001 package de.deepamehta.plugins.time;
002
003 import de.deepamehta.plugins.time.service.TimeService;
004
005 import de.deepamehta.core.Association;
006 import de.deepamehta.core.DeepaMehtaObject;
007 import de.deepamehta.core.Topic;
008 import de.deepamehta.core.model.AssociationModel;
009 import de.deepamehta.core.model.ChildTopicsModel;
010 import de.deepamehta.core.model.TopicModel;
011 import de.deepamehta.core.osgi.PluginActivator;
012 import de.deepamehta.core.service.event.PostCreateAssociationListener;
013 import de.deepamehta.core.service.event.PostCreateTopicListener;
014 import de.deepamehta.core.service.event.PostUpdateAssociationListener;
015 import de.deepamehta.core.service.event.PostUpdateTopicListener;
016 import de.deepamehta.core.service.event.PostUpdateTopicRequestListener;
017 import de.deepamehta.core.service.event.PreSendAssociationListener;
018 import de.deepamehta.core.service.event.PreSendTopicListener;
019 import de.deepamehta.core.service.event.ServiceResponseFilterListener;
020
021 // ### TODO: hide Jersey internals. Move to JAX-RS 2.0.
022 import com.sun.jersey.spi.container.ContainerResponse;
023
024 import javax.ws.rs.GET;
025 import javax.ws.rs.Path;
026 import javax.ws.rs.PathParam;
027 import javax.ws.rs.Produces;
028 import javax.ws.rs.Consumes;
029 import javax.ws.rs.core.MultivaluedMap;
030
031 import java.text.DateFormat;
032 import java.text.SimpleDateFormat;
033 import java.util.Collection;
034 import java.util.LinkedHashSet;
035 import java.util.List;
036 import java.util.Locale;
037 import java.util.Set;
038 import java.util.TimeZone;
039 import java.util.logging.Logger;
040
041
042
043 @Path("/time")
044 @Consumes("application/json")
045 @Produces("application/json")
046 public class TimePlugin extends PluginActivator implements TimeService, PostCreateTopicListener,
047 PostCreateAssociationListener,
048 PostUpdateTopicListener,
049 PostUpdateTopicRequestListener,
050 PostUpdateAssociationListener,
051 PreSendTopicListener,
052 PreSendAssociationListener,
053 ServiceResponseFilterListener {
054
055 // ------------------------------------------------------------------------------------------------------- Constants
056
057 private static String PROP_URI_CREATED = "dm4.time.created";
058 private static String PROP_URI_MODIFIED = "dm4.time.modified";
059
060 private static String HEADER_LAST_MODIFIED = "Last-Modified";
061
062 // ---------------------------------------------------------------------------------------------- Instance Variables
063
064 private DateFormat rfc2822;
065
066 private Logger logger = Logger.getLogger(getClass().getName());
067
068 // -------------------------------------------------------------------------------------------------- Public Methods
069
070
071
072 // **********************************
073 // *** TimeService Implementation ***
074 // **********************************
075
076
077
078 // === Timestamps ===
079
080 // Note: the timestamp getters must return 0 as default. Before we used -1 but Jersey's evaluatePreconditions()
081 // does not work as expected when called with a negative value which is not dividable by 1000.
082
083 @Override
084 public long getCreationTime(DeepaMehtaObject object) {
085 return object.hasProperty(PROP_URI_CREATED) ? (Long) object.getProperty(PROP_URI_CREATED) : 0;
086 }
087
088 @Override
089 public long getModificationTime(DeepaMehtaObject object) {
090 return object.hasProperty(PROP_URI_MODIFIED) ? (Long) object.getProperty(PROP_URI_MODIFIED) : 0;
091 }
092
093
094
095 // === Retrieval ===
096
097 @GET
098 @Path("/from/{from}/to/{to}/topics/created")
099 @Override
100 public Collection<Topic> getTopicsByCreationTime(@PathParam("from") long from,
101 @PathParam("to") long to) {
102 return dms.getTopicsByPropertyRange(PROP_URI_CREATED, from, to);
103 }
104
105 @GET
106 @Path("/from/{from}/to/{to}/topics/modified")
107 @Override
108 public Collection<Topic> getTopicsByModificationTime(@PathParam("from") long from,
109 @PathParam("to") long to) {
110 return dms.getTopicsByPropertyRange(PROP_URI_MODIFIED, from, to);
111 }
112
113 @GET
114 @Path("/from/{from}/to/{to}/assocs/created")
115 @Override
116 public Collection<Association> getAssociationsByCreationTime(@PathParam("from") long from,
117 @PathParam("to") long to) {
118 return dms.getAssociationsByPropertyRange(PROP_URI_CREATED, from, to);
119 }
120
121 @GET
122 @Path("/from/{from}/to/{to}/assocs/modified")
123 @Override
124 public Collection<Association> getAssociationsByModificationTime(@PathParam("from") long from,
125 @PathParam("to") long to) {
126 return dms.getAssociationsByPropertyRange(PROP_URI_MODIFIED, from, to);
127 }
128
129
130
131 // ****************************
132 // *** Hook Implementations ***
133 // ****************************
134
135
136
137 @Override
138 public void init() {
139 // create the date format used in HTTP date/time headers, see:
140 // http://www.w3.org/Protocols/rfc2616/rfc2616-sec3.html#sec3.3
141 rfc2822 = DateFormat.getDateTimeInstance(DateFormat.DEFAULT, DateFormat.DEFAULT, Locale.ENGLISH);
142 rfc2822.setTimeZone(TimeZone.getTimeZone("GMT+00:00"));
143 ((SimpleDateFormat) rfc2822).applyPattern("EEE, dd MMM yyyy HH:mm:ss 'GMT'");
144 }
145
146
147
148 // ********************************
149 // *** Listener Implementations ***
150 // ********************************
151
152
153
154 @Override
155 public void postCreateTopic(Topic topic) {
156 storeTimestamps(topic);
157 }
158
159 @Override
160 public void postCreateAssociation(Association assoc) {
161 storeTimestamps(assoc);
162 }
163
164 @Override
165 public void postUpdateTopic(Topic topic, TopicModel newModel, TopicModel oldModel) {
166 storeTimestamp(topic);
167 }
168
169 @Override
170 public void postUpdateAssociation(Association assoc, AssociationModel oldModel) {
171 storeTimestamp(assoc);
172 }
173
174 // ---
175
176 @Override
177 public void postUpdateTopicRequest(Topic topic) {
178 storeParentsTimestamp(topic);
179 }
180
181 // ---
182
183 @Override
184 public void preSendTopic(Topic topic) {
185 enrichWithTimestamp(topic);
186 }
187
188 @Override
189 public void preSendAssociation(Association assoc) {
190 enrichWithTimestamp(assoc);
191 }
192
193 // ---
194
195 @Override
196 public void serviceResponseFilter(ContainerResponse response) {
197 DeepaMehtaObject object = responseObject(response);
198 if (object != null) {
199 long modified = enrichWithTimestamp(object);
200 setLastModifiedHeader(response, modified);
201 }
202 }
203
204
205
206 // ------------------------------------------------------------------------------------------------- Private Methods
207
208 private void storeTimestamps(DeepaMehtaObject object) {
209 long time = System.currentTimeMillis();
210 storeCreationTime(object, time);
211 storeModificationTime(object, time);
212 }
213
214 private void storeTimestamp(DeepaMehtaObject object) {
215 long time = System.currentTimeMillis();
216 storeModificationTime(object, time);
217 }
218
219 // ---
220
221 private void storeParentsTimestamp(Topic topic) {
222 for (DeepaMehtaObject object : getParents(topic)) {
223 storeTimestamp(object);
224 }
225 }
226
227 // ---
228
229 private void storeCreationTime(DeepaMehtaObject object, long time) {
230 storeTime(object, PROP_URI_CREATED, time);
231 }
232
233 private void storeModificationTime(DeepaMehtaObject object, long time) {
234 storeTime(object, PROP_URI_MODIFIED, time);
235 }
236
237 // ---
238
239 private void storeTime(DeepaMehtaObject object, String propUri, long time) {
240 object.setProperty(propUri, time, true); // addToIndex=true
241 }
242
243 // ===
244
245 // ### FIXME: copy in CachingPlugin
246 private DeepaMehtaObject responseObject(ContainerResponse response) {
247 Object entity = response.getEntity();
248 return entity instanceof DeepaMehtaObject ? (DeepaMehtaObject) entity : null;
249 }
250
251 private long enrichWithTimestamp(DeepaMehtaObject object) {
252 long created = getCreationTime(object);
253 long modified = getModificationTime(object);
254 ChildTopicsModel childTopics = object.getChildTopics().getModel();
255 childTopics.put(PROP_URI_CREATED, created);
256 childTopics.put(PROP_URI_MODIFIED, modified);
257 return modified;
258 }
259
260 // ---
261
262 private void setLastModifiedHeader(ContainerResponse response, long time) {
263 setHeader(response, HEADER_LAST_MODIFIED, rfc2822.format(time));
264 }
265
266 // ### FIXME: copy in CachingPlugin
267 private void setHeader(ContainerResponse response, String header, String value) {
268 MultivaluedMap headers = response.getHttpHeaders();
269 //
270 if (headers.containsKey(header)) {
271 throw new RuntimeException("Response already has a \"" + header + "\" header");
272 }
273 //
274 headers.putSingle(header, value);
275 }
276
277 // ---
278
279 /**
280 * Returns all parent topics/associations of the given topic (recursively).
281 * Traversal is informed by the "parent" and "child" role types.
282 * Traversal stops when no parent exists or when an association is met.
283 */
284 private Set<DeepaMehtaObject> getParents(Topic topic) {
285 Set<DeepaMehtaObject> parents = new LinkedHashSet();
286 //
287 List<? extends Topic> parentTopics = topic.getRelatedTopics((String) null, "dm4.core.child",
288 "dm4.core.parent", null, 0).getItems();
289 List<? extends Association> parentAssocs = topic.getRelatedAssociations(null, "dm4.core.child",
290 "dm4.core.parent", null).getItems();
291 parents.addAll(parentTopics);
292 parents.addAll(parentAssocs);
293 //
294 for (Topic parentTopic : parentTopics) {
295 parents.addAll(getParents(parentTopic));
296 }
297 //
298 return parents;
299 }
300 }