src/main/java/net/pterodactylus/reactor/engine/Engine.java

   1 /*
   2  * Reactor - 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.reactor.engine;
  19
  20 import java.util.HashMap;
  21 import java.util.Map;
  22 import java.util.Map.Entry;
  23 import java.util.SortedMap;
  24
  25 import net.pterodactylus.reactor.Filter;
  26 import net.pterodactylus.reactor.Query;
  27 import net.pterodactylus.reactor.Reaction;
  28 import net.pterodactylus.reactor.Trigger;
  29 import net.pterodactylus.reactor.states.AbstractState;
  30 import net.pterodactylus.reactor.states.FailedState;
  31 import net.pterodactylus.reactor.states.StateManager;
  32
  33 import org.apache.commons.lang3.tuple.Pair;
  34 import org.apache.log4j.Logger;
  35
  36 import com.google.common.collect.Maps;
  37 import com.google.common.util.concurrent.AbstractExecutionThreadService;
  38
  39 /**
  40  * Reactor main engine.
  41  *
  42  * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
  43  */
  44 public class Engine extends AbstractExecutionThreadService {
  45
  46         /** The logger. */
  47         private static final Logger logger = Logger.getLogger(Engine.class);
  48
  49         /** The state manager. */
  50         private final StateManager stateManager = new StateManager("states");
  51
  52         /** All defined reactions. */
  53         /* synchronize on itself. */
  54         private final Map<String, Reaction> reactions = new HashMap<String, Reaction>();
  55
  56         //
  57         // ACCESSORS
  58         //
  59
  60         /**
  61          * Adds the given reaction to this engine.
  62          *
  63          * @param name
  64          *            The name of the reaction
  65          * @param reaction
  66          *            The reaction to add to this engine
  67          * @throws IllegalStateException
  68          *             if the engine already contains a {@link Reaction} with the
  69          *             given name
  70          */
  71         public void addReaction(String name, Reaction reaction) {
  72                 synchronized (reactions) {
  73                         if (reactions.containsKey(name)) {
  74                                 throw new IllegalStateException(String.format("Engine already contains a Reaction named “%s!”", name));
  75                         }
  76                         reactions.put(name, reaction);
  77                         reactions.notifyAll();
  78                 }
  79         }
  80
  81         /**
  82          * Removes the reaction with the given name.
  83          *
  84          * @param name
  85          *            The name of the reaction to remove
  86          */
  87         public void removeReaction(String name) {
  88                 synchronized (reactions) {
  89                         if (!reactions.containsKey(name)) {
  90                                 return;
  91                         }
  92                         reactions.remove(name);
  93                         reactions.notifyAll();
  94                 }
  95         }
  96
  97         //
  98         // ABSTRACTSERVICE METHODS
  99         //
 100
 101         /**
 102          * {@inheritDoc}
 103          */
 104         @Override
 105         public void run() {
 106                 while (isRunning()) {
 107
 108                         /* delay if we have no reactions. */
 109                         synchronized (reactions) {
 110                                 if (reactions.isEmpty()) {
 111                                         logger.debug("Sleeping while no Reactions available.");
 112                                         try {
 113                                                 reactions.wait();
 114                                         } catch (InterruptedException ie1) {
 115                                                 /* ignore, we’re looping anyway. */
 116                                         }
 117                                         continue;
 118                                 }
 119                         }
 120
 121                         /* find next reaction. */
 122                         SortedMap<Long, Pair<String, Reaction>> nextReactions = Maps.newTreeMap();
 123                         String reactionName;
 124                         Reaction nextReaction;
 125                         synchronized (reactions) {
 126                                 for (Entry<String, Reaction> reactionEntry : reactions.entrySet()) {
 127                                         net.pterodactylus.reactor.State state = stateManager.loadState(reactionEntry.getKey());
 128                                         long stateTime = (state != null) ? state.time() : 0;
 129                                         nextReactions.put(stateTime + reactionEntry.getValue().updateInterval(), Pair.of(reactionEntry.getKey(), reactionEntry.getValue()));
 130                                 }
 131                                 reactionName = nextReactions.get(nextReactions.firstKey()).getLeft();
 132                                 nextReaction = nextReactions.get(nextReactions.firstKey()).getRight();
 133                         }
 134                         logger.debug(String.format("Next Reaction: %s.", nextReaction));
 135
 136                         /* wait until the next reaction has to run. */
 137                         net.pterodactylus.reactor.State lastState = stateManager.loadState(reactionName);
 138                         long lastStateTime = (lastState != null) ? lastState.time() : 0;
 139                         long waitTime = (lastStateTime + nextReaction.updateInterval()) - System.currentTimeMillis();
 140                         logger.debug(String.format("Time to wait for next Reaction: %d millseconds.", waitTime));
 141                         if (waitTime > 0) {
 142                                 synchronized (reactions) {
 143                                         try {
 144                                                 logger.debug(String.format("Waiting for %d milliseconds.", waitTime));
 145                                                 reactions.wait(waitTime);
 146                                         } catch (InterruptedException ie1) {
 147                                                 /* we’re looping! */
 148                                         }
 149                                 }
 150
 151                                 /* re-start loop to check for new reactions. */
 152                                 continue;
 153                         }
 154
 155                         /* run reaction. */
 156                         Query query = nextReaction.query();
 157                         net.pterodactylus.reactor.State state;
 158                         try {
 159                                 logger.debug("Querying system...");
 160                                 state = query.state();
 161                                 if (state == null) {
 162                                         state = FailedState.INSTANCE;
 163                                 }
 164                                 logger.debug("System queried.");
 165                         } catch (Throwable t1) {
 166                                 logger.warn("Querying system failed!", t1);
 167                                 state = new AbstractState(t1) {
 168                                         /* no further state. */
 169                                 };
 170                         }
 171                         logger.debug(String.format("State is %s.", state));
 172
 173                         /* convert states. */
 174                         for (Filter filter : nextReaction.filters()) {
 175                                 if (state.success()) {
 176                                         net.pterodactylus.reactor.State newState = filter.filter(state);
 177                                         logger.debug(String.format("Old state is %s, new state is %s.", state, newState));
 178                                         state = newState;
 179                                 }
 180                         }
 181                         if (state.success()) {
 182                                 stateManager.saveState(reactionName, state);
 183                         }
 184
 185                         /* only run trigger if we have collected two states. */
 186                         Trigger trigger = nextReaction.trigger();
 187                         boolean triggerHit = false;
 188                         if ((lastState != null) && state.success()) {
 189                                 logger.debug("Checking Trigger for changes...");
 190                                 triggerHit = trigger.triggers(state, lastState);
 191                         }
 192
 193                         /* run action if trigger was hit. */
 194                         logger.debug(String.format("Trigger was hit: %s.", triggerHit));
 195                         if (triggerHit) {
 196                                 logger.info("Executing Action...");
 197                                 nextReaction.action().execute(trigger.output());
 198                         }
 199
 200                 }
 201         }
 202
 203 }