package org.maltparserx.parser.algorithm.stack;
import java.util.Stack;
import org.maltparserx.core.exception.MaltChainedException;
import org.maltparserx.core.syntaxgraph.LabelSet;
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 Projective extends TransitionSystem {
protected static final int SHIFT = 1;
protected static final int RIGHTARC = 2;
protected static final int LEFTARC = 3;
public Projective() throws MaltChainedException {
super();
}
public void apply(GuideUserAction currentAction, ParserConfiguration configuration) throws MaltChainedException {
final StackConfig config = (StackConfig)configuration;
final Stack<DependencyNode> stack = config.getStack();
currentAction.getAction(actionContainers);
Edge e = null;
DependencyNode head = null;
DependencyNode dep = null;
switch (transActionContainer.getActionCode()) {
case LEFTARC:
head = stack.pop();
dep = stack.pop();
e = config.getDependencyStructure().addDependencyEdge(head.getIndex(), dep.getIndex());
addEdgeLabels(e);
stack.push(head);
break;
case RIGHTARC:
dep = stack.pop();
e = config.getDependencyStructure().addDependencyEdge(stack.peek().getIndex(), dep.getIndex());
addEdgeLabels(e);
break;
default:
final Stack<DependencyNode> input = config.getInput();
if (input.isEmpty()) {
stack.pop();
} else {
stack.push(input.pop()); // SHIFT
}
break;
}
}
public boolean permissible(GuideUserAction currentAction, ParserConfiguration configuration) throws MaltChainedException {
final StackConfig config = (StackConfig)configuration;
currentAction.getAction(actionContainers);
final int trans = transActionContainer.getActionCode();
if ((trans == LEFTARC || trans == RIGHTARC) && !isActionContainersLabeled()) {
return false;
}
final Stack<DependencyNode> stack = config.getStack();
if ((trans == LEFTARC || trans == RIGHTARC) && stack.size() < 2) {
return false;
}
if (trans == LEFTARC && stack.get(stack.size()-2).isRoot()) {
return false;
}
if (trans == SHIFT && config.getInput().isEmpty()) {
return false;
}
return true;
}
public GuideUserAction getDeterministicAction(GuideUserHistory history, ParserConfiguration config) throws MaltChainedException {
return null;
}
protected void addAvailableTransitionToTable(TransitionTable ttable) throws MaltChainedException {
ttable.addTransition(SHIFT, "SH", 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);
for (int i = 0; i < arcLabelActionContainers.length; i++) {
arcLabelActionContainers[i].setAction(-1);
}
currentAction.addAction(actionContainers);
}
public String getName() {
return "projective";
}
public GuideUserAction defaultAction(GuideUserHistory history, ParserConfiguration configuration) throws MaltChainedException {
if (((StackConfig)configuration).getInput().isEmpty()) {
LabelSet labelSet = ((StackConfig)configuration).getDependencyGraph().getDefaultRootEdgeLabels();
return updateActionContainers(history, RIGHTARC, labelSet);
}
return updateActionContainers(history, SHIFT, null);
}
}