/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package opennlp.tools.coref.resolver;
import java.io.DataInputStream;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import opennlp.maxent.GIS;
import opennlp.maxent.io.BinaryGISModelReader;
import opennlp.maxent.io.SuffixSensitiveGISModelReader;
import opennlp.maxent.io.SuffixSensitiveGISModelWriter;
import opennlp.model.Event;
import opennlp.model.MaxentModel;
import opennlp.tools.coref.mention.MentionContext;
import opennlp.tools.coref.mention.Parse;
import opennlp.tools.util.CollectionEventStream;
/**
* Default implementation of the {@link NonReferentialResolver} interface.
*/
public class DefaultNonReferentialResolver implements NonReferentialResolver {
private MaxentModel model;
private List<Event> events;
private boolean loadAsResource;
private boolean debugOn = false;
private ResolverMode mode;
private String modelName;
private String modelExtension = ".bin.gz";
private int nonRefIndex;
public DefaultNonReferentialResolver(String projectName, String name, ResolverMode mode) throws IOException {
this.mode = mode;
this.modelName = projectName+"/"+name+".nr";
if (mode == ResolverMode.TRAIN) {
events = new ArrayList<Event>();
}
else if (mode == ResolverMode.TEST) {
if (loadAsResource) {
model = (new BinaryGISModelReader(new DataInputStream(this.getClass().getResourceAsStream(modelName)))).getModel();
}
else {
model = (new SuffixSensitiveGISModelReader(new File(modelName+modelExtension))).getModel();
}
nonRefIndex = model.getIndex(MaxentResolver.SAME);
}
else {
throw new RuntimeException("unexpected mode "+mode);
}
}
public double getNonReferentialProbability(MentionContext mention) {
List<String> features = getFeatures(mention);
double r = model.eval(features.toArray(new String[features.size()]))[nonRefIndex];
if (debugOn) System.err.println(this +" " + mention.toText() + " -> null " + r + " " + features);
return r;
}
public void addEvent(MentionContext ec) {
List<String> features = getFeatures(ec);
if (-1 == ec.getId()) {
events.add(new Event(MaxentResolver.SAME, features.toArray(new String[features.size()])));
}
else {
events.add(new Event(MaxentResolver.DIFF, features.toArray(new String[features.size()])));
}
}
protected List<String> getFeatures(MentionContext mention) {
List<String> features = new ArrayList<String>();
features.add(MaxentResolver.DEFAULT);
features.addAll(getNonReferentialFeatures(mention));
return features;
}
/**
* Returns a list of features used to predict whether the specified mention is non-referential.
* @param mention The mention under consideration.
* @return a list of features used to predict whether the specified mention is non-referential.
*/
protected List<String> getNonReferentialFeatures(MentionContext mention) {
List<String> features = new ArrayList<String>();
Parse[] mtokens = mention.getTokenParses();
//System.err.println("getNonReferentialFeatures: mention has "+mtokens.length+" tokens");
for (int ti = 0; ti <= mention.getHeadTokenIndex(); ti++) {
Parse tok = mtokens[ti];
List<String> wfs = ResolverUtils.getWordFeatures(tok);
for (int wfi = 0; wfi < wfs.size(); wfi++) {
features.add("nr" + wfs.get(wfi));
}
}
features.addAll(ResolverUtils.getContextFeatures(mention));
return features;
}
public void train() throws IOException {
if (ResolverMode.TRAIN == mode) {
System.err.println(this +" referential");
if (debugOn) {
FileWriter writer = new FileWriter(modelName+".events");
for (Iterator<Event> ei=events.iterator();ei.hasNext();) {
Event e = ei.next();
writer.write(e.toString()+"\n");
}
writer.close();
}
(new SuffixSensitiveGISModelWriter(GIS.trainModel(new CollectionEventStream(events),100,10),new File(modelName+modelExtension))).persist();
}
}
}