:</h3> * The disseminator also needs to be configured with an XML Namespace * (including prefix and URI) and an XML Schema for output format. This * is configured on additional properties in the DSpace Configuration, i.e.: * <pre> * crosswalk.dissemination.<i>PluginName</i>.namespace.<i>Prefix</i> = <i>namespace-URI</i> * crosswalk.dissemination.<i>PluginName</i>.schemaLocation = <i>schemaLocation value</i> * crosswalk.dissemination.<i>PluginName</i>.preferList = <i>boolean</i> (default is false) * </pre> * For example: * <pre> * crosswalk.dissemination.qdc.namespace.dc = http://purl.org/dc/elements/1.1/ * crosswalk.dissemination.qdc.namespace.dcterms = http://purl.org/dc/terms/ * crosswalk.dissemination.qdc.schemaLocation = \ * http://purl.org/dc/elements/1.1/ http://dublincore.org/schemas/xmls/qdc/2003/04/02/qualifieddc.xsd * crosswalk.dissemination.qdc.preferList = true * </pre> * * @author Larry Stone * @author Scott Phillips * @author Pascal-Nicolas Becker * @version $Revision$ * @see XSLTCrosswalk */ public class XSLTDisseminationCrosswalk extends XSLTCrosswalk implements DisseminationCrosswalk { /** log4j category */ private static Logger log = Logger.getLogger(XSLTDisseminationCrosswalk.class); /** DSpace context, will be created if XSLTDisseminationCrosswalk had been started by command-line. */ private static Context context; private static final String DIRECTION = "dissemination"; private static String aliases[] = makeAliases(DIRECTION); public static String[] getPluginNames() { return (String[]) ArrayUtils.clone(aliases); } // namespace and schema; don't worry about initializing these // until there's an instance, so do it in constructor. private String schemaLocation = null; private Namespace namespaces[] = null; private boolean preferList = false; // load the namespace and schema from config private void init() throws CrosswalkInternalException { if (namespaces != null || schemaLocation != null) { return; } String myAlias = getPluginInstanceName(); if (myAlias == null) { log.error( "Must use PluginManager to instantiate XSLTDisseminationCrosswalk so the class knows its name."); throw new CrosswalkInternalException( "Must use PluginManager to instantiate XSLTDisseminationCrosswalk so the class knows its name."); } // all configs for this plugin instance start with this: String prefix = CONFIG_PREFIX + DIRECTION + "." + myAlias + "."; // get the schema location string, should already be in the // right format for value of "schemaLocation" attribute. schemaLocation = ConfigurationManager.getProperty(prefix + "schemaLocation"); if (schemaLocation == null) { log.warn("No schemaLocation for crosswalk=" + myAlias + ", key=" + prefix + "schemaLocation"); } // sanity check: schemaLocation should have space. else if (schemaLocation.length() > 0 && schemaLocation.indexOf(' ') < 0) { log.warn("Possible INVALID schemaLocation (no space found) for crosswalk=" + myAlias + ", key=" + prefix + "schemaLocation" + "\n\tCorrect format is \"{namespace} {schema-URL}\""); } // grovel for namespaces of the form: // crosswalk.diss.{PLUGIN_NAME}.namespace.{PREFIX} = {URI} String nsPrefix = prefix + "namespace."; Enumeration<String> pe = (Enumeration<String>) ConfigurationManager.propertyNames(); List<Namespace> nsList = new ArrayList<Namespace>(); while (pe.hasMoreElements()) { String key = pe.nextElement(); if (key.startsWith(nsPrefix)) { nsList.add(Namespace.getNamespace(key.substring(nsPrefix.length()), ConfigurationManager.getProperty(key))); } } namespaces = nsList.toArray(new Namespace[nsList.size()]); preferList = ConfigurationManager.getBooleanProperty(prefix + "preferList", false); } /** * Return the namespace used by this crosswalk. * * @see DisseminationCrosswalk */ public Namespace[] getNamespaces() { try { init(); } catch (CrosswalkInternalException e) { log.error(e.toString()); } return (Namespace[]) ArrayUtils.clone(namespaces); } /** * Return the schema location used by this crosswalk. * * @see DisseminationCrosswalk */ public String getSchemaLocation() { try { init(); } catch (CrosswalkInternalException e) { log.error(e.toString()); } return schemaLocation; } /** * Disseminate the DSpace item, collection, or community. * * @see DisseminationCrosswalk */ public Element disseminateElement(DSpaceObject dso) throws CrosswalkException, IOException, SQLException, AuthorizeException { int type = dso.getType(); if (!(type == Constants.ITEM || type == Constants.COLLECTION || type == Constants.COMMUNITY)) { throw new CrosswalkObjectNotSupported( "XSLTDisseminationCrosswalk can only crosswalk items, collections, and communities."); } init(); XSLTransformer xform = getTransformer(DIRECTION); if (xform == null) { throw new CrosswalkInternalException( "Failed to initialize transformer, probably error loading stylesheet."); } try { Document ddim = new Document(createDIM(dso)); Document result = xform.transform(ddim); Element root = result.getRootElement(); root.detach(); return root; } catch (XSLTransformException e) { log.error("Got error: " + e.toString()); throw new CrosswalkInternalException("XSL translation failed: " + e.toString(), e); } } /** * Disseminate the DSpace item, collection, or community. * * @see DisseminationCrosswalk */ public List<Element> disseminateList(DSpaceObject dso) throws CrosswalkException, IOException, SQLException, AuthorizeException { int type = dso.getType(); if (!(type == Constants.ITEM || type == Constants.COLLECTION || type == Constants.COMMUNITY)) { throw new CrosswalkObjectNotSupported( "XSLTDisseminationCrosswalk can only crosswalk a items, collections, and communities."); } init(); XSLTransformer xform = getTransformer(DIRECTION); if (xform == null) { throw new CrosswalkInternalException( "Failed to initialize transformer, probably error loading stylesheet."); } try { return xform.transform(createDIM(dso).getChildren()); } catch (XSLTransformException e) { log.error("Got error: " + e.toString()); throw new CrosswalkInternalException("XSL translation failed: " + e.toString(), e); } } /** * Determine is this crosswalk can dessiminate the given object. * * @see DisseminationCrosswalk */ public boolean canDisseminate(DSpaceObject dso) { return dso.getType() == Constants.ITEM; } /** * return true if this crosswalk prefers the list form over an single * element, otherwise false. * * @see DisseminationCrosswalk */ public boolean preferList() { try { init(); } catch (CrosswalkInternalException e) { log.error(e.toString()); } return preferList; } /** * Generate an intermediate representation of a DSpace object. * * @param dso The dspace object to build a representation of. */ public static Element createDIM(DSpaceObject dso, DCValue[] dcvs) { Element dim = new Element("dim", DIM_NS); String type = Constants.typeText[dso.getType()]; dim.setAttribute("dspaceType", type); for (int i = 0; i < dcvs.length; i++) { DCValue dcv = dcvs[i]; Element field = createField(dcv.schema, dcv.element, dcv.qualifier, dcv.language, dcv.value, dcv.authority, dcv.confidence); dim.addContent(field); } return dim; } /** * Generate an intermediate representation of a DSpace object. * * @param dso The dspace object to build a representation of. */ public static Element createDIM(DSpaceObject dso) { if (dso.getType() == Constants.ITEM) { Item item = (Item) dso; return createDIM(dso, item.getMetadata(Item.ANY, Item.ANY, Item.ANY, Item.ANY)); } else { Element dim = new Element("dim", DIM_NS); String type = Constants.typeText[dso.getType()]; dim.setAttribute("dspaceType", type); if (dso.getType() == Constants.COLLECTION) { Collection collection = (Collection) dso; String description = collection.getMetadata("introductory_text"); String description_abstract = collection.getMetadata("short_description"); String description_table = collection.getMetadata("side_bar_text"); String identifier_uri = "hdl:" + collection.getHandle(); String provenance = collection.getMetadata("provenance_description"); String rights = collection.getMetadata("copyright_text"); String rights_license = collection.getMetadata("license"); String title = collection.getMetadata("name"); dim.addContent(createField("dc", "description", null, null, description)); dim.addContent(createField("dc", "description", "abstract", null, description_abstract)); dim.addContent(createField("dc", "description", "tableofcontents", null, description_table)); dim.addContent(createField("dc", "identifier", "uri", null, identifier_uri)); dim.addContent(createField("dc", "provenance", null, null, provenance)); dim.addContent(createField("dc", "rights", null, null, rights)); dim.addContent(createField("dc", "rights", "license", null, rights_license)); dim.addContent(createField("dc", "title", null, null, title)); } else if (dso.getType() == Constants.COMMUNITY) { Community community = (Community) dso; String description = community.getMetadata("introductory_text"); String description_abstract = community.getMetadata("short_description"); String description_table = community.getMetadata("side_bar_text"); String identifier_uri = "hdl:" + community.getHandle(); String rights = community.getMetadata("copyright_text"); String title = community.getMetadata("name"); dim.addContent(createField("dc", "description", null, null, description)); dim.addContent(createField("dc", "description", "abstract", null, description_abstract)); dim.addContent(createField("dc", "description", "tableofcontents", null, description_table)); dim.addContent(createField("dc", "identifier", "uri", null, identifier_uri)); dim.addContent(createField("dc", "rights", null, null, rights)); dim.addContent(createField("dc", "title", null, null, title)); } else if (dso.getType() == Constants.SITE) { Site site = (Site) dso; String identifier_uri = "hdl:" + site.getHandle(); String title = site.getName(); String url = site.getURL(); //FIXME: adding two URIs for now (site handle and URL), in case site isn't using handles dim.addContent(createField("dc", "identifier", "uri", null, identifier_uri)); dim.addContent(createField("dc", "identifier", "uri", null, url)); dim.addContent(createField("dc", "title", null, null, title)); } // XXX FIXME: Nothing to crosswalk for bitstream? return dim; } } /** * Create a new DIM field element with the given attributes. * * @param schema The schema the DIM field belongs to. * @param element The element the DIM field belongs to. * @param qualifier The qualifier the DIM field belongs to. * @param language The language the DIM field belongs to. * @param value The value of the DIM field. * @return A new DIM field element */ private static Element createField(String schema, String element, String qualifier, String language, String value) { return createField(schema, element, qualifier, language, value, null, -1); } /** * Create a new DIM field element with the given attributes. * * @param schema The schema the DIM field belongs to. * @param element The element the DIM field belongs to. * @param qualifier The qualifier the DIM field belongs to. * @param language The language the DIM field belongs to. * @param value The value of the DIM field. * @param authority The authority * @param confidence confidence in the authority * @return A new DIM field element */ private static Element createField(String schema, String element, String qualifier, String language, String value, String authority, int confidence) { Element field = new Element("field", DIM_NS); field.setAttribute("mdschema", schema); field.setAttribute("element", element); if (qualifier != null) { field.setAttribute("qualifier", qualifier); } if (language != null) { field.setAttribute("lang", language); } field.setText(checkedString(value)); if (authority != null) { field.setAttribute("authority", authority); field.setAttribute("confidence", Choices.getConfidenceText(confidence)); } return field; } // Return string with non-XML characters (i.e. low control chars) excised. private static String checkedString(String value) { if (value == null) { return null; } String reason = Verifier.checkCharacterData(value); if (reason == null) { return value; } else { if (log.isDebugEnabled()) { log.debug("Filtering out non-XML characters in string, reason=" + reason); } StringBuffer result = new StringBuffer(value.length()); for (int i = 0; i < value.length(); ++i) { char c = value.charAt(i); if (Verifier.isXMLCharacter((int) c)) { result.append(c); } } return result.toString(); } } /** * Simple command-line rig for testing the DIM output of a stylesheet. * Usage: java XSLTDisseminationCrosswalk <crosswalk-name> <handle> [output-file] */ public static void main(String[] argv) throws Exception { log.error("started."); if (argv.length < 2 || argv.length > 3) { System.err.println("Usage: java XSLTDisseminationCrosswalk <crosswalk-name> <handle> [output-file]"); log.error("You started Dissemination Crosswalk Test/Export with a wrong number of parameters."); System.exit(1); } String xwalkname = argv[0]; String handle = argv[1]; OutputStream out = System.out; if (argv.length > 2) { try { out = new FileOutputStream(argv[2]); } catch (FileNotFoundException e) { System.err.println("Can't write to the specified file: " + e.getMessage()); System.err.println("Will write output to stdout."); } } DisseminationCrosswalk xwalk = (DisseminationCrosswalk) PluginManager .getNamedPlugin(DisseminationCrosswalk.class, xwalkname); if (xwalk == null) { System.err.println("Error: Cannot find a DisseminationCrosswalk plugin for: \"" + xwalkname + "\""); log.error("Cannot find the Dissemination Crosswalk plugin."); System.exit(1); } context = new Context(); context.turnOffAuthorisationSystem(); DSpaceObject dso = null; try { dso = HandleManager.resolveToObject(context, handle); } catch (SQLException e) { System.err.println( "Error: A problem with the database connection occurred, check logs for further information."); System.exit(1); } if (null == dso) { System.err.println("Can't find a DSpaceObject with the handle \"" + handle + "\""); System.exit(1); } if (!xwalk.canDisseminate(dso)) { System.err.println("Dissemination Crosswalk can't disseminate this DSpaceObject."); log.error("Dissemination Crosswalk can't disseminate this DSpaceObject."); System.exit(1); } Element root = null; try { root = xwalk.disseminateElement(dso); } catch (Exception e) { // as this script is for testing dissemination crosswalks, we want // verbose information in case of an exception. System.err.println("An error occurred while processing the dissemination crosswalk."); System.err.println("=== Error Message ==="); System.err.println(e.getMessage()); System.err.println("=== Stack Trace ==="); e.printStackTrace(); System.err.println("====================="); log.error("Caught: " + e.toString() + "."); log.error(e.getMessage()); log.error(e.getStackTrace()); System.exit(1); } try { XMLOutputter xmlout = new XMLOutputter(Format.getPrettyFormat()); xmlout.output(new Document(root), out); } catch (Exception e) { // as this script is for testing dissemination crosswalks, we want // verbose information in case of an exception. System.err.println("An error occurred after processing the dissemination crosswalk."); System.err.println("The error occurred while trying to print the generated XML."); System.err.println("=== Error Message ==="); System.err.println(e.getMessage()); System.err.println("=== Stack Trace ==="); System.err.println(e.getStackTrace()); System.err.println("====================="); log.error("Caught: " + e.toString() + "."); log.error(e.getMessage()); log.error(e.getStackTrace()); System.exit(1); } context.complete(); if (out instanceof FileOutputStream) { out.close(); } } }