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