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.CompositeValueModel;
010 import de.deepamehta.core.model.TopicModel;
011 import de.deepamehta.core.osgi.PluginActivator;
012 import de.deepamehta.core.service.ClientState;
013 import de.deepamehta.core.service.Directives;
014 import de.deepamehta.core.service.event.PostCreateAssociationListener;
015 import de.deepamehta.core.service.event.PostCreateTopicListener;
016 import de.deepamehta.core.service.event.PostUpdateAssociationListener;
017 import de.deepamehta.core.service.event.PostUpdateTopicListener;
018 import de.deepamehta.core.service.event.PostUpdateTopicRequestListener;
019 import de.deepamehta.core.service.event.PreSendAssociationListener;
020 import de.deepamehta.core.service.event.PreSendTopicListener;
021 import de.deepamehta.core.service.event.ServiceResponseFilterListener;
022
023 // ### TODO: hide Jersey internals. Move to JAX-RS 2.0.
024 import com.sun.jersey.spi.container.ContainerResponse;
025
026 import javax.ws.rs.GET;
027 import javax.ws.rs.Path;
028 import javax.ws.rs.PathParam;
029 import javax.ws.rs.Produces;
030 import javax.ws.rs.Consumes;
031 import javax.ws.rs.core.MultivaluedMap;
032
033 import java.text.DateFormat;
034 import java.text.SimpleDateFormat;
035 import java.util.Collection;
036 import java.util.LinkedHashSet;
037 import java.util.List;
038 import java.util.Locale;
039 import java.util.Set;
040 import java.util.TimeZone;
041 import java.util.logging.Logger;
042
043
044
045 @Path("/time")
046 @Consumes("application/json")
047 @Produces("application/json")
048 public class TimePlugin extends PluginActivator implements TimeService, PostCreateTopicListener,
049 PostCreateAssociationListener,
050 PostUpdateTopicListener,
051 PostUpdateTopicRequestListener,
052 PostUpdateAssociationListener,
053 PreSendTopicListener,
054 PreSendAssociationListener,
055 ServiceResponseFilterListener {
056
057 // ------------------------------------------------------------------------------------------------------- Constants
058
059 private static String PROP_URI_CREATED = "dm4.time.created";
060 private static String PROP_URI_MODIFIED = "dm4.time.modified";
061
062 private static String HEADER_LAST_MODIFIED = "Last-Modified";
063
064 // ---------------------------------------------------------------------------------------------- Instance Variables
065
066 private DateFormat rfc2822;
067
068 private Logger logger = Logger.getLogger(getClass().getName());
069
070 // -------------------------------------------------------------------------------------------------- Public Methods
071
072
073
074 // **********************************
075 // *** TimeService Implementation ***
076 // **********************************
077
078
079
080 // === Timestamps ===
081
082 // Note: the timestamp getters must return 0 as default. Before we used -1 but Jersey's evaluatePreconditions()
083 // does not work as expected when called with a negative value which is not dividable by 1000.
084
085 @Override
086 public long getCreationTime(DeepaMehtaObject object) {
087 return object.hasProperty(PROP_URI_CREATED) ? (Long) object.getProperty(PROP_URI_CREATED) : 0;
088 }
089
090 @Override
091 public long getModificationTime(DeepaMehtaObject object) {
092 return object.hasProperty(PROP_URI_MODIFIED) ? (Long) object.getProperty(PROP_URI_MODIFIED) : 0;
093 }
094
095
096
097 // === Retrieval ===
098
099 @GET
100 @Path("/from/{from}/to/{to}/topics/created")
101 @Override
102 public Collection<Topic> getTopicsByCreationTime(@PathParam("from") long from,
103 @PathParam("to") long to) {
104 return dms.getTopicsByPropertyRange(PROP_URI_CREATED, from, to);
105 }
106
107 @GET
108 @Path("/from/{from}/to/{to}/topics/modified")
109 @Override
110 public Collection<Topic> getTopicsByModificationTime(@PathParam("from") long from,
111 @PathParam("to") long to) {
112 return dms.getTopicsByPropertyRange(PROP_URI_MODIFIED, from, to);
113 }
114
115 @GET
116 @Path("/from/{from}/to/{to}/assocs/created")
117 @Override
118 public Collection<Association> getAssociationsByCreationTime(@PathParam("from") long from,
119 @PathParam("to") long to) {
120 return dms.getAssociationsByPropertyRange(PROP_URI_CREATED, from, to);
121 }
122
123 @GET
124 @Path("/from/{from}/to/{to}/assocs/modified")
125 @Override
126 public Collection<Association> getAssociationsByModificationTime(@PathParam("from") long from,
127 @PathParam("to") long to) {
128 return dms.getAssociationsByPropertyRange(PROP_URI_MODIFIED, from, to);
129 }
130
131
132
133 // ****************************
134 // *** Hook Implementations ***
135 // ****************************
136
137
138
139 @Override
140 public void init() {
141 // create the date format used in HTTP date/time headers, see:
142 // http://www.w3.org/Protocols/rfc2616/rfc2616-sec3.html#sec3.3
143 rfc2822 = DateFormat.getDateTimeInstance(DateFormat.DEFAULT, DateFormat.DEFAULT, Locale.ENGLISH);
144 rfc2822.setTimeZone(TimeZone.getTimeZone("GMT+00:00"));
145 ((SimpleDateFormat) rfc2822).applyPattern("EEE, dd MMM yyyy HH:mm:ss 'GMT'");
146 }
147
148
149
150 // ********************************
151 // *** Listener Implementations ***
152 // ********************************
153
154
155
156 @Override
157 public void postCreateTopic(Topic topic, ClientState clientState, Directives directives) {
158 storeTimestamps(topic);
159 }
160
161 @Override
162 public void postCreateAssociation(Association assoc, ClientState clientState, Directives directives) {
163 storeTimestamps(assoc);
164 }
165
166 @Override
167 public void postUpdateTopic(Topic topic, TopicModel newModel, TopicModel oldModel, ClientState clientState,
168 Directives directives) {
169 storeTimestamp(topic);
170 }
171
172 @Override
173 public void postUpdateAssociation(Association assoc, AssociationModel oldModel, ClientState clientState,
174 Directives directives) {
175 storeTimestamp(assoc);
176 }
177
178 // ---
179
180 @Override
181 public void postUpdateTopicRequest(Topic topic) {
182 storeParentsTimestamp(topic);
183 }
184
185 // ---
186
187 @Override
188 public void preSendTopic(Topic topic, ClientState clientState) {
189 enrichWithTimestamp(topic);
190 }
191
192 @Override
193 public void preSendAssociation(Association assoc, ClientState clientState) {
194 enrichWithTimestamp(assoc);
195 }
196
197 // ---
198
199 @Override
200 public void serviceResponseFilter(ContainerResponse response) {
201 DeepaMehtaObject object = responseObject(response);
202 if (object != null) {
203 long modified = enrichWithTimestamp(object);
204 setLastModifiedHeader(response, modified);
205 }
206 }
207
208
209
210 // ------------------------------------------------------------------------------------------------- Private Methods
211
212 private void storeTimestamps(DeepaMehtaObject object) {
213 long time = System.currentTimeMillis();
214 storeCreationTime(object, time);
215 storeModificationTime(object, time);
216 }
217
218 private void storeTimestamp(DeepaMehtaObject object) {
219 long time = System.currentTimeMillis();
220 storeModificationTime(object, time);
221 }
222
223 // ---
224
225 private void storeParentsTimestamp(Topic topic) {
226 for (DeepaMehtaObject object : getParents(topic)) {
227 storeTimestamp(object);
228 }
229 }
230
231 // ---
232
233 private void storeCreationTime(DeepaMehtaObject object, long time) {
234 storeTime(object, PROP_URI_CREATED, time);
235 }
236
237 private void storeModificationTime(DeepaMehtaObject object, long time) {
238 storeTime(object, PROP_URI_MODIFIED, time);
239 }
240
241 // ---
242
243 private void storeTime(DeepaMehtaObject object, String propUri, long time) {
244 object.setProperty(propUri, time, true); // addToIndex=true
245 }
246
247 // ===
248
249 // ### FIXME: copy in CachingPlugin
250 private DeepaMehtaObject responseObject(ContainerResponse response) {
251 Object entity = response.getEntity();
252 return entity instanceof DeepaMehtaObject ? (DeepaMehtaObject) entity : null;
253 }
254
255 private long enrichWithTimestamp(DeepaMehtaObject object) {
256 long created = getCreationTime(object);
257 long modified = getModificationTime(object);
258 CompositeValueModel comp = object.getCompositeValue().getModel();
259 comp.put(PROP_URI_CREATED, created);
260 comp.put(PROP_URI_MODIFIED, modified);
261 return modified;
262 }
263
264 // ---
265
266 private void setLastModifiedHeader(ContainerResponse response, long time) {
267 setHeader(response, HEADER_LAST_MODIFIED, rfc2822.format(time));
268 }
269
270 // ### FIXME: copy in CachingPlugin
271 private void setHeader(ContainerResponse response, String header, String value) {
272 MultivaluedMap headers = response.getHttpHeaders();
273 //
274 if (headers.containsKey(header)) {
275 throw new RuntimeException("Response already has a \"" + header + "\" header");
276 }
277 //
278 headers.putSingle(header, value);
279 }
280
281 // ---
282
283 /**
284 * Returns all parent topics/associations of the given topic (recursively).
285 * Traversal is informed by the "parent" and "child" role types.
286 * Traversal stops when no parent exists or when an association is met.
287 */
288 private Set<DeepaMehtaObject> getParents(Topic topic) {
289 Set<DeepaMehtaObject> parents = new LinkedHashSet();
290 //
291 List<? extends Topic> parentTopics = topic.getRelatedTopics((String) null, "dm4.core.child",
292 "dm4.core.parent", null, false, false, 0).getItems();
293 List<? extends Association> parentAssocs = topic.getRelatedAssociations(null, "dm4.core.child",
294 "dm4.core.parent", null, false, false);
295 parents.addAll(parentTopics);
296 parents.addAll(parentAssocs);
297 //
298 for (Topic parentTopic : parentTopics) {
299 parents.addAll(getParents(parentTopic));
300 }
301 //
302 return parents;
303 }
304 }