/*
* 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.formats.muc;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Stack;
import opennlp.tools.tokenize.Tokenizer;
import opennlp.tools.util.Span;
// Note:
// Take care for special @ sign handling (identifies a table or something else that should be ignored)
class MucCorefContentHandler extends SgmlParser.ContentHandler {
static class CorefMention {
Span span;
int id;
String min;
CorefMention(Span span, int id, String min) {
this.span = span;
this.id = id;
this.min = min;
}
}
static final String COREF_ELEMENT = "COREF";
private final Tokenizer tokenizer;
private final List<RawCorefSample> samples;
boolean isInsideContentElement = false;
private final List<String> text = new ArrayList<String>();
private Stack<CorefMention> mentionStack = new Stack<CorefMention>();
private List<CorefMention> mentions = new ArrayList<MucCorefContentHandler.CorefMention>();
private Map<Integer, Integer> idMap = new HashMap<Integer, Integer>();
private RawCorefSample sample;
MucCorefContentHandler(Tokenizer tokenizer, List<RawCorefSample> samples) {
this.tokenizer = tokenizer;
this.samples = samples;
}
/**
* Resolve an id via the references to the root id.
*
* @param id the id or reference to be resolved
*
* @return the resolved id or -1 if id cannot be resolved
*/
private int resolveId(int id) {
Integer refId = idMap.get(id);
if (refId != null) {
if (id == refId) {
return id;
}
else {
return resolveId(refId);
}
}
else {
return -1;
}
}
@Override
public void startElement(String name, Map<String, String> attributes) {
if (MucElementNames.DOC_ELEMENT.equals(name)) {
idMap.clear();
sample = new RawCorefSample(new ArrayList<String>(),
new ArrayList<MucCorefContentHandler.CorefMention[]>());
}
if (MucElementNames.CONTENT_ELEMENTS.contains(name)) {
isInsideContentElement = true;
}
if (COREF_ELEMENT.equals(name)) {
int beginOffset = text.size();
String idString = attributes.get("ID");
String refString = attributes.get("REF");
int id;
if (idString != null) {
id = Integer.parseInt(idString); // might fail
if (refString == null) {
idMap.put(id, id);
}
else {
int ref = Integer.parseInt(refString);
idMap.put(id, ref);
}
}
else {
id = -1;
// throw invalid format exception ...
}
mentionStack.push(new CorefMention(new Span(beginOffset, beginOffset), id, attributes.get("MIN")));
}
}
@Override
public void characters(CharSequence chars) {
if (isInsideContentElement) {
String tokens [] = tokenizer.tokenize(chars.toString());
text.addAll(Arrays.asList(tokens));
}
}
@Override
public void endElement(String name) {
if (COREF_ELEMENT.equals(name)) {
CorefMention mention = mentionStack.pop();
mention.span = new Span(mention.span.getStart(), text.size());
mentions.add(mention);
}
if (MucElementNames.CONTENT_ELEMENTS.contains(name)) {
sample.getTexts().add(text.toArray(new String[text.size()]));
sample.getMentions().add(mentions.toArray(new CorefMention[mentions.size()]));
mentions.clear();
text.clear();
isInsideContentElement = false;
}
if (MucElementNames.DOC_ELEMENT.equals(name)) {
for (CorefMention mentions[] : sample.getMentions()) {
for (int i = 0; i < mentions.length; i++) {
mentions[i].id = resolveId(mentions[i].id);
}
}
samples.add(sample);
}
}
}