Java tutorial
/* * #! * Ontopia Engine * #- * Copyright (C) 2001 - 2013 The Ontopia Project * #- * Licensed under the Apache 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.apache.org/licenses/LICENSE-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 net.ontopia.topicmaps.xml; import java.io.File; import java.io.IOException; import java.io.InputStream; import java.io.Reader; import java.net.MalformedURLException; import java.net.URL; import java.util.Collection; import java.util.Collections; import java.util.HashMap; import java.util.HashSet; import java.util.Iterator; import java.util.Map; import net.ontopia.infoset.core.LocatorIF; import net.ontopia.infoset.impl.basic.URILocator; import net.ontopia.topicmaps.core.AssociationIF; import net.ontopia.topicmaps.core.AssociationRoleIF; import net.ontopia.topicmaps.core.OccurrenceIF; import net.ontopia.topicmaps.core.ReifiableIF; import net.ontopia.topicmaps.core.ScopedIF; import net.ontopia.topicmaps.core.TMObjectIF; import net.ontopia.topicmaps.core.TopicIF; import net.ontopia.topicmaps.core.TopicMapBuilderIF; import net.ontopia.topicmaps.core.TopicMapIF; import net.ontopia.topicmaps.core.TopicMapReaderIF; import net.ontopia.topicmaps.core.TopicMapStoreIF; import net.ontopia.topicmaps.core.TopicNameIF; import net.ontopia.topicmaps.core.VariantNameIF; import net.ontopia.topicmaps.impl.basic.InMemoryTopicMapStore; import net.ontopia.topicmaps.utils.ClassInstanceUtils; import net.ontopia.topicmaps.utils.MergeUtils; import net.ontopia.utils.OntopiaRuntimeException; import net.ontopia.xml.AbstractXMLFormatReader; import net.ontopia.xml.DefaultXMLReaderFactory; import net.ontopia.xml.ValidatingContentHandler; import org.apache.commons.lang3.StringUtils; import org.xml.sax.Attributes; import org.xml.sax.ContentHandler; import org.xml.sax.InputSource; import org.xml.sax.SAXException; import org.xml.sax.XMLReader; /** * PUBLIC: A reader importing topic maps (or fragments) from the * TM/XML syntax. * * @since 3.1 */ public class TMXMLReader extends AbstractXMLFormatReader implements TopicMapReaderIF { public static final String PROPERTY_VALIDATE = "validate"; private boolean validate = true; // constants for state private static final int START = 0; // before document element private static final int TOP = 1; // inside doc elem, outside topic private static final int TOPIC = 2; // inside topic private static final int IDENTIFIER = 3; // inside tm:identifier private static final int MAYBETOPICNAME = 4; // inside characteristic private static final int BASENAME = 5; // ... private static final int TOPICNAME = 6; private static final int VARIANT = 7; private static final int ASSOCIATION = 8; private static final int ROLE = 9; // --- Constructors /** * PUBLIC: Creates a reader reading from the given url. */ public TMXMLReader(URL url) throws MalformedURLException { super(url); } public TMXMLReader(URL url, LocatorIF base_address) { super(url, base_address); } /** * PUBLIC: Creates a reader reading from the given file name. */ public TMXMLReader(File file) throws MalformedURLException { super(file); } /** * PUBLIC: Creates a reader reading from the given Reader using * the specified base address. */ public TMXMLReader(Reader reader, LocatorIF base_address) { super(reader, base_address); } /** * PUBLIC: Creates a reader reading from the given InputStream using * the specified base address. */ public TMXMLReader(InputStream stream, LocatorIF base_address) { super(stream, base_address); } /** * PUBLIC: Creates a reader reading from the given location, using a * different base address. */ public TMXMLReader(InputSource source, LocatorIF base) { super(source, base); } // --- Accessors public boolean getValidate() { return validate; } public void setValidate(boolean validate) { this.validate = validate; } // --- TopicMapReaderIF implementation @Override public TopicMapIF read() throws IOException { InMemoryTopicMapStore store = new InMemoryTopicMapStore(); store.setBaseAddress(base_address); TopicMapIF topicmap = store.getTopicMap(); importInto(topicmap); ClassInstanceUtils.resolveAssociations1(topicmap); ClassInstanceUtils.resolveAssociations2(topicmap); return topicmap; } @Override public void importInto(TopicMapIF topicmap) throws IOException { // Check that store is ok TopicMapStoreIF store = topicmap.getStore(); if (store == null) throw new IOException("Topic map not connected to a store."); XMLReader parser; try { parser = DefaultXMLReaderFactory.createXMLReader(); } catch (SAXException e) { throw new IOException("Problems occurred when creating SAX2 XMLReader: " + e.getMessage()); } // Register content handlers ContentHandler handler = new TMXMLContentHandler(topicmap, base_address); if (validate) handler = new ValidatingContentHandler(handler, getTMXMLSchema(), true); parser.setContentHandler(handler); // Parse input source try { parser.parse(source); } catch (SAXException e) { if (e.getException() instanceof IOException) throw (IOException) e.getException(); throw new OntopiaRuntimeException(e); //throw new IOException("XML related problem: " + e.toString()); } } @Override public Collection readAll() throws IOException { return Collections.singleton(read()); } // --- ContentHandler final class TMXMLContentHandler extends AbstractTopicMapContentHandler { private Map nsprefixes; private TopicMapIF topicmap; private int state; private TopicMapBuilderIF builder; private TopicIF topic; private StringBuilder buffer; private TopicNameIF basename; private AssociationIF association; private boolean isuri; private String reifier; private TopicIF type; // used for topic names only // carryovers from start tag to object creation private Collection scope; private String datatype; public TMXMLContentHandler(TopicMapIF topicmap, LocatorIF base) { super(base); this.topicmap = topicmap; this.builder = topicmap.getBuilder(); this.state = START; this.buffer = new StringBuilder(); this.nsprefixes = new HashMap(); } @Override public void startElement(String uri, String name, String qName, Attributes atts) throws SAXException { //System.out.println("<" + name + ": " + state); // try { switch (state) { case START: // before document element // this is the document element, of which we only want the id, if given handleReifier(topicmap, atts); state = TOP; break; case TOP: // inside doc elem, outside topic // this has to be the start element of a topic topic = getTopicById(atts.getValue("", "id")); TopicIF ttype = getType(uri, name); if (ttype != null) topic.addType(ttype); state = TOPIC; break; case TOPIC: // this has to be some property of the topic if (TMXMLWriter.NS_TM.equals(uri) && ("identifier".equals(name) || "locator".equals(name))) state = IDENTIFIER; else if (atts.getValue("", "role") != null) { // it's an association, of some kind // let's make association and role played by this topic association = builder.makeAssociation(getType(uri, name)); TopicIF roletype = getTopicByAttRef(atts.getValue("", "role")); builder.makeAssociationRole(association, roletype, topic); scope = getScope(atts); addScope(association); handleReifier(association, atts); if (atts.getValue("", "topicref") != null) { // binary association TopicIF other = getTopicByAttRef(atts.getValue("", "topicref")); roletype = getTopicByAttRef(atts.getValue("", "otherrole")); builder.makeAssociationRole(association, roletype, other); } // if unary or binary association: nothing more happens // if n-ary association: child elements for roles appear state = ASSOCIATION; } else { state = MAYBETOPICNAME; scope = getScope(atts); reifier = atts.getValue("", "reifier"); checkDatatype(atts); type = getType(uri, name); // needed if this is a topic name } break; case MAYBETOPICNAME: // could be occurrence, could be topic name if (TMXMLWriter.NS_TM.equals(uri) && "value".equals(name)) { // ok, it was a topic name state = BASENAME; // we were collecting chars in case it was an occurrence; now dump buffer.setLength(0); } break; case TOPICNAME: if (TMXMLWriter.NS_TM.equals(uri) && "variant".equals(name)) { state = VARIANT; scope = getScope(atts); reifier = atts.getValue("", "reifier"); datatype = atts.getValue("", "datatype"); isuri = datatype != null && datatype.equals(TMXMLWriter.XSD_ANYURI); } break; case ASSOCIATION: // this must be the role element inside an association element TopicIF roletype = getType(uri, name); TopicIF other = getTopicByAttRef(atts.getValue("", "topicref")); AssociationRoleIF role = builder.makeAssociationRole(association, roletype, other); handleReifier(role, atts); state = ROLE; break; } // } catch (Throwable e) { // e.printStackTrace(); // throw new OntopiaRuntimeException(e); // } } @Override public void characters(char ch[], int start, int length) { if (state == IDENTIFIER || state == BASENAME || state == VARIANT || state == MAYBETOPICNAME) buffer.append(ch, start, length); } @Override public void endElement(String uri, String name, String qName) throws SAXException { //System.out.println("</" + name + ": " + state); try { switch (state) { case TOP: state = START; break; case TOPIC: state = TOP; break; case IDENTIFIER: state = TOPIC; LocatorIF loc = createLocator(buffer.toString()); buffer.setLength(0); if ("identifier".equals(name)) registerSubjectIndicator(topic, loc); else if ("locator".equals(name)) registerSubjectLocator(topic, loc); break; case BASENAME: state = TOPICNAME; basename = builder.makeTopicName(topic, type, buffer.toString()); addScope(basename); handleReifier(basename, reifier); reifier = null; buffer.setLength(0); break; case VARIANT: state = TOPICNAME; VariantNameIF vn; if (isuri) { try { vn = builder.makeVariantName(basename, new URILocator(buffer.toString())); } catch (MalformedURLException e) { throw new SAXException("Invalid URI for variant name", e); } } else { vn = builder.makeVariantName(basename, buffer.toString()); } addScope(vn); handleReifier(vn, reifier); reifier = null; buffer.setLength(0); break; case TOPICNAME: state = TOPIC; break; case MAYBETOPICNAME: // it turned out to be an occurrence (because we're seeing the end of // the element and haven't seen <value>) state = TOPIC; if (datatype == null) datatype = TMXMLWriter.XSD_STRING; OccurrenceIF occ = builder.makeOccurrence(topic, getType(uri, name), buffer.toString(), createLocator(datatype)); buffer.setLength(0); addScope(occ); handleReifier(occ, reifier); reifier = null; break; case ASSOCIATION: state = TOPIC; break; case ROLE: state = ASSOCIATION; break; } } catch (Exception e) { throw new OntopiaRuntimeException(e); } } @Override public void startPrefixMapping(String prefix, String uri) { nsprefixes.put(prefix, uri); } @Override public void endPrefixMapping(String prefix) { nsprefixes.remove(prefix); } private TopicIF getType(String uri, String name) throws SAXException { if (uri == null || uri.isEmpty()) return getTopicById(name); if (TMXMLWriter.NS_TM.equals(uri) && "topic".equals(name)) return null; // element for typeless construct try { return getTopicBySubjectIdentifier(new URILocator(uri + name)); } catch (java.net.MalformedURLException e) { throw new SAXException("Invalid URI: " + uri + name); } } private Collection getScope(Attributes atts) { String value = atts.getValue("", "scope"); if (value == null) return Collections.EMPTY_SET; String[] tokens = StringUtils.split(value); Collection scope = new HashSet(tokens.length); for (int ix = 0; ix < tokens.length; ix++) scope.add(getTopicByAttRef(tokens[ix])); return scope; } private void addScope(ScopedIF scoped) { Iterator it = scope.iterator(); while (it.hasNext()) scoped.addTheme((TopicIF) it.next()); scope = null; } private void checkDatatype(Attributes atts) { datatype = atts.getValue("", "datatype"); } private TopicIF getTopicByAttRef(String attref) { if (attref.indexOf(':') == -1) return getTopicById(attref); else return getTopicByQName(attref); } private TopicIF getTopicById(String id) { LocatorIF loc = createLocator('#' + id); TopicIF topic = (TopicIF) topicmap.getObjectByItemIdentifier(loc); if (topic == null) { topic = builder.makeTopic(); registerSourceLocator(topic, id); } return topic; } private TopicIF getTopicBySubjectIdentifier(LocatorIF psi) { TopicIF type = topicmap.getTopicBySubjectIdentifier(psi); if (type == null) { type = builder.makeTopic(); registerSubjectIndicator(type, psi); } return type; } private TopicIF getTopicByQName(String qname) { int pos = qname.indexOf(':'); String prefix = qname.substring(0, pos); String local = qname.substring(pos + 1); if (!nsprefixes.containsKey(prefix)) throw new OntopiaRuntimeException("Undeclared namespace prefix " + prefix + " in " + qname); try { LocatorIF psi = new URILocator(nsprefixes.get(prefix) + local); return getTopicBySubjectIdentifier(psi); } catch (java.net.MalformedURLException e) { throw new OntopiaRuntimeException( "Invalid namespace URI from qname " + qname + ": " + prefix + local); } } private void registerSubjectIndicator(TopicIF topic, LocatorIF psi) { TopicIF other = topicmap.getTopicBySubjectIdentifier(psi); if (other == null) { topic.addSubjectIdentifier(psi); return; } if (!other.equals(topic)) MergeUtils.mergeInto(topic, other); } // stolen from XTMContentHandler protected void registerSourceLocator(TMObjectIF tmobject, String id) { // No need to register source locator if id is null if (id == null) return; tmobject.addItemIdentifier(createLocator('#' + id)); } protected void registerSubjectLocator(TopicIF topic, LocatorIF loc) { TopicIF other = topicmap.getTopicBySubjectLocator(loc); if (other == null) { topic.addSubjectLocator(loc); return; } if (other != topic) MergeUtils.mergeInto(topic, other); } // stolen from XTMContentHandler protected LocatorIF createLocator(String address) { if (address.length() == 0) return doc_address; else return doc_address.resolveAbsolute(address); } private void handleReifier(ReifiableIF reifiable, Attributes atts) { handleReifier(reifiable, atts.getValue("", "reifier")); } private void handleReifier(ReifiableIF reifiable, String ref) { if (ref == null) return; LocatorIF base = doc_address; TopicIF reifier = getTopicByAttRef(ref); reify(reifiable, reifier); } private void reify(ReifiableIF reifiable, TopicIF reifier) { reifiable.setReifier(reifier); } } private InputSource getTMXMLSchema() throws IOException { ClassLoader cl = Thread.currentThread().getContextClassLoader(); InputStream i = cl.getResourceAsStream("net/ontopia/topicmaps/xml/tmxml.rnc"); return new InputSource(i); } /** * Sets additional properties for the TMXMLReader. Only accepts the property "validate", which * corresponds to the {@link #setValidate(boolean)} method. Only accepts a boolean value. * @param properties */ @Override public void setAdditionalProperties(Map<String, Object> properties) { Object value = properties.get(PROPERTY_VALIDATE); if ((value != null) && (value instanceof Boolean)) { setValidate((Boolean) value); } } }