Java tutorial
/* * #! * Ontopia TMRAP * #- * 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.utils.tmrap; import java.io.IOException; import java.net.URL; import java.net.URLConnection; import java.net.URLEncoder; import java.util.ArrayList; import java.util.Collection; import java.util.Collections; import java.util.HashSet; import java.util.Iterator; import java.util.List; import net.ontopia.infoset.core.LocatorIF; import net.ontopia.infoset.impl.basic.URILocator; import net.ontopia.topicmaps.core.TopicIF; import net.ontopia.topicmaps.core.TopicMapIF; import net.ontopia.topicmaps.core.TopicMapStoreFactoryIF; import net.ontopia.topicmaps.core.index.ClassInstanceIndexIF; import net.ontopia.topicmaps.impl.basic.InMemoryTopicMapStore; import net.ontopia.topicmaps.utils.CharacteristicUtils; import net.ontopia.topicmaps.utils.MergeUtils; import net.ontopia.topicmaps.utils.NullResolvingExternalReferenceHandler; import net.ontopia.topicmaps.utils.TopicMapSynchronizer; import net.ontopia.topicmaps.xml.XTMTopicMapReader; import net.ontopia.utils.CollectionUtils; import net.ontopia.utils.CompactHashSet; import net.ontopia.utils.OntopiaRuntimeException; import org.apache.commons.lang3.StringUtils; import org.xml.sax.InputSource; /** * EXPERIMENTAL: An implementation that looks up topics on remote * servers using the TM RAP protocol. */ public class RemoteTopicIndex implements TopicIndexIF { public static final String VIRTUAL_URN = "urn:x-oks-virtual:"; protected String editBaseuri; protected String viewBaseuri; protected TopicMapStoreFactoryIF storefactory; protected String tmid; public RemoteTopicIndex(String editBaseuri, String viewBaseuri) { this(editBaseuri, viewBaseuri, new net.ontopia.topicmaps.impl.basic.InMemoryStoreFactory()); } public RemoteTopicIndex(String editBaseuri, String viewBaseuri, TopicMapStoreFactoryIF factory) { this(editBaseuri, viewBaseuri, factory, null); } public RemoteTopicIndex(String editBaseuri, String viewBaseuri, TopicMapStoreFactoryIF factory, String tmid) { this.editBaseuri = editBaseuri; this.viewBaseuri = viewBaseuri; this.storefactory = factory; this.tmid = tmid; } @Override public Collection<TopicIF> getTopics(Collection<LocatorIF> indicators, Collection<LocatorIF> sources, Collection<LocatorIF> subjects) { if (indicators.isEmpty() && sources.isEmpty() && subjects.isEmpty()) return Collections.emptySet(); // lookup or create target topic TopicMapIF targetTopicMap = storefactory.createStore().getTopicMap(); TopicIF targetTopic = createTopic(targetTopicMap, indicators, sources, subjects); // make sure topic knows it's being loaded setLoaded(targetTopic); TopicMapIF sourceTopicMap = new InMemoryTopicMapStore().getTopicMap(); sourceTopicMap.getStore().setBaseAddress(targetTopicMap.getStore().getBaseAddress()); // send get-topic request try { String params = encodeIdentityParameters(indicators, sources, subjects); if (tmid != null) params = "topicmap=" + tmid + "&" + params; loadXTM("get-topic", params, false, sourceTopicMap); } catch (IOException e) { throw new OntopiaRuntimeException(e); } TopicIF sourceTopic = findTopic(sourceTopicMap, indicators, sources, subjects); TopicMapSynchronizer.update(targetTopicMap, sourceTopic); targetTopic = findTopic(targetTopicMap, indicators, sources, subjects); return (targetTopic == null ? null : Collections.singleton(targetTopic)); } private TopicIF createTopic(TopicMapIF tm, Collection<LocatorIF> indicators, Collection<LocatorIF> sources, Collection<LocatorIF> subjects) { // merge all topics that have any of the identities TopicIF topic = null; Collection<TopicIF> existing = findTopics(tm, indicators, sources, subjects); if (!existing.isEmpty()) { Iterator<TopicIF> iter = existing.iterator(); topic = iter.next(); if (iter.hasNext()) { MergeUtils.mergeInto(topic, iter.next()); } } // if no topics was found then create a new one if (topic == null) topic = tm.getBuilder().makeTopic(); // make sure topic has all the identities Iterator<LocatorIF> it = indicators.iterator(); while (it.hasNext()) { LocatorIF loc = it.next(); topic.addSubjectIdentifier(loc); } it = sources.iterator(); while (it.hasNext()) { LocatorIF loc = it.next(); topic.addItemIdentifier(loc); } it = subjects.iterator(); while (it.hasNext()) { LocatorIF subject = it.next(); topic.addSubjectLocator(subject); } return topic; } private TopicIF findTopic(TopicMapIF tm, Collection<LocatorIF> indicators, Collection<LocatorIF> sources, Collection<LocatorIF> subjects) { Iterator<LocatorIF> it = indicators.iterator(); while (it.hasNext()) { LocatorIF loc = it.next(); TopicIF topic = tm.getTopicBySubjectIdentifier(loc); if (topic != null) return topic; } it = sources.iterator(); while (it.hasNext()) { LocatorIF loc = it.next(); TopicIF topic = (TopicIF) tm.getObjectByItemIdentifier(loc); if (topic != null) return topic; else { // Resolve object by object id String address = loc.getAddress(); if (RemoteTopicIndex.isVirtualReference(address)) { if (tmid.equals(RemoteTopicIndex.sourceTopicMapFromVirtualReference(address))) { topic = (TopicIF) tm.getObjectById(RemoteTopicIndex.resolveVirtualReference(address, tmid)); if (topic != null) return topic; } } } } it = subjects.iterator(); while (it.hasNext()) { LocatorIF subject = it.next(); TopicIF topic = tm.getTopicBySubjectLocator(subject); if (topic != null) return topic; } return null; } private Collection<TopicIF> findTopics(TopicMapIF tm, Collection<LocatorIF> indicators, Collection<LocatorIF> sources, Collection<LocatorIF> subjects) { // find all topics that have any of the identities Collection<TopicIF> result = new HashSet<TopicIF>(); Iterator<LocatorIF> it = indicators.iterator(); while (it.hasNext()) { LocatorIF loc = it.next(); TopicIF topic = tm.getTopicBySubjectIdentifier(loc); if (topic != null) result.add(topic); } it = sources.iterator(); while (it.hasNext()) { LocatorIF loc = it.next(); TopicIF topic = (TopicIF) tm.getObjectByItemIdentifier(loc); if (topic != null) result.add(topic); else { // Resolve object by object id String address = loc.getAddress(); if (RemoteTopicIndex.isVirtualReference(address)) { if (tmid.equals(RemoteTopicIndex.sourceTopicMapFromVirtualReference(address))) { topic = (TopicIF) tm.getObjectById(RemoteTopicIndex.resolveVirtualReference(address, tmid)); if (topic != null) result.add(topic); } } } } it = subjects.iterator(); while (it.hasNext()) { LocatorIF subject = it.next(); TopicIF topic = tm.getTopicBySubjectLocator(subject); if (topic != null) result.add(topic); } return result; } private boolean isLoaded(TopicIF topic) { if (topic instanceof net.ontopia.topicmaps.impl.remote.RemoteTopic) return ((net.ontopia.topicmaps.impl.remote.RemoteTopic) topic).isLoaded(); return true; } private void setLoaded(TopicIF topic) { if (topic instanceof net.ontopia.topicmaps.impl.remote.RemoteTopic) { boolean prev = ((net.ontopia.topicmaps.impl.remote.RemoteTopic) topic).isLoaded(); ((net.ontopia.topicmaps.impl.remote.RemoteTopic) topic).setLoaded(true); } } private List<String> getIdPredicates(TopicIF topic, String varname) { List<String> idpredicates = new ArrayList<String>(); Iterator<LocatorIF> ids = topic.getItemIdentifiers().iterator(); while (ids.hasNext()) { LocatorIF loc = ids.next(); String address = loc.getAddress(); if (RemoteTopicIndex.isVirtualReference(address)) { String topicId = RemoteTopicIndex.resolveVirtualReference(address, tmid); if (topicId != null) idpredicates.add("$" + varname + " = @" + topicId); else System.err.println("Cannot resolve virtual reference: " + topicId + " (" + address + ")"); } else { idpredicates.add("item-identifier($" + varname + ", \"" + loc.getAddress() + "\")"); } } ids = topic.getSubjectIdentifiers().iterator(); while (ids.hasNext()) { LocatorIF loc = ids.next(); idpredicates.add("subject-identifier($" + varname + ", \"" + loc.getAddress() + "\")"); } ids = topic.getSubjectLocators().iterator(); while (ids.hasNext()) { LocatorIF loc = ids.next(); idpredicates.add("subject-locator($" + varname + ", \"" + loc.getAddress() + "\")"); } return idpredicates; } @Override public Collection<TopicIF> loadRelatedTopics(Collection<LocatorIF> indicators, Collection<LocatorIF> sources, Collection<LocatorIF> subjects, boolean two_steps) { long start = System.currentTimeMillis(); if (indicators.isEmpty() && sources.isEmpty() && subjects.isEmpty()) return Collections.emptySet(); try { // lookup or create target topic TopicMapIF targetTopicMap = storefactory.createStore().getTopicMap(); TopicIF targetTopic = createTopic(targetTopicMap, indicators, sources, subjects); int count = 0; // build identity predicates List<String> idpredicates_T = getIdPredicates(targetTopic, "T"); if (idpredicates_T.isEmpty()) return Collections.emptySet(); StringBuilder query = new StringBuilder(); query.append("related-to($T1, $T2) :- " + " role-player($R1, $T1), " + " association-role($A, $R1), " + " association-role($A, $R2), " + " $R1 /= $R2, " + " role-player($R2, $T2), " + " $T1 /= $T2 . "); query.append("select $O from "); if (idpredicates_T.size() > 1) query.append(" {"); query.append(StringUtils.join(idpredicates_T, " | ")); if (idpredicates_T.size() > 1) query.append(" }"); query.append(", { "); query.append(" $O = $T | "); query.append(" related-to($T, $O) "); if (two_steps) query.append("| related-to($T, $TMP), related-to($TMP, $O) "); query.append("}?"); TopicMapIF sourceTopicMap = new InMemoryTopicMapStore().getTopicMap(); sourceTopicMap.getStore().setBaseAddress(targetTopicMap.getStore().getBaseAddress()); String params = "syntax=application/x-xtm&tolog=" + URLEncoder.encode(query.toString()); if (tmid != null) params = "topicmap=" + tmid + "&" + params; params += "&compress=true"; loadXTM("get-tolog", params, true, sourceTopicMap); // make sure topic knows it's being loaded TopicIF sourceTopic = findTopic(sourceTopicMap, indicators, sources, subjects); if (!isLoaded(targetTopic)) { setLoaded(targetTopic); TopicMapSynchronizer.update(targetTopicMap, sourceTopic); count++; } // get loaded topics (possibly 2 steps out) Collection<TopicIF> loaded = new CompactHashSet<TopicIF>(); Iterator<TopicIF> riter = CharacteristicUtils.getAssociatedTopics(sourceTopic).iterator(); while (riter.hasNext()) { TopicIF topic = riter.next(); loaded.add(topic); if (two_steps) loaded.addAll(CharacteristicUtils.getAssociatedTopics(topic)); } // move topics over, and mark as loaded transferLoadedTopics(loaded, targetTopicMap); return Collections.singleton(targetTopic); } catch (IOException e) { throw new OntopiaRuntimeException(e); } } @Override public Collection<TopicPage> getTopicPages(Collection<LocatorIF> indicators, Collection<LocatorIF> sources, Collection<LocatorIF> subjects) { Collection<TopicPage> pages = new ArrayList<TopicPage>(); try { String params = encodeIdentityParameters(indicators, sources, subjects); if (tmid != null) params = "topicmap=" + tmid + "&" + params; InputSource src = getInputSource("get-topic-page", params, false); String baseuri = viewBaseuri == null ? editBaseuri : viewBaseuri; LocatorIF base = new URILocator(baseuri + "get-topic-page"); XTMTopicMapReader reader = new XTMTopicMapReader(src, base); reader.setValidation(false); // means we don't need Jing TopicMapIF tm = reader.read(); ClassInstanceIndexIF ix = (ClassInstanceIndexIF) tm .getIndex("net.ontopia.topicmaps.core.index.ClassInstanceIndexIF"); LocatorIF vpsi = new URILocator("http://psi.ontopia.net/tmrap/view-page"); TopicIF vptype = tm.getTopicBySubjectIdentifier(vpsi); if (vptype == null) return pages; Iterator<TopicIF> it = ix.getTopics(vptype).iterator(); while (it.hasNext()) { TopicIF vp = it.next(); LocatorIF subject = CollectionUtils.getFirst(vp.getSubjectLocators()); pages.add(new TopicPage(null, subject.getAddress(), null, null, null)); } } catch (IOException e) { throw new OntopiaRuntimeException(e); } return pages; } @Override public TopicPages getTopicPages2(Collection<LocatorIF> indicators, Collection<LocatorIF> sources, Collection<LocatorIF> subjects) { throw new UnsupportedOperationException("This method is not supported"); } public void loadAssociationTypes(TopicMapIF topicmap) throws IOException { loadQuery(topicmap, "select $T from " + "association($A), " + "type($A, $T)?"); } public void loadTopicTypes(TopicMapIF topicmap) throws IOException { loadQuery(topicmap, "select $T from " + "direct-instance-of($I, $T)?"); } public void loadQuery(TopicMapIF topicmap, String query) throws IOException { // assemble get-tolog request query = URLEncoder.encode(query); TopicMapIF tmptm = new InMemoryTopicMapStore().getTopicMap(); tmptm.getStore().setBaseAddress(topicmap.getStore().getBaseAddress()); String params = "syntax=application/x-xtm&tolog=" + query; if (tmid != null) params = "topicmap=" + tmid + "&" + params; params += "&compress=true"; // send request loadXTM("get-tolog", params, true, tmptm); // collect newly loaded topics Collection<TopicIF> loaded = new ArrayList<TopicIF>(); Iterator<TopicIF> it = tmptm.getTopics().iterator(); while (it.hasNext()) { TopicIF topic = it.next(); if (!(topic.getTypes().isEmpty() && topic.getTopicNames().isEmpty() && topic.getOccurrences().isEmpty() && topic.getRoles().isEmpty())) loaded.add(topic); } // mark as loaded and transfer transferLoadedTopics(loaded, topicmap); } @Override public void close() { // nothing we need to let go of } // Special configuration methods public void setStoreFactory(TopicMapStoreFactoryIF storefactory) { this.storefactory = storefactory; } // Internal methods protected InputSource getInputSource(String method, String params, boolean compress) throws IOException { String baseuri = viewBaseuri == null ? editBaseuri : viewBaseuri; String url = baseuri + method + "?" + params; URLConnection conn = this.getConnection(url, 0); InputSource src = new InputSource(url); if (!compress) { src.setByteStream(conn.getInputStream()); String ctype = conn.getContentType(); if (ctype != null && ctype.startsWith("text/xml")) { int pos = ctype.indexOf("charset="); if (pos != -1) src.setEncoding(ctype.substring(pos + 8)); } } else src.setByteStream(new java.util.zip.GZIPInputStream(conn.getInputStream())); return src; } private URLConnection getConnection(String url, int count) { URLConnection conn = null; try { conn = new URL(url).openConnection(); } catch (IOException e) { if (count < 5) { System.out.println(); System.out.print("getConnection failed - "); System.out.println(count); System.out.println("Trying again ..."); conn = this.getConnection(url, count++); } else { System.out.println("Giving up"); throw new OntopiaRuntimeException(e); } } return conn; } private String encodeIdentityParameters(Collection<LocatorIF> indicators, Collection<LocatorIF> sources, Collection<LocatorIF> subjects) { boolean notfirst = false; StringBuilder buf = new StringBuilder(); Iterator<LocatorIF> it = indicators.iterator(); while (it.hasNext()) { LocatorIF locator = it.next(); if (notfirst) buf.append("&"); buf.append("identifier=" + URLEncoder.encode(locator.getExternalForm())); notfirst = true; } it = sources.iterator(); while (it.hasNext()) { LocatorIF locator = it.next(); if (notfirst) buf.append("&"); buf.append("item=" + URLEncoder.encode(locator.getExternalForm())); notfirst = true; } it = subjects.iterator(); while (it.hasNext()) { LocatorIF locator = it.next(); if (notfirst) buf.append("&"); buf.append("subject=" + URLEncoder.encode(locator.getExternalForm())); } return buf.toString(); } private void loadXTM(String request, String params, boolean compress, TopicMapIF topicmap) throws IOException { InputSource src = getInputSource(request, params, compress); String baseuri = viewBaseuri == null ? editBaseuri : viewBaseuri; LocatorIF base = new URILocator(baseuri + request); XTMTopicMapReader reader = new XTMTopicMapReader(src, base); reader.setExternalReferenceHandler(new NullResolvingExternalReferenceHandler()); reader.setValidation(false); // means we don't need Jing reader.importInto(topicmap); } private void transferLoadedTopics(Collection<TopicIF> loaded, TopicMapIF targetTopicMap) { Iterator<TopicIF> it = loaded.iterator(); while (it.hasNext()) { TopicIF sourceRelated = it.next(); TopicIF targetRelated = createTopic(targetTopicMap, sourceRelated.getSubjectIdentifiers(), sourceRelated.getItemIdentifiers(), sourceRelated.getSubjectLocators()); if (!isLoaded(targetRelated)) { setLoaded(targetRelated); TopicMapSynchronizer.update(targetTopicMap, sourceRelated); } } } //------------------------------------------------------------------- // Virtual locators //-------------------------------------------------------------------- public static boolean isVirtualReference(String address) { return address.startsWith(VIRTUAL_URN); } public static String resolveVirtualReference(String address, String tmid) { String topicMapIndex = RemoteTopicIndex.sourceTopicMapFromVirtualReference(address); if (!topicMapIndex.equals(tmid)) throw new OntopiaRuntimeException( "Topic map IDs do not match, requested=" + topicMapIndex + ", current=" + tmid); return address.substring(address.indexOf('#') + 1); } public static String sourceTopicMapFromVirtualReference(String address) { int index = address.indexOf('#'); return address.substring(RemoteTopicIndex.VIRTUAL_URN.length(), index); } }