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Apache Lucene (module: 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.
*/
package org.apache.lucene.search.suggest;
import java.io.IOException;
import java.util.Collections;
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.MultiBits;
import org.apache.lucene.index.MultiDocValues;
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;
/**
*
* Dictionary with terms, weights, payload (optional) and contexts (optional)
* information taken from stored/indexed fields in a Lucene index.
*
* NOTE:
*
* -
* The term field has to be stored; if it is missing, the document is skipped.
*
* -
* The payload and contexts field are optional and are not required to be stored.
*
* -
* 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
0
*
*
*/
public class DocumentDictionary implements Dictionary {
/** {@link IndexReader} to load documents from */
protected final IndexReader reader;
/** Field to read payload from */
protected final String payloadField;
/** Field to read contexts from */
protected final String contextsField;
private final String field;
private final String weightField;
/**
* Creates a new dictionary with the contents of the fields named field
* for the terms and weightField 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 field
* for the terms, weightField for the weights that will be used for the
* the corresponding terms and payloadField for the corresponding payloads
* for the entry.
*/
public DocumentDictionary(IndexReader reader, String field, String weightField, String payloadField) {
this(reader, field, weightField, payloadField, null);
}
/**
* Creates a new dictionary with the contents of the fields named field
* for the terms, weightField for the weights that will be used for the
* the corresponding terms, payloadField for the corresponding payloads
* for the entry and contextsField for associated contexts.
*/
public DocumentDictionary(IndexReader reader, String field, String weightField, String payloadField, String contextsField) {
this.reader = reader;
this.field = field;
this.weightField = weightField;
this.payloadField = payloadField;
this.contextsField = contextsField;
}
@Override
public InputIterator getEntryIterator() throws IOException {
return new DocumentInputIterator(payloadField!=null, contextsField!=null);
}
/** Implements {@link InputIterator} from stored fields. */
protected class DocumentInputIterator implements InputIterator {
private final int docCount;
private final Set relevantFields;
private final boolean hasPayloads;
private final boolean hasContexts;
private final Bits liveDocs;
private int currentDocId = -1;
private long currentWeight = 0;
private BytesRef currentPayload = null;
private Set currentContexts;
private final NumericDocValues weightValues;
IndexableField[] currentDocFields = new IndexableField[0];
int nextFieldsPosition = 0;
/**
* Creates an iterator over term, weight and payload fields from the lucene
* index. setting withPayload to false, implies an iterator
* over only term and weight.
*/
public DocumentInputIterator(boolean hasPayloads, boolean hasContexts) throws IOException {
this.hasPayloads = hasPayloads;
this.hasContexts = hasContexts;
docCount = reader.maxDoc() - 1;
weightValues = (weightField != null) ? MultiDocValues.getNumericValues(reader, weightField) : null;
liveDocs = (reader.leaves().size() > 0) ? MultiBits.getLiveDocs(reader) : null;
relevantFields = getRelevantFields(new String [] {field, weightField, payloadField, contextsField});
}
@Override
public long weight() {
return currentWeight;
}
@Override
public BytesRef next() throws IOException {
while (true) {
if (nextFieldsPosition < currentDocFields.length) {
// Still values left from the document
IndexableField fieldValue = currentDocFields[nextFieldsPosition++];
if (fieldValue.binaryValue() != null) {
return fieldValue.binaryValue();
} else if (fieldValue.stringValue() != null) {
return new BytesRef(fieldValue.stringValue());
} else {
continue;
}
}
if (currentDocId == docCount) {
// Iterated over all the documents.
break;
}
currentDocId++;
if (liveDocs != null && !liveDocs.get(currentDocId)) {
continue;
}
Document doc = reader.document(currentDocId, relevantFields);
BytesRef tempPayload = null;
if (hasPayloads) {
IndexableField payload = doc.getField(payloadField);
if (payload != null) {
if (payload.binaryValue() != null) {
tempPayload = payload.binaryValue();
} else if (payload.stringValue() != null) {
tempPayload = new BytesRef(payload.stringValue());
}
}
// in case that the iterator has payloads configured, use empty values
// instead of null for payload
if (tempPayload == null) {
tempPayload = new BytesRef();
}
}
Set tempContexts;
if (hasContexts) {
tempContexts = new HashSet<>();
final IndexableField[] contextFields = doc.getFields(contextsField);
for (IndexableField contextField : contextFields) {
if (contextField.binaryValue() != null) {
tempContexts.add(contextField.binaryValue());
} else if (contextField.stringValue() != null) {
tempContexts.add(new BytesRef(contextField.stringValue()));
} else {
continue;
}
}
} else {
tempContexts = Collections.emptySet();
}
currentDocFields = doc.getFields(field);
nextFieldsPosition = 0;
if (currentDocFields.length == 0) { // no values in this document
continue;
}
IndexableField fieldValue = currentDocFields[nextFieldsPosition++];
BytesRef tempTerm;
if (fieldValue.binaryValue() != null) {
tempTerm = fieldValue.binaryValue();
} else if (fieldValue.stringValue() != null) {
tempTerm = new BytesRef(fieldValue.stringValue());
} else {
continue;
}
currentPayload = tempPayload;
currentContexts = tempContexts;
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 weightField for the current document.
* Retrieves the value for the weightField if it's stored (using doc)
* or if it's indexed as {@link NumericDocValues} (using docId) for the document.
* If no value is found, then the weight is 0.
*/
protected long getWeight(Document doc, int docId) throws IOException {
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
if (weightValues.docID() < docId) {
weightValues.advance(docId);
}
if (weightValues.docID() == docId) {
return weightValues.longValue();
} else {
// missing
return 0;
}
} else { // fall back
return 0;
}
}
private Set getRelevantFields(String... fields) {
Set relevantFields = new HashSet<>();
for (String relevantField : fields) {
if (relevantField != null) {
relevantFields.add(relevantField);
}
}
return relevantFields;
}
@Override
public Set contexts() {
if (hasContexts) {
return currentContexts;
}
return null;
}
@Override
public boolean hasContexts() {
return hasContexts;
}
}
}