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;
  51
  52         /** All defined reactions. */
  53         /* synchronize on itself. */
  54         private final Map<String, Reaction> reactions = new HashMap<String, Reaction>();
  55
  56         /**
  57          * Creates a new engine.
  58          *
  59          * @param stateManager
  60          *            The state manager
  61          */
  62         public Engine(StateManager stateManager) {
  63                 this.stateManager = stateManager;
  64         }
  65
  66         //
  67         // ACCESSORS
  68         //
  69
  70         /**
  71          * Adds the given reaction to this engine.
  72          *
  73          * @param name
  74          *            The name of the reaction
  75          * @param reaction
  76          *            The reaction to add to this engine
  77          */
  78         public void addReaction(String name, Reaction reaction) {
  79                 synchronized (reactions) {
  80                         reactions.put(name, reaction);
  81                         reactions.notifyAll();
  82                 }
  83         }
  84
  85         /**
  86          * Removes the reaction with the given name.
  87          *
  88          * @param name
  89          *            The name of the reaction to remove
  90          */
  91         public void removeReaction(String name) {
  92                 synchronized (reactions) {
  93                         if (!reactions.containsKey(name)) {
  94                                 return;
  95                         }
  96                         reactions.remove(name);
  97                         reactions.notifyAll();
  98                 }
  99         }
 100
 101         //
 102         // ABSTRACTSERVICE METHODS
 103         //
 104
 105         /**
 106          * {@inheritDoc}
 107          */
 108         @Override
 109         public void run() {
 110                 while (isRunning()) {
 111
 112                         /* delay if we have no reactions. */
 113                         synchronized (reactions) {
 114                                 if (reactions.isEmpty()) {
 115                                         logger.debug("Sleeping while no Reactions available.");
 116                                         try {
 117                                                 reactions.wait();
 118                                         } catch (InterruptedException ie1) {
 119                                                 /* ignore, we’re looping anyway. */
 120                                         }
 121                                         continue;
 122                                 }
 123                         }
 124
 125                         /* find next reaction. */
 126                         SortedMap<Long, Pair<String, Reaction>> nextReactions = Maps.newTreeMap();
 127                         String reactionName;
 128                         Reaction nextReaction;
 129                         synchronized (reactions) {
 130                                 for (Entry<String, Reaction> reactionEntry : reactions.entrySet()) {
 131                                         net.pterodactylus.reactor.State state = stateManager.loadLastState(reactionEntry.getKey());
 132                                         long stateTime = (state != null) ? state.time() : 0;
 133                                         nextReactions.put(stateTime + reactionEntry.getValue().updateInterval(), Pair.of(reactionEntry.getKey(), reactionEntry.getValue()));
 134                                 }
 135                                 reactionName = nextReactions.get(nextReactions.firstKey()).getLeft();
 136                                 nextReaction = nextReactions.get(nextReactions.firstKey()).getRight();
 137                         }
 138                         logger.debug(String.format("Next Reaction: %s.", reactionName));
 139
 140                         /* wait until the next reaction has to run. */
 141                         net.pterodactylus.reactor.State lastState = stateManager.loadLastState(reactionName);
 142                         long lastStateTime = (lastState != null) ? lastState.time() : 0;
 143                         int lastStateFailCount = (lastState != null) ? lastState.failCount() : 0;
 144                         long waitTime = (lastStateTime + nextReaction.updateInterval()) - System.currentTimeMillis();
 145                         logger.debug(String.format("Time to wait for next Reaction: %d millseconds.", waitTime));
 146                         if (waitTime > 0) {
 147                                 synchronized (reactions) {
 148                                         try {
 149                                                 logger.info(String.format("Waiting until %tc.", lastStateTime + nextReaction.updateInterval()));
 150                                                 reactions.wait(waitTime);
 151                                         } catch (InterruptedException ie1) {
 152                                                 /* we’re looping! */
 153                                         }
 154                                 }
 155
 156                                 /* re-start loop to check for new reactions. */
 157                                 continue;
 158                         }
 159
 160                         /* run reaction. */
 161                         logger.info(String.format("Running Query for %s...", reactionName));
 162                         Query query = nextReaction.query();
 163                         net.pterodactylus.reactor.State state;
 164                         try {
 165                                 logger.debug("Querying system...");
 166                                 state = query.state();
 167                                 if (state == null) {
 168                                         state = FailedState.INSTANCE;
 169                                 }
 170                                 logger.debug("System queried.");
 171                         } catch (Throwable t1) {
 172                                 logger.warn("Querying system failed!", t1);
 173                                 state = new AbstractState(t1) {
 174                                         /* no further state. */
 175                                 };
 176                         }
 177                         logger.debug(String.format("State is %s.", state));
 178
 179                         /* convert states. */
 180                         for (Filter filter : nextReaction.filters()) {
 181                                 if (state.success()) {
 182                                         net.pterodactylus.reactor.State newState = filter.filter(state);
 183                                         logger.debug(String.format("Old state is %s, new state is %s.", state, newState));
 184                                         state = newState;
 185                                 }
 186                         }
 187                         if (!state.success()) {
 188                                 state.setFailCount(lastStateFailCount + 1);
 189                         }
 190                         net.pterodactylus.reactor.State lastSuccessfulState = stateManager.loadLastSuccessfulState(reactionName);
 191                         stateManager.saveState(reactionName, state);
 192
 193                         /* only run trigger if we have collected two successful states. */
 194                         Trigger trigger = nextReaction.trigger();
 195                         boolean triggerHit = false;
 196                         if ((lastSuccessfulState != null) && lastSuccessfulState.success() && state.success()) {
 197                                 logger.debug("Checking Trigger for changes...");
 198                                 triggerHit = trigger.triggers(state, lastSuccessfulState);
 199                         }
 200
 201                         /* run action if trigger was hit. */
 202                         logger.debug(String.format("Trigger was hit: %s.", triggerHit));
 203                         if (triggerHit) {
 204                                 logger.info("Executing Action...");
 205                                 nextReaction.action().execute(trigger.output(nextReaction));
 206                         }
 207
 208                 }
 209         }
 210
 211 }