org.modeshape.jcr.query.lucene.HasValueQuery Maven / Gradle / Ivy
/*
* ModeShape (http://www.modeshape.org)
* See the COPYRIGHT.txt file distributed with this work for information
* regarding copyright ownership. Some portions may be licensed
* to Red Hat, Inc. under one or more contributor license agreements.
* See the AUTHORS.txt file in the distribution for a full listing of
* individual contributors.
*
* ModeShape is free software. Unless otherwise indicated, all code in ModeShape
* is licensed to you under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* ModeShape is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.modeshape.jcr.query.lucene;
import java.io.IOException;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.FieldSelector;
import org.apache.lucene.document.FieldSelectorResult;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.search.Explanation;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.Scorer;
import org.apache.lucene.search.Searcher;
import org.apache.lucene.search.Weight;
/**
* A Lucene {@link Query} implementation that is satisfied if there is at least one value for a document.
*/
@SuppressWarnings( "deprecation" )
public class HasValueQuery extends Query {
private static final long serialVersionUID = 1L;
protected final String fieldName;
protected final FieldSelector fieldSelector;
/**
* Construct a {@link Query} implementation that scores nodes according to the supplied comparator.
*
* @param fieldName the name of the document field containing the value; may not be null
*/
public HasValueQuery( final String fieldName ) {
this.fieldName = fieldName;
this.fieldSelector = new FieldSelector() {
private static final long serialVersionUID = 1L;
@Override
public FieldSelectorResult accept( String fieldName ) {
return HasValueQuery.this.fieldName.equals(fieldName) ? FieldSelectorResult.LOAD_AND_BREAK : FieldSelectorResult.NO_LOAD;
}
};
}
/**
* {@inheritDoc}
*
* @see org.apache.lucene.search.Query#clone()
*/
@Override
public Object clone() {
return new HasValueQuery(fieldName);
}
/**
* {@inheritDoc}
*
* @see org.apache.lucene.search.Query#createWeight(org.apache.lucene.search.Searcher)
*/
@Override
public Weight createWeight( Searcher searcher ) {
return new ExistsWeight();
}
/**
* {@inheritDoc}
*
* @see org.apache.lucene.search.Query#toString(java.lang.String)
*/
@Override
public String toString( String field ) {
return fieldName + " exists";
}
protected boolean hasValue( IndexReader reader,
int docId ) throws IOException {
Document doc = reader.document(docId, fieldSelector);
String valueString = doc.get(fieldName);
return valueString != null;
}
/**
* Calculates query weights and builds query scores for our NOT queries.
*/
protected class ExistsWeight extends Weight {
private static final long serialVersionUID = 1L;
protected ExistsWeight() {
}
/**
* {@inheritDoc}
*
* @see org.apache.lucene.search.Weight#getQuery()
*/
@Override
public Query getQuery() {
return HasValueQuery.this;
}
/**
* {@inheritDoc}
*
* This implementation always returns a weight factor of 1.0.
*
*
* @see org.apache.lucene.search.Weight#getValue()
*/
@Override
public float getValue() {
return 1.0f; // weight factor of 1.0
}
/**
* {@inheritDoc}
*
* This implementation always returns a normalization factor of 1.0.
*
*
* @see org.apache.lucene.search.Weight#sumOfSquaredWeights()
*/
@Override
public float sumOfSquaredWeights() {
return 1.0f; // normalization factor of 1.0
}
/**
* {@inheritDoc}
*
* This implementation always does nothing, as there is nothing to normalize.
*
*
* @see org.apache.lucene.search.Weight#normalize(float)
*/
@Override
public void normalize( float norm ) {
// No need to do anything here
}
/**
* {@inheritDoc}
*
* @see org.apache.lucene.search.Weight#scorer(org.apache.lucene.index.IndexReader, boolean, boolean)
*/
@Override
public Scorer scorer( IndexReader reader,
boolean scoreDocsInOrder,
boolean topScorer ) {
// Return a custom scorer ...
return new ExistsScorer(reader, this);
}
/**
* {@inheritDoc}
*
* @see org.apache.lucene.search.Weight#explain(org.apache.lucene.index.IndexReader, int)
*/
@Override
public Explanation explain( IndexReader reader,
int doc ) {
return new Explanation(getValue(), getQuery().toString());
}
}
/**
* A scorer for the Path query.
*/
protected class ExistsScorer extends Scorer {
private int docId = -1;
private final int pastMaxDocId;
private final IndexReader reader;
protected ExistsScorer( IndexReader reader,
Weight weight ) {
// We don't care which Similarity we have, because we don't use it. So get the default.
super(weight);
this.reader = reader;
assert this.reader != null;
this.pastMaxDocId = this.reader.maxDoc();
}
/**
* {@inheritDoc}
*
* @see org.apache.lucene.search.DocIdSetIterator#docID()
*/
@Override
public int docID() {
return docId;
}
/**
* {@inheritDoc}
*
* @see org.apache.lucene.search.DocIdSetIterator#nextDoc()
*/
@Override
public int nextDoc() throws IOException {
do {
++docId;
if (docId == pastMaxDocId) return Scorer.NO_MORE_DOCS;
if (reader.isDeleted(docId)) {
// We should skip this document ...
continue;
}
if (hasValue(reader, docId)) return docId;
} while (true);
}
/**
* {@inheritDoc}
*
* @see org.apache.lucene.search.DocIdSetIterator#advance(int)
*/
@Override
public int advance( int target ) throws IOException {
if (target == Scorer.NO_MORE_DOCS) return target;
while (true) {
int doc = nextDoc();
if (doc >= target) return doc;
}
}
/**
* {@inheritDoc}
*
* This method always returns a score of 1.0 for the current document, since only those documents that satisfy the NOT are
* scored by this scorer.
*
*
* @see org.apache.lucene.search.Scorer#score()
*/
@Override
public float score() {
return 1.0f;
}
}
}
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