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/*
* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch 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.elasticsearch.search.lookup;
import org.apache.lucene.search.CollectionStatistics;
import org.elasticsearch.common.util.MinimalMap;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
/**
* Script interface to all information regarding a field.
* */
public class IndexField extends MinimalMap<String, IndexFieldTerm> {
/*
* TermsInfo Objects that represent the Terms are stored in this map when
* requested. Information such as frequency, doc frequency and positions
* information can be retrieved from the TermInfo objects in this map.
*/
private final Map<String, IndexFieldTerm> terms = new HashMap<>();
// the name of this field
private final String fieldName;
/*
* The holds the current reader. We need it to populate the field
* statistics. We just delegate all requests there
*/
private final LeafIndexLookup indexLookup;
/*
* General field statistics such as number of documents containing the
* field.
*/
private final CollectionStatistics fieldStats;
/*
* Represents a field in a document. Can be used to return information on
* statistics of this field. Information on specific terms in this field can
* be accessed by calling get(String term).
*/
public IndexField(String fieldName, LeafIndexLookup indexLookup) throws IOException {
assert fieldName != null;
this.fieldName = fieldName;
assert indexLookup != null;
this.indexLookup = indexLookup;
fieldStats = this.indexLookup.getIndexSearcher().collectionStatistics(fieldName);
}
/* get number of documents containing the field */
public long docCount() throws IOException {
return fieldStats.docCount();
}
/* get sum of the number of words over all documents that were indexed */
public long sumttf() throws IOException {
return fieldStats.sumTotalTermFreq();
}
/*
* get the sum of doc frequencies over all words that appear in any document
* that has the field.
*/
public long sumdf() throws IOException {
return fieldStats.sumDocFreq();
}
// TODO: might be good to get the field lengths here somewhere?
/*
* Returns a TermInfo object that can be used to access information on
* specific terms. flags can be set as described in TermInfo.
*
* TODO: here might be potential for running time improvement? If we knew in
* advance which terms are requested, we could provide an array which the
* user could then iterate over.
*/
public IndexFieldTerm get(Object key, int flags) {
String termString = (String) key;
IndexFieldTerm indexFieldTerm = terms.get(termString);
// see if we initialized already...
if (indexFieldTerm == null) {
indexFieldTerm = new IndexFieldTerm(termString, fieldName, indexLookup, flags);
terms.put(termString, indexFieldTerm);
}
indexFieldTerm.validateFlags(flags);
return indexFieldTerm;
}
/*
* Returns a TermInfo object that can be used to access information on
* specific terms. flags can be set as described in TermInfo.
*/
@Override
public IndexFieldTerm get(Object key) {
// per default, do not initialize any positions info
return get(key, IndexLookup.FLAG_FREQUENCIES);
}
public void setDocIdInTerms(int docId) {
for (IndexFieldTerm ti : terms.values()) {
ti.setDocument(docId);
}
}
}
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