org.apache.lucene.search.DocValuesFieldExistsQuery.java Source code

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Here is the source code for org.apache.lucene.search.DocValuesFieldExistsQuery.java

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/*
 * 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;

import java.io.IOException;
import java.util.Objects;

import org.apache.lucene.index.DocValues;
import org.apache.lucene.index.FieldInfo;
import org.apache.lucene.index.LeafReader;
import org.apache.lucene.index.LeafReaderContext;

/**
 * A {@link Query} that matches documents that have a value for a given field
 * as reported by doc values iterators.
 */
public final class DocValuesFieldExistsQuery extends Query {

    private final String field;

    /** Create a query that will match that have a value for the given
     *  {@code field}. */
    public DocValuesFieldExistsQuery(String field) {
        this.field = Objects.requireNonNull(field);
    }

    public String getField() {
        return field;
    }

    @Override
    public boolean equals(Object other) {
        return sameClassAs(other) && field.equals(((DocValuesFieldExistsQuery) other).field);
    }

    @Override
    public int hashCode() {
        return 31 * classHash() + field.hashCode();
    }

    @Override
    public String toString(String field) {
        return "DocValuesFieldExistsQuery [field=" + this.field + "]";
    }

    @Override
    public void visit(QueryVisitor visitor) {
        if (visitor.acceptField(field)) {
            visitor.visitLeaf(this);
        }
    }

    @Override
    public Weight createWeight(IndexSearcher searcher, ScoreMode scoreMode, float boost) {
        return new ConstantScoreWeight(this, boost) {
            @Override
            public Scorer scorer(LeafReaderContext context) throws IOException {
                DocIdSetIterator iterator = getDocValuesDocIdSetIterator(field, context.reader());
                if (iterator == null) {
                    return null;
                }
                return new ConstantScoreScorer(this, score(), scoreMode, iterator);
            }

            @Override
            public boolean isCacheable(LeafReaderContext ctx) {
                return DocValues.isCacheable(ctx, field);
            }

        };
    }

    /**
     * Returns a {@link DocIdSetIterator} from the given field or null if the field doesn't exist
     * in the reader or if the reader has no doc values for the field.
     */
    public static DocIdSetIterator getDocValuesDocIdSetIterator(String field, LeafReader reader)
            throws IOException {
        FieldInfo fieldInfo = reader.getFieldInfos().fieldInfo(field);
        final DocIdSetIterator iterator;
        if (fieldInfo != null) {
            switch (fieldInfo.getDocValuesType()) {
            case NONE:
                iterator = null;
                break;
            case NUMERIC:
                iterator = reader.getNumericDocValues(field);
                break;
            case BINARY:
                iterator = reader.getBinaryDocValues(field);
                break;
            case SORTED:
                iterator = reader.getSortedDocValues(field);
                break;
            case SORTED_NUMERIC:
                iterator = reader.getSortedNumericDocValues(field);
                break;
            case SORTED_SET:
                iterator = reader.getSortedSetDocValues(field);
                break;
            default:
                throw new AssertionError();
            }
            return iterator;
        }
        return null;
    }
}