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Stanford Parser processes raw text in English, Chinese, German, Arabic, and French, and extracts constituency parse trees.
package edu.stanford.nlp.util;
import java.util.*;
/**
* Implements a finite beam, taking a comparator (default is
* ScoredComparator.ASCENDING_COMPARATOR, the MAX object according to
* the comparator is the one to be removed) and a beam size on
* construction (default is 100). Adding an object may cause the
* worst-scored object to be removed from the beam (and that object
* may well be the newly added object itself).
*
* @author Dan Klein
* @version 1.0
*/
public class Beam extends AbstractSet {
protected final int maxBeamSize;
protected final Heap elements;
public int capacity() {
return maxBeamSize;
}
@Override
public int size() {
return elements.size();
}
@Override
public Iterator iterator() {
return asSortedList().iterator();
}
public List asSortedList() {
LinkedList list = new LinkedList<>();
for (Iterator i = elements.iterator(); i.hasNext();) {
list.addFirst(i.next());
}
return list;
}
@Override
public boolean add(T o) {
boolean added = true;
elements.add(o);
while (size() > capacity()) {
Object dumped = elements.extractMin();
if (dumped.equals(o)) {
added = false;
}
}
return added;
}
@Override
public boolean remove(Object o) {
//return elements.remove(o);
throw new UnsupportedOperationException();
}
public Beam() {
this(100);
}
// TODO dlwh: This strikes me as unsafe even now.
public Beam(int maxBeamSize) {
this(maxBeamSize, ErasureUtils.>uncheckedCast(ScoredComparator.ASCENDING_COMPARATOR));
}
public Beam(int maxBeamSize, Comparator cmp) {
elements = new ArrayHeap<>(cmp);
this.maxBeamSize = maxBeamSize;
}
/*
* This is a test
public static void main(String[] args) {
Beam b = new Beam(2, ScoredComparator.ASCENDING_COMPARATOR);
b.add(new ScoredObject("1", 1.0));
b.add(new ScoredObject("2", 2.0));
b.add(new ScoredObject("3", 3.0));
b.add(new ScoredObject("0", 0.0));
for (Iterator bI = b.iterator(); bI.hasNext();) {
ScoredObject sO = bI.next();
System.out.println(sO);
}
}
*/
}