Move waiting for next reaction to start into its own method.
[rhynodge.git] / src / main / java / net / pterodactylus / rhynodge / engine / Engine.java
1 /*
2  * Rhynodge - Engine.java - Copyright © 2013 David Roden
3  *
4  * This program is free software: you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License as published by
6  * the Free Software Foundation, either version 3 of the License, or
7  * (at your option) any later version.
8  *
9  * This program is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12  * GNU General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
16  */
17
18 package net.pterodactylus.rhynodge.engine;
19
20 import static com.google.common.base.Optional.absent;
21 import static com.google.common.base.Optional.of;
22 import static com.google.common.collect.Maps.newTreeMap;
23 import static java.lang.String.format;
24
25 import java.util.HashMap;
26 import java.util.Map;
27 import java.util.Map.Entry;
28 import java.util.SortedMap;
29
30 import net.pterodactylus.rhynodge.Filter;
31 import net.pterodactylus.rhynodge.Query;
32 import net.pterodactylus.rhynodge.Reaction;
33 import net.pterodactylus.rhynodge.Trigger;
34 import net.pterodactylus.rhynodge.states.AbstractState;
35 import net.pterodactylus.rhynodge.states.FailedState;
36 import net.pterodactylus.rhynodge.states.StateManager;
37
38 import com.google.common.base.Optional;
39 import com.google.common.util.concurrent.AbstractExecutionThreadService;
40 import org.apache.commons.lang3.tuple.Pair;
41 import org.apache.log4j.Logger;
42
43 /**
44  * Rhynodge main engine.
45  *
46  * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
47  */
48 public class Engine extends AbstractExecutionThreadService {
49
50         /** The logger. */
51         private static final Logger logger = Logger.getLogger(Engine.class);
52
53         /** The state manager. */
54         private final StateManager stateManager;
55
56         /** All defined reactions. */
57         /* synchronize on itself. */
58         private final Map<String, Reaction> reactions = new HashMap<String, Reaction>();
59
60         /**
61          * Creates a new engine.
62          *
63          * @param stateManager
64          *            The state manager
65          */
66         public Engine(StateManager stateManager) {
67                 this.stateManager = stateManager;
68         }
69
70         //
71         // ACCESSORS
72         //
73
74         /**
75          * Adds the given reaction to this engine.
76          *
77          * @param name
78          *            The name of the reaction
79          * @param reaction
80          *            The reaction to add to this engine
81          */
82         public void addReaction(String name, Reaction reaction) {
83                 synchronized (reactions) {
84                         reactions.put(name, reaction);
85                         reactions.notifyAll();
86                 }
87         }
88
89         /**
90          * Removes the reaction with the given name.
91          *
92          * @param name
93          *            The name of the reaction to remove
94          */
95         public void removeReaction(String name) {
96                 synchronized (reactions) {
97                         if (!reactions.containsKey(name)) {
98                                 return;
99                         }
100                         reactions.remove(name);
101                         reactions.notifyAll();
102                 }
103         }
104
105         //
106         // ABSTRACTSERVICE METHODS
107         //
108
109         /**
110          * {@inheritDoc}
111          */
112         @Override
113         public void run() {
114                 while (isRunning()) {
115                         Optional<NextReaction> nextReaction = getNextReaction();
116                         if (!nextReaction.isPresent()) {
117                                 continue;
118                         }
119
120                         String reactionName = nextReaction.get().getKey();
121                         logger.debug(format("Next Reaction: %s.", reactionName));
122
123                         /* wait until the next reaction has to run. */
124                         Optional<net.pterodactylus.rhynodge.State> lastState = stateManager.loadLastState(reactionName);
125                         int lastStateFailCount = lastState.isPresent() ? lastState.get().failCount() : 0;
126                         long waitTime = nextReaction.get().getNextTime() - System.currentTimeMillis();
127                         logger.debug(format("Time to wait for next Reaction: %d millseconds.", waitTime));
128                         if (waitTime > 0) {
129                                 waitForNextReactionToStart(nextReaction, waitTime);
130
131                                 /* re-start loop to check for new reactions. */
132                                 continue;
133                         }
134
135                         /* run reaction. */
136                         logger.info(format("Running Query for %s...", reactionName));
137                         Query query = nextReaction.get().getReaction().query();
138                         net.pterodactylus.rhynodge.State state;
139                         try {
140                                 logger.debug("Querying system...");
141                                 state = query.state();
142                                 if (state == null) {
143                                         state = FailedState.INSTANCE;
144                                 }
145                                 logger.debug("System queried.");
146                         } catch (Throwable t1) {
147                                 logger.warn("Querying system failed!", t1);
148                                 state = new AbstractState(t1) {
149                                         /* no further state. */
150                                 };
151                         }
152                         logger.debug(format("State is %s.", state));
153
154                         /* convert states. */
155                         for (Filter filter : nextReaction.get().getReaction().filters()) {
156                                 if (state.success()) {
157                                         net.pterodactylus.rhynodge.State newState = filter.filter(state);
158                                         //logger.debug(String.format("Old state is %s, new state is %s.", state, newState));
159                                         state = newState;
160                                 }
161                         }
162                         if (!state.success()) {
163                                 state.setFailCount(lastStateFailCount + 1);
164                         }
165                         Optional<net.pterodactylus.rhynodge.State> lastSuccessfulState = stateManager.loadLastSuccessfulState(reactionName);
166
167                         /* merge states. */
168                         boolean triggerHit = false;
169                         Trigger trigger = nextReaction.get().getReaction().trigger();
170                         if (lastSuccessfulState.isPresent() && lastSuccessfulState.get().success() && state.success()) {
171                                 net.pterodactylus.rhynodge.State newState = trigger.mergeStates(lastSuccessfulState.get(), state);
172
173                                 /* save new state. */
174                                 stateManager.saveState(reactionName, newState);
175
176                                 triggerHit = trigger.triggers();
177                         } else {
178                                 /* save first or error state. */
179                                 stateManager.saveState(reactionName, state);
180                         }
181
182                         /* run action if trigger was hit. */
183                         logger.debug(format("Trigger was hit: %s.", triggerHit));
184                         if (triggerHit) {
185                                 logger.info("Executing Action...");
186                                 nextReaction.get().getReaction().action().execute(trigger.output(nextReaction.get().getReaction()));
187                         }
188
189                 }
190         }
191
192         private void waitForNextReactionToStart(Optional<NextReaction> nextReaction, long waitTime) {
193                 synchronized (reactions) {
194                         try {
195                                 logger.info(format("Waiting until %tc.", nextReaction.get().getNextTime()));
196                                 reactions.wait(waitTime);
197                         } catch (InterruptedException ie1) {
198                                 /* we’re looping! */
199                         }
200                 }
201         }
202
203         private Optional<NextReaction> getNextReaction() {
204                 while (isRunning()) {
205                         synchronized (reactions) {
206                                 if (reactions.isEmpty()) {
207                                         logger.debug("Sleeping while no Reactions available.");
208                                         try {
209                                                 reactions.wait();
210                                         } catch (InterruptedException ie1) {
211                                                 /* ignore, we’re looping anyway. */
212                                         }
213                                         continue;
214                                 }
215                         }
216
217                         /* find next reaction. */
218                         SortedMap<Long, Pair<String, Reaction>> nextReactions = newTreeMap();
219                         synchronized (reactions) {
220                                 for (Entry<String, Reaction> reactionEntry : reactions.entrySet()) {
221                                         Optional<net.pterodactylus.rhynodge.State> state = stateManager.loadLastState(reactionEntry.getKey());
222                                         long stateTime = state.isPresent() ? state.get().time() : 0;
223                                         nextReactions.put(stateTime + reactionEntry.getValue().updateInterval(), Pair.of(reactionEntry.getKey(), reactionEntry.getValue()));
224                                 }
225                                 Pair<String, Reaction> keyReaction = nextReactions.get(nextReactions.firstKey());
226                                 return of(new NextReaction(keyReaction.getKey(), keyReaction.getValue(), nextReactions.firstKey()));
227                         }
228                 }
229                 return absent();
230         }
231
232         private static class NextReaction {
233
234                 private final String key;
235                 private final Reaction reaction;
236                 private final long nextTime;
237
238                 private NextReaction(String key, Reaction reaction, long nextTime) {
239                         this.key = key;
240                         this.reaction = reaction;
241                         this.nextTime = nextTime;
242                 }
243
244                 public String getKey() {
245                         return key;
246                 }
247
248                 public Reaction getReaction() {
249                         return reaction;
250                 }
251
252                 public long getNextTime() {
253                         return nextTime;
254                 }
255
256         }
257
258 }