/*
* 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.parser;
import java.util.ArrayList;
import java.util.List;
import opennlp.tools.chunker.ChunkerContextGenerator;
import opennlp.tools.util.Cache;
/**
* Creates predivtive context for the pre-chunking phases of parsing.
*/
public class ChunkContextGenerator implements ChunkerContextGenerator {
private static final String EOS = "eos";
private Cache contextsCache;
private Object wordsKey;
public ChunkContextGenerator() {
this(0);
}
public ChunkContextGenerator(int cacheSize) {
super();
if (cacheSize > 0) {
contextsCache = new Cache(cacheSize);
}
}
public String[] getContext(Object o) {
Object[] data = (Object[]) o;
return getContext(((Integer) data[0]).intValue(), (String[]) data[1], (String[]) data[2], (String[]) data[3]);
}
public String[] getContext(int i, String[] words, String[] prevDecisions, Object[] ac) {
return getContext(i,words,(String[]) ac[0],prevDecisions);
}
public String[] getContext(int i, String[] words, String[] tags, String[] preds) {
List<String> features = new ArrayList<String>(19);
int x0 = i;
int x_2 = x0 - 2;
int x_1 = x0 - 1;
int x2 = x0 + 2;
int x1 = x0 + 1;
String w_2,w_1,w0,w1,w2;
String t_2,t_1,t0,t1,t2;
String p_2,p_1;
// chunkandpostag(-2)
if (x_2 >= 0) {
t_2=tags[x_2];
p_2=preds[x_2];
w_2=words[x_2];
}
else {
t_2=EOS;
p_2=EOS;
w_2=EOS;
}
// chunkandpostag(-1)
if (x_1 >= 0) {
t_1=tags[x_1];
p_1=preds[x_1];
w_1=words[x_1];
}
else {
t_1=EOS;
p_1=EOS;
w_1=EOS;
}
// chunkandpostag(0)
t0=tags[x0];
w0=words[x0];
// chunkandpostag(1)
if (x1 < tags.length) {
t1=tags[x1];
w1=words[x1];
}
else {
t1=EOS;
w1=EOS;
}
// chunkandpostag(2)
if (x2 < tags.length) {
t2=tags[x2];
w2=words[x2];
}
else {
t2=EOS;
w2=EOS;
}
String cacheKey = x0+t_2+t1+t0+t1+t2+p_2+p_1;
if (contextsCache!= null) {
if (wordsKey == words) {
String[] contexts = (String[]) contextsCache.get(cacheKey);
if (contexts != null) {
return contexts;
}
}
else {
contextsCache.clear();
wordsKey = words;
}
}
String ct_2 = chunkandpostag(-2, w_2, t_2, p_2);
String ctbo_2 = chunkandpostagbo(-2, t_2, p_2);
String ct_1 = chunkandpostag(-1, w_1, t_1, p_1);
String ctbo_1 = chunkandpostagbo(-1, t_1, p_1);
String ct0 = chunkandpostag(0, w0, t0, null);
String ctbo0 = chunkandpostagbo(0, t0, null);
String ct1 = chunkandpostag(1, w1, t1, null);
String ctbo1 = chunkandpostagbo(1, t1, null);
String ct2 = chunkandpostag(2, w2, t2, null);
String ctbo2 = chunkandpostagbo(2, t2, null);
features.add("default");
features.add(ct_2);
features.add(ctbo_2);
features.add(ct_1);
features.add(ctbo_1);
features.add(ct0);
features.add(ctbo0);
features.add(ct1);
features.add(ctbo1);
features.add(ct2);
features.add(ctbo2);
//chunkandpostag(-1,0)
features.add(ct_1 + "," + ct0);
features.add(ctbo_1 + "," + ct0);
features.add(ct_1 + "," + ctbo0);
features.add(ctbo_1 + "," + ctbo0);
//chunkandpostag(0,1)
features.add(ct0 + "," + ct1);
features.add(ctbo0 + "," + ct1);
features.add(ct0 + "," + ctbo1);
features.add(ctbo0 + "," + ctbo1);
String contexts[] = features.toArray(new String[features.size()]);
if (contextsCache != null) {
contextsCache.put(cacheKey,contexts);
}
return (contexts);
}
private String chunkandpostag(int i, String tok, String tag, String chunk) {
StringBuilder feat = new StringBuilder(20);
feat.append(i).append("=").append(tok).append("|").append(tag);
if (i < 0) {
feat.append("|").append(chunk);
}
return (feat.toString());
}
private String chunkandpostagbo(int i, String tag, String chunk) {
StringBuilder feat = new StringBuilder(20);
feat.append(i).append("*=").append(tag);
if (i < 0) {
feat.append("|").append(chunk);
}
return (feat.toString());
}
}