/*
* 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.treeinsert;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import opennlp.tools.parser.AbstractContextGenerator;
import opennlp.tools.parser.Cons;
import opennlp.tools.parser.Parse;
/**
* Creates the features or contexts for the building phase of parsing.
* This phase builds constituents from the left-most node of these
* constituents.
*/
public class BuildContextGenerator extends AbstractContextGenerator {
private Parse[] leftNodes;
public BuildContextGenerator() {
super();
leftNodes = new Parse[2];
}
public String[] getContext(Object o) {
Object[] parts = (Object[]) o;
return getContext((Parse[]) parts[0], (Integer) parts[1]);
}
/**
* Returns the contexts/features for the decision to build a new constituent for the specified parse
* at the specified index.
* @param constituents The constituents of the parse so far.
* @param index The index of the constituent where a build decision is being made.
* @return the contexts/features for the decision to build a new constituent.
*/
public String[] getContext(Parse[] constituents, int index) {
Parse p_2 = null;
Parse p_1 = null;
Parse p0 = null;
Parse p1 = null;
Parse p2 = null;
int ps = constituents.length;
p0 = constituents[index];
if (index + 1 < ps) {
p1 = constituents[index + 1];
}
if (index +2 < ps) {
p2 = constituents[index + 2];
}
Collection<Parse> punct1s = null;
Collection<Parse> punct_1s = null;
Collection<Parse> punct2s = null;
Collection<Parse> punct_2s = null;
punct_1s=p0.getPreviousPunctuationSet();
punct1s=p0.getNextPunctuationSet();
if (p1 != null) {
punct2s=p1.getNextPunctuationSet();
}
List<Parse> rf;
if (index == 0) {
rf = Collections.emptyList();
}
else {
//this isn't a root node so, punctSet won't be used and can be passed as empty.
Set<String> emptyPunctSet = Collections.emptySet();
rf = Parser.getRightFrontier(constituents[0], emptyPunctSet);
}
getFrontierNodes(rf,leftNodes);
p_1 = leftNodes[0];
p_2 = leftNodes[1];
if (p_1 != null) {
punct_2s = p_1.getPreviousPunctuationSet();
}
String consp_2 = cons(p_2, -2);
String consp_1 = cons(p_1, -1);
String consp0 = cons(p0, 0);
String consp1 = cons(p1, 1);
String consp2 = cons(p2, 2);
String consbop_2 = consbo(p_2, -2);
String consbop_1 = consbo(p_1, -1);
String consbop0 = consbo(p0, 0);
String consbop1 = consbo(p1, 1);
String consbop2 = consbo(p2, 2);
Cons c_2 = new Cons(consp_2,consbop_2,-2,true);
Cons c_1 = new Cons(consp_1,consbop_1,-1,true);
Cons c0 = new Cons(consp0,consbop0,0,true);
Cons c1 = new Cons(consp1,consbop1,1,true);
Cons c2 = new Cons(consp2,consbop2,2,true);
List<String> features = new ArrayList<String>();
features.add("default");
//unigrams
features.add(consp_2);
features.add(consbop_2);
features.add(consp_1);
features.add(consbop_1);
features.add(consp0);
features.add(consbop0);
features.add(consp1);
features.add(consbop1);
features.add(consp2);
features.add(consbop2);
//cons(0),cons(1)
cons2(features,c0,c1,punct1s,true);
//cons(-1),cons(0)
cons2(features,c_1,c0,punct_1s,true);
//features.add("stage=cons(0),cons(1),cons(2)");
cons3(features,c0,c1,c2,punct1s,punct2s,true,true,true);
cons3(features,c_2,c_1,c0,punct_2s,punct_1s,true,true,true);
cons3(features,c_1,c0,c1,punct_1s,punct_1s,true,true,true);
if (rf.isEmpty()) {
features.add(EOS+","+consp0);
features.add(EOS+","+consbop0);
}
return features.toArray(new String[features.size()]);
}
}