001    package org.maltparser.parser.algorithm.covington;
002    
003    import org.maltparser.core.exception.MaltChainedException;
004    import org.maltparser.core.syntaxgraph.DependencyStructure;
005    import org.maltparser.core.syntaxgraph.node.DependencyNode;
006    import org.maltparser.parser.DependencyParserConfig;
007    import org.maltparser.parser.Oracle;
008    import org.maltparser.parser.ParserConfiguration;
009    import org.maltparser.parser.history.GuideUserHistory;
010    import org.maltparser.parser.history.action.GuideUserAction;
011    /**
012     * @author Johan Hall
013     *
014     */
015    public class CovingtonOracle extends Oracle {
016            public CovingtonOracle(DependencyParserConfig manager, GuideUserHistory history) throws MaltChainedException {
017                    super(manager, history);
018                    setGuideName("NonProjective");
019            }
020            
021            public GuideUserAction predict(DependencyStructure gold, ParserConfiguration config) throws MaltChainedException {
022                    CovingtonConfig covingtonConfig = (CovingtonConfig)config;
023                    DependencyNode leftTarget = covingtonConfig.getLeftTarget();
024                    int leftTargetIndex = leftTarget.getIndex();
025                    int rightTargetIndex = covingtonConfig.getRightTarget().getIndex();
026                    
027                    if (!leftTarget.isRoot() && gold.getTokenNode(leftTargetIndex).getHead().getIndex() == rightTargetIndex) {
028                            return updateActionContainers(NonProjective.LEFTARC, gold.getTokenNode(leftTargetIndex).getHeadEdge().getLabelSet());
029                    } else if (gold.getTokenNode(rightTargetIndex).getHead().getIndex() == leftTargetIndex) {
030                            return updateActionContainers(NonProjective.RIGHTARC, gold.getTokenNode(rightTargetIndex).getHeadEdge().getLabelSet());
031                    } else if (covingtonConfig.isAllowShift() == true && (!(gold.getTokenNode(rightTargetIndex).hasLeftDependent() 
032                                    && gold.getTokenNode(rightTargetIndex).getLeftmostDependent().getIndex() < leftTargetIndex)
033                                    && !(gold.getTokenNode(rightTargetIndex).getHead().getIndex() < leftTargetIndex 
034                                                    && (!gold.getTokenNode(rightTargetIndex).getHead().isRoot() || covingtonConfig.getLeftstop() == 0)))) {
035                            return updateActionContainers(NonProjective.SHIFT, null);
036                    } else {
037                            return updateActionContainers(NonProjective.NOARC, null);
038                    }
039            }
040            
041            public void finalizeSentence(DependencyStructure dependencyGraph) throws MaltChainedException {
042                    
043            }
044            
045            public void terminate() throws MaltChainedException {
046                    
047            }
048    }