package org.apache.lucene.search.suggest;
/*
* 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.
*/
import java.io.IOException;
import java.util.Comparator;
import java.util.HashSet;
import java.util.Set;
import org.apache.lucene.document.Document;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.IndexableField;
import org.apache.lucene.index.MultiDocValues;
import org.apache.lucene.index.MultiFields;
import org.apache.lucene.index.NumericDocValues;
import org.apache.lucene.search.spell.Dictionary;
import org.apache.lucene.util.Bits;
import org.apache.lucene.util.BytesRef;
import org.apache.lucene.util.BytesRefIterator;
/**
* <p>
* Dictionary with terms, weights and optionally payload information
* taken from stored/indexed fields in a Lucene index.
* </p>
* <b>NOTE:</b>
* <ul>
* <li>
* The term and (optionally) payload fields have to be
* stored
* </li>
* <li>
* The weight field can be stored or can be a {@link NumericDocValues}.
* If the weight field is not defined, the value of the weight is <code>0</code>
* </li>
* <li>
* if any of the term or (optionally) payload fields supplied
* do not have a value for a document, then the document is
* skipped by the dictionary
* </li>
* </ul>
*/
public class DocumentDictionary implements Dictionary {
/** {@link IndexReader} to load documents from */
protected final IndexReader reader;
/** Field to read payload from */
protected final String payloadField;
private final String field;
private final String weightField;
/**
* Creates a new dictionary with the contents of the fields named <code>field</code>
* for the terms and <code>weightField</code> for the weights that will be used for
* the corresponding terms.
*/
public DocumentDictionary(IndexReader reader, String field, String weightField) {
this(reader, field, weightField, null);
}
/**
* Creates a new dictionary with the contents of the fields named <code>field</code>
* for the terms, <code>weightField</code> for the weights that will be used for the
* the corresponding terms and <code>payloadField</code> for the corresponding payloads
* for the entry.
*/
public DocumentDictionary(IndexReader reader, String field, String weightField, String payloadField) {
this.reader = reader;
this.field = field;
this.weightField = weightField;
this.payloadField = payloadField;
}
@Override
public InputIterator getEntryIterator() throws IOException {
return new DocumentInputIterator(payloadField!=null);
}
/** Implements {@link InputIterator} from stored fields. */
protected class DocumentInputIterator implements InputIterator {
private final int docCount;
private final Set<String> relevantFields;
private final boolean hasPayloads;
private final Bits liveDocs;
private int currentDocId = -1;
private long currentWeight;
private BytesRef currentPayload;
private final NumericDocValues weightValues;
/**
* Creates an iterator over term, weight and payload fields from the lucene
* index. setting <code>withPayload</code> to false, implies an iterator
* over only term and weight.
*/
public DocumentInputIterator(boolean hasPayloads) throws IOException {
this.hasPayloads = hasPayloads;
docCount = reader.maxDoc() - 1;
weightValues = (weightField != null) ? MultiDocValues.getNumericValues(reader, weightField) : null;
liveDocs = (reader.leaves().size() > 0) ? MultiFields.getLiveDocs(reader) : null;
relevantFields = getRelevantFields(new String [] {field, weightField, payloadField});
}
@Override
public long weight() {
return currentWeight;
}
@Override
public Comparator<BytesRef> getComparator() {
return null;
}
@Override
public BytesRef next() throws IOException {
while (currentDocId < docCount) {
currentDocId++;
if (liveDocs != null && !liveDocs.get(currentDocId)) {
continue;
}
Document doc = reader.document(currentDocId, relevantFields);
BytesRef tempPayload = null;
BytesRef tempTerm = null;
if (hasPayloads) {
IndexableField payload = doc.getField(payloadField);
if (payload == null || (payload.binaryValue() == null && payload.stringValue() == null)) {
continue;
}
tempPayload = (payload.binaryValue() != null) ? payload.binaryValue() : new BytesRef(payload.stringValue());
}
IndexableField fieldVal = doc.getField(field);
if (fieldVal == null || (fieldVal.binaryValue() == null && fieldVal.stringValue() == null)) {
continue;
}
tempTerm = (fieldVal.stringValue() != null) ? new BytesRef(fieldVal.stringValue()) : fieldVal.binaryValue();
currentPayload = tempPayload;
currentWeight = getWeight(doc, currentDocId);
return tempTerm;
}
return null;
}
@Override
public BytesRef payload() {
return currentPayload;
}
@Override
public boolean hasPayloads() {
return hasPayloads;
}
/**
* Returns the value of the <code>weightField</code> for the current document.
* Retrieves the value for the <code>weightField</code> if its stored (using <code>doc</code>)
* or if its indexed as {@link NumericDocValues} (using <code>docId</code>) for the document.
* If no value is found, then the weight is 0.
*/
protected long getWeight(Document doc, int docId) {
IndexableField weight = doc.getField(weightField);
if (weight != null) { // found weight as stored
return (weight.numericValue() != null) ? weight.numericValue().longValue() : 0;
} else if (weightValues != null) { // found weight as NumericDocValue
return weightValues.get(docId);
} else { // fall back
return 0;
}
}
private Set<String> getRelevantFields(String... fields) {
Set<String> relevantFields = new HashSet<String>();
for (String relevantField : fields) {
if (relevantField != null) {
relevantFields.add(relevantField);
}
}
return relevantFields;
}
}
}