| 1 | package dk.deepthought.sidious.goalhandler; |
| 2 | |
| 3 | import java.util.PriorityQueue; |
| 4 | |
| 5 | import org.apache.commons.logging.Log; |
| 6 | import org.apache.commons.logging.LogFactory; |
| 7 | |
| 8 | import dk.deepthought.sidious.ruleengine.RuleEngine; |
| 9 | import dk.deepthought.sidious.supportsystem.Repository; |
| 10 | import dk.deepthought.sidious.supportsystem.SuperLinkID; |
| 11 | import dk.deepthought.sidious.supportsystem.SystemSettings; |
| 12 | import dk.deepthought.sidious.util.SidiousQueue; |
| 13 | |
| 14 | /** |
| 15 | * This class prioritizes goals and chooses which are to be sent to the |
| 16 | * <code>BlackBoard</code>. |
| 17 | * <p> |
| 18 | * The class extends the sidious queue and process goals asynchronously. |
| 19 | * |
| 20 | * @author Deepthought |
| 21 | * |
| 22 | */ |
| 23 | public class GoalHandlerEngine extends SidiousQueue<SuperLinkID> implements |
| 24 | GoalHandler { |
| 25 | /** |
| 26 | * Logger for this class |
| 27 | */ |
| 28 | private static final Log logger = LogFactory |
| 29 | .getLog(GoalHandlerEngine.class); |
| 30 | |
| 31 | /** |
| 32 | * Private Singleton instance. |
| 33 | */ |
| 34 | private static final GoalHandler INSTANCE = new GoalHandlerEngine(); |
| 35 | |
| 36 | /** |
| 37 | * Private constructor to facilitate singleton property. |
| 38 | */ |
| 39 | private GoalHandlerEngine() { |
| 40 | super(GoalHandlerEngine.class.getSimpleName()); |
| 41 | } |
| 42 | |
| 43 | /* |
| 44 | * (non-Javadoc) |
| 45 | * |
| 46 | * @see dk.deepthought.sidious.goalhandler.GoalHandler#getTopPriorityGoal(dk.deepthought.sidious.supportsystem.SuperLinkID) |
| 47 | */ |
| 48 | public Goal getTopPriorityGoal(SuperLinkID id) { |
| 49 | if (logger.isDebugEnabled()) { |
| 50 | logger.debug("getTopPriorityGoal(SuperLinkID id=" + id |
| 51 | + ") - start"); |
| 52 | } |
| 53 | RuleEngine ruleEngine = Repository.getRuleEngine(); |
| 54 | PriorityQueue<Goal> queue = new PriorityQueue<Goal>(ruleEngine |
| 55 | .extractGoals(id)); |
| 56 | if (queue == null) { |
| 57 | if (logger.isDebugEnabled()) { |
| 58 | logger.debug("getTopPriorityGoal(SuperLinkID id=" + id |
| 59 | + ") - end - return value=null"); |
| 60 | } |
| 61 | return null; |
| 62 | } |
| 63 | Goal returnGoal = queue.peek(); |
| 64 | if (logger.isDebugEnabled()) { |
| 65 | logger.debug("getTopPriorityGoal(SuperLinkID id=" + id |
| 66 | + ") - end - return value=" + returnGoal); |
| 67 | } |
| 68 | return returnGoal; |
| 69 | } |
| 70 | |
| 71 | /** |
| 72 | * Returns the singleton instance of this goal handler. |
| 73 | * |
| 74 | * @return the singleton instance |
| 75 | */ |
| 76 | public static GoalHandler getInstance() { |
| 77 | return INSTANCE; |
| 78 | } |
| 79 | |
| 80 | /* |
| 81 | * (non-Javadoc) |
| 82 | * |
| 83 | * @see dk.deepthought.sidious.goalhandler.GoalHandler#request(dk.deepthought.sidious.supportsystem.SuperLinkID) |
| 84 | */ |
| 85 | public final void request(SuperLinkID id) { |
| 86 | enqueue(id); |
| 87 | } |
| 88 | |
| 89 | /* |
| 90 | * (non-Javadoc) |
| 91 | * |
| 92 | * @see dk.deepthought.sidious.util.SidiousQueue#process(java.lang.Object) |
| 93 | */ |
| 94 | @Override |
| 95 | protected void process(SuperLinkID item) { |
| 96 | Goal goal = getTopPriorityGoal(item); |
| 97 | if (goal != null && !SystemSettings.isTestMode()) { |
| 98 | Repository.getBlackboard().deliverResult(goal); |
| 99 | } |
| 100 | } |
| 101 | |
| 102 | } |