package org.maltparserx.parser.algorithm.nivre;
import java.util.Stack;
import org.maltparserx.core.exception.MaltChainedException;
import org.maltparserx.core.syntaxgraph.edge.Edge;
import org.maltparserx.core.syntaxgraph.node.DependencyNode;
import org.maltparserx.parser.ParserConfiguration;
import org.maltparserx.parser.TransitionSystem;
import org.maltparserx.parser.history.GuideUserHistory;
import org.maltparserx.parser.history.History;
import org.maltparserx.parser.history.action.ComplexDecisionAction;
import org.maltparserx.parser.history.action.GuideUserAction;
import org.maltparserx.parser.transition.TransitionTable;
/**
* @author Johan Hall
*
*/
public class ArcEager extends TransitionSystem {
protected static final int SHIFT = 1;
protected static final int REDUCE = 2;
protected static final int RIGHTARC = 3;
protected static final int LEFTARC = 4;
public ArcEager() throws MaltChainedException {
super();
}
public void apply(GuideUserAction currentAction, ParserConfiguration config) throws MaltChainedException {
final NivreConfig nivreConfig = (NivreConfig)config;
final Stack<DependencyNode> stack = nivreConfig.getStack();
final Stack<DependencyNode> input = nivreConfig.getInput();
currentAction.getAction(actionContainers);
Edge e = null;
switch (transActionContainer.getActionCode()) {
case LEFTARC:
e = nivreConfig.getDependencyStructure().addDependencyEdge(input.peek().getIndex(), stack.peek().getIndex());
addEdgeLabels(e);
stack.pop();
// doPropagation(e);
break;
case RIGHTARC:
e = nivreConfig.getDependencyStructure().addDependencyEdge(stack.peek().getIndex(), input.peek().getIndex());
addEdgeLabels(e);
stack.push(input.pop());
// doPropagation(e);
break;
case REDUCE:
stack.pop();
break;
default:
stack.push(input.pop());
break;
}
}
public GuideUserAction getDeterministicAction(GuideUserHistory history, ParserConfiguration config) throws MaltChainedException {
final NivreConfig nivreConfig = (NivreConfig)config;
if (!nivreConfig.isAllowRoot() && nivreConfig.getStack().peek().isRoot()) {
return updateActionContainers(history, ArcEager.SHIFT, null);
}
return null;
}
protected void addAvailableTransitionToTable(TransitionTable ttable) throws MaltChainedException {
ttable.addTransition(SHIFT, "SH", false, null);
ttable.addTransition(REDUCE, "RE", false, null);
ttable.addTransition(RIGHTARC, "RA", true, null);
ttable.addTransition(LEFTARC, "LA", true, null);
}
protected void initWithDefaultTransitions(GuideUserHistory history) throws MaltChainedException {
GuideUserAction currentAction = new ComplexDecisionAction((History)history);
transActionContainer.setAction(SHIFT);
transActionContainer.setAction(REDUCE);
for (int i = 0; i < arcLabelActionContainers.length; i++) {
arcLabelActionContainers[i].setAction(-1);
}
currentAction.addAction(actionContainers);
}
public String getName() {
return "nivreeager";
}
public boolean permissible(GuideUserAction currentAction, ParserConfiguration config) throws MaltChainedException {
currentAction.getAction(actionContainers);
final int trans = transActionContainer.getActionCode();
final DependencyNode stackPeek = ((NivreConfig)config).getStack().peek();
if ((trans == LEFTARC || trans == RIGHTARC) && !isActionContainersLabeled()) {
return false;
}
if ((trans == LEFTARC || trans == REDUCE) && stackPeek.isRoot()) {
return false;
}
if (trans == LEFTARC && stackPeek.hasHead()) {
return false;
}
if (trans == REDUCE && !stackPeek.hasHead() && !((NivreConfig)config).isAllowReduce()) {
return false;
}
return true;
}
public GuideUserAction defaultAction(GuideUserHistory history, ParserConfiguration configuration) throws MaltChainedException {
return updateActionContainers(history, ArcEager.SHIFT, null);
}
}