| /* |
| * 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 org.apache.lucene.classification.utils; |
| |
| import java.io.IOException; |
| |
| import org.apache.lucene.index.Terms; |
| import org.apache.lucene.index.TermsEnum; |
| import org.apache.lucene.util.BytesRef; |
| |
| /** |
| * utility class for converting Lucene {@link org.apache.lucene.document.Document}s to <code>Double</code> vectors. |
| */ |
| public class DocToDoubleVectorUtils { |
| |
| private DocToDoubleVectorUtils() { |
| // no public constructors |
| } |
| |
| /** |
| * create a sparse <code>Double</code> vector given doc and field term vectors using local frequency of the terms in the doc |
| * |
| * @param docTerms term vectors for a given document |
| * @param fieldTerms field term vectors |
| * @return a sparse vector of <code>Double</code>s as an array |
| * @throws IOException in case accessing the underlying index fails |
| */ |
| public static Double[] toSparseLocalFreqDoubleArray(Terms docTerms, Terms fieldTerms) throws IOException { |
| TermsEnum fieldTermsEnum = fieldTerms.iterator(); |
| Double[] freqVector = null; |
| if (docTerms != null && fieldTerms.size() > -1) { |
| freqVector = new Double[(int) fieldTerms.size()]; |
| int i = 0; |
| TermsEnum docTermsEnum = docTerms.iterator(); |
| BytesRef term; |
| while ((term = fieldTermsEnum.next()) != null) { |
| TermsEnum.SeekStatus seekStatus = docTermsEnum.seekCeil(term); |
| if (seekStatus.equals(TermsEnum.SeekStatus.END)) { |
| docTermsEnum = docTerms.iterator(); |
| } |
| if (seekStatus.equals(TermsEnum.SeekStatus.FOUND)) { |
| long termFreqLocal = docTermsEnum.totalTermFreq(); // the total number of occurrences of this term in the given document |
| freqVector[i] = Long.valueOf(termFreqLocal).doubleValue(); |
| } else { |
| freqVector[i] = 0d; |
| } |
| i++; |
| } |
| } |
| return freqVector; |
| } |
| |
| /** |
| * create a dense <code>Double</code> vector given doc and field term vectors using local frequency of the terms in the doc |
| * |
| * @param docTerms term vectors for a given document |
| * @return a dense vector of <code>Double</code>s as an array |
| * @throws IOException in case accessing the underlying index fails |
| */ |
| public static Double[] toDenseLocalFreqDoubleArray(Terms docTerms) throws IOException { |
| Double[] freqVector = null; |
| if (docTerms != null) { |
| freqVector = new Double[(int) docTerms.size()]; |
| int i = 0; |
| TermsEnum docTermsEnum = docTerms.iterator(); |
| |
| while (docTermsEnum.next() != null) { |
| long termFreqLocal = docTermsEnum.totalTermFreq(); // the total number of occurrences of this term in the given document |
| freqVector[i] = Long.valueOf(termFreqLocal).doubleValue(); |
| i++; |
| } |
| } |
| return freqVector; |
| } |
| } |