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.collect.Maps.newTreeMap;
  21 import static java.lang.String.format;
  22 import static java.util.Optional.empty;
  23 import static java.util.Optional.of;
  24
  25 import java.util.HashMap;
  26 import java.util.Map;
  27 import java.util.Map.Entry;
  28 import java.util.Optional;
  29 import java.util.SortedMap;
  30
  31 import net.pterodactylus.rhynodge.Filter;
  32 import net.pterodactylus.rhynodge.Query;
  33 import net.pterodactylus.rhynodge.Reaction;
  34 import net.pterodactylus.rhynodge.Trigger;
  35 import net.pterodactylus.rhynodge.states.AbstractState;
  36 import net.pterodactylus.rhynodge.states.FailedState;
  37 import net.pterodactylus.rhynodge.states.StateManager;
  38
  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                         net.pterodactylus.rhynodge.State state = runReaction(nextReaction, reactionName);
 136                         logger.debug(format("State is %s.", state));
 137
 138                         /* convert states. */
 139                         for (Filter filter : nextReaction.get().getReaction().filters()) {
 140                                 if (state.success()) {
 141                                         state = filter.filter(state);
 142                                 }
 143                         }
 144                         if (!state.success()) {
 145                                 state.setFailCount(lastStateFailCount + 1);
 146                         }
 147                         Optional<net.pterodactylus.rhynodge.State> lastSuccessfulState = stateManager.loadLastSuccessfulState(reactionName);
 148
 149                         /* merge states. */
 150                         boolean triggerHit = false;
 151                         Trigger trigger = nextReaction.get().getReaction().trigger();
 152                         if (lastSuccessfulState.isPresent() && lastSuccessfulState.get().success() && state.success()) {
 153                                 net.pterodactylus.rhynodge.State newState = trigger.mergeStates(lastSuccessfulState.get(), state);
 154
 155                                 /* save new state. */
 156                                 stateManager.saveState(reactionName, newState);
 157
 158                                 triggerHit = trigger.triggers();
 159                         } else {
 160                                 /* save first or error state. */
 161                                 stateManager.saveState(reactionName, state);
 162                         }
 163
 164                         /* run action if trigger was hit. */
 165                         logger.debug(format("Trigger was hit: %s.", triggerHit));
 166                         if (triggerHit) {
 167                                 logger.info("Executing Action...");
 168                                 nextReaction.get().getReaction().action().execute(trigger.output(nextReaction.get().getReaction()));
 169                         }
 170
 171                 }
 172         }
 173
 174         private net.pterodactylus.rhynodge.State runReaction(Optional<NextReaction> nextReaction, String reactionName) {
 175                 logger.info(format("Running Query for %s...", reactionName));
 176                 Query query = nextReaction.get().getReaction().query();
 177                 net.pterodactylus.rhynodge.State state;
 178                 try {
 179                         logger.debug("Querying system...");
 180                         state = query.state();
 181                         if (state == null) {
 182                                 state = FailedState.INSTANCE;
 183                         }
 184                         logger.debug("System queried.");
 185                 } catch (Throwable t1) {
 186                         logger.warn("Querying system failed!", t1);
 187                         state = new AbstractState(t1) {
 188                         };
 189                 }
 190                 return state;
 191         }
 192
 193         private void waitForNextReactionToStart(Optional<NextReaction> nextReaction, long waitTime) {
 194                 synchronized (reactions) {
 195                         try {
 196                                 logger.info(format("Waiting until %tc.", nextReaction.get().getNextTime()));
 197                                 reactions.wait(waitTime);
 198                         } catch (InterruptedException ie1) {
 199                                 /* we’re looping! */
 200                         }
 201                 }
 202         }
 203
 204         private Optional<NextReaction> getNextReaction() {
 205                 while (isRunning()) {
 206                         synchronized (reactions) {
 207                                 if (reactions.isEmpty()) {
 208                                         logger.debug("Sleeping while no Reactions available.");
 209                                         try {
 210                                                 reactions.wait();
 211                                         } catch (InterruptedException ie1) {
 212                                                 /* ignore, we’re looping anyway. */
 213                                         }
 214                                         continue;
 215                                 }
 216                         }
 217
 218                         /* find next reaction. */
 219                         SortedMap<Long, Pair<String, Reaction>> nextReactions = newTreeMap();
 220                         synchronized (reactions) {
 221                                 for (Entry<String, Reaction> reactionEntry : reactions.entrySet()) {
 222                                         Optional<net.pterodactylus.rhynodge.State> state = stateManager.loadLastState(reactionEntry.getKey());
 223                                         long stateTime = state.isPresent() ? state.get().time() : 0;
 224                                         nextReactions.put(stateTime + reactionEntry.getValue().updateInterval(), Pair.of(reactionEntry.getKey(), reactionEntry.getValue()));
 225                                 }
 226                                 Pair<String, Reaction> keyReaction = nextReactions.get(nextReactions.firstKey());
 227                                 return of(new NextReaction(keyReaction.getKey(), keyReaction.getValue(), nextReactions.firstKey()));
 228                         }
 229                 }
 230                 return empty();
 231         }
 232
 233         private static class NextReaction {
 234
 235                 private final String key;
 236                 private final Reaction reaction;
 237                 private final long nextTime;
 238
 239                 private NextReaction(String key, Reaction reaction, long nextTime) {
 240                         this.key = key;
 241                         this.reaction = reaction;
 242                         this.nextTime = nextTime;
 243                 }
 244
 245                 public String getKey() {
 246                         return key;
 247                 }
 248
 249                 public Reaction getReaction() {
 250                         return reaction;
 251                 }
 252
 253                 public long getNextTime() {
 254                         return nextTime;
 255                 }
 256
 257         }
 258
 259 }