package edu.stanford.nlp.trees;
import edu.stanford.nlp.ling.Label;
import edu.stanford.nlp.ling.LabelFactory;
/**
* A <code>SimpleConstituent</code> object defines a generic edge in a graph.
* The <code>SimpleConstituent</code> records only the endpoints of the
* <code>Constituent</code>, as two integers.
* It doesn't label the edges.
* (It doesn't implement equals() since this actually decreases
* performance on a non-final class (requires dynamic resolution of which
* to call).)
*
* @author Christopher Manning
*/
public class SimpleConstituent extends Constituent {
/**
* Left node of edge.
*/
private int start;
/**
* End node of edge.
*/
private int end;
/**
* Create an empty <code>SimpleConstituent</code> object.
*/
public SimpleConstituent() {
// implicitly super();
}
/**
* Create a <code>SimpleConstituent</code> object with given values.
*
* @param start start node of edge
* @param end end node of edge
*/
public SimpleConstituent(int start, int end) {
this.start = start;
this.end = end;
}
/**
* access start node.
*/
@Override
public int start() {
return start;
}
/**
* set start node.
*/
@Override
public void setStart(int start) {
this.start = start;
}
/**
* access end node.
*/
@Override
public int end() {
return end;
}
/**
* set end node.
*/
@Override
public void setEnd(int end) {
this.end = end;
}
/**
* A <code>SimpleConstituentLabelFactory</code> object makes a
* <code>StringLabel</code> <code>LabeledScoredConstituent</code>.
*/
private static class SimpleConstituentLabelFactory implements LabelFactory {
/**
* Make a new <code>SimpleConstituent</code>.
*
* @param labelStr A string.
* @return The created label
*/
public Label newLabel(final String labelStr) {
return new SimpleConstituent(0, 0);
}
/**
* Make a new <code>SimpleConstituent</code>.
*
* @param labelStr A string.
* @param options The options are ignored.
* @return The created label
*/
public Label newLabel(final String labelStr, final int options) {
return newLabel(labelStr);
}
/**
* Make a new <code>SimpleConstituent</code>.
*
* @param labelStr A string.
* @return The created label
*/
public Label newLabelFromString(final String labelStr) {
return newLabel(labelStr);
}
/**
* Create a new <code>SimpleConstituent</code>.
*
* @param oldLabel A <code>Label</code>.
* @return A new <code>SimpleConstituent</code>
*/
public Label newLabel(Label oldLabel) {
return new SimpleConstituent(0, 0);
}
}
// extra class guarantees correct lazy loading (Bloch p.194)
private static class LabelFactoryHolder {
static final LabelFactory lf = new SimpleConstituentLabelFactory();
}
/**
* Return a factory for this kind of label.
* The factory returned is always the same one (a singleton)
*
* @return the label factory
*/
public LabelFactory labelFactory() {
return LabelFactoryHolder.lf;
}
// extra class guarantees correct lazy loading (Bloch p.194)
private static class ConstituentFactoryHolder {
/**
* A <code>SimpleConstituentFactory</code> acts as a factory for
* creating objects of class <code>SimpleConstituent</code>.
*/
private static class SimpleConstituentFactory implements ConstituentFactory {
public Constituent newConstituent(int start, int end) {
return new SimpleConstituent(start, end);
}
public Constituent newConstituent(int start, int end, Label label, double score) {
return new SimpleConstituent(start, end);
}
}
static final ConstituentFactory cf = new SimpleConstituentFactory();
}
/**
* Return a factory for this kind of constituent.
* The factory returned is always the same one (a singleton).
*
* @return The constituent factory
*/
public ConstituentFactory constituentFactory() {
return ConstituentFactoryHolder.cf;
}
/**
* Return a factory for this kind of constituent.
* The factory returned is always the same one (a singleton).
*
* @return The constituent factory
*/
public static ConstituentFactory factory() {
return ConstituentFactoryHolder.cf;
}
}
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