LuXugang commented on code in PR #767: URL: https://github.com/apache/lucene/pull/767#discussion_r845715708
########## lucene/core/src/java/org/apache/lucene/search/FieldExistsQuery.java: ########## @@ -0,0 +1,228 @@ +/* + * 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.DocValuesType; +import org.apache.lucene.index.FieldInfo; +import org.apache.lucene.index.FieldInfos; +import org.apache.lucene.index.IndexOptions; +import org.apache.lucene.index.IndexReader; +import org.apache.lucene.index.LeafReader; +import org.apache.lucene.index.LeafReaderContext; +import org.apache.lucene.index.PointValues; +import org.apache.lucene.index.Terms; + +/** + * A {@link Query} that matches documents that contain either a {@link + * org.apache.lucene.document.KnnVectorField}, or a field that indexes norms or doc values. + */ +public class FieldExistsQuery extends Query { + private String field; + + /** Create a query that will match that have a value for the given {@code field}. */ + public FieldExistsQuery(String field) { + this.field = Objects.requireNonNull(field); + } + + public String getField() { + return field; + } + + @Override + public String toString(String field) { + return "FieldExistsQuery [field=" + this.field + "]"; + } + + @Override + public void visit(QueryVisitor visitor) { + if (visitor.acceptField(field)) { + visitor.visitLeaf(this); + } + } + + @Override + public boolean equals(Object other) { + return sameClassAs(other) && field.equals(((FieldExistsQuery) other).field); + } + + @Override + public int hashCode() { + final int prime = 31; + int hash = classHash(); + hash = prime * hash + field.hashCode(); + return hash; + } + + @Override + public Query rewrite(IndexReader reader) throws IOException { + boolean allReadersRewritable = true; + + for (LeafReaderContext context : reader.leaves()) { + LeafReader leaf = context.reader(); + FieldInfos fieldInfos = leaf.getFieldInfos(); + FieldInfo fieldInfo = fieldInfos.fieldInfo(field); + + if (fieldInfo == null) { + allReadersRewritable = false; + break; + } + + if (fieldInfo.hasNorms()) { // the field indexes norms + if (reader.getDocCount(field) != reader.maxDoc()) { + allReadersRewritable = false; + break; + } + } else if (fieldInfo.getVectorDimension() != 0) { // the field indexes vectors + if (leaf.getVectorValues(field).size() != reader.maxDoc()) { + allReadersRewritable = false; + break; + } + } else if (fieldInfo.getDocValuesType() + != DocValuesType.NONE) { // the field indexes doc values or points + + // This optimization is possible due to LUCENE-9334 enforcing a field to always uses the + // same data structures (all or nothing). Since there's no index statistic to detect when + // all documents have doc values for a specific field, FieldExistsQuery can only be + // rewritten to MatchAllDocsQuery for doc values field, when that same field also indexes + // terms or point values which do have index statistics, and those statistics confirm that + // all documents in this segment have values terms or point values. + + Terms terms = leaf.terms(field); + PointValues pointValues = leaf.getPointValues(field); + + if ((terms == null || terms.getDocCount() != leaf.maxDoc()) + && (pointValues == null || pointValues.getDocCount() != leaf.maxDoc())) { + allReadersRewritable = false; + break; + } + } else { + throw new IllegalStateException(buildErrorMsg(fieldInfo)); + } + } + if (allReadersRewritable) { + return new MatchAllDocsQuery(); + } + return super.rewrite(reader); + } + + @Override + public Weight createWeight(IndexSearcher searcher, ScoreMode scoreMode, float boost) { + return new ConstantScoreWeight(this, boost) { + @Override + public Scorer scorer(LeafReaderContext context) throws IOException { + FieldInfos fieldInfos = context.reader().getFieldInfos(); + FieldInfo fieldInfo = fieldInfos.fieldInfo(field); + DocIdSetIterator iterator = null; + + if (fieldInfo == null) { + return null; + } + + if (fieldInfo.hasNorms()) { // the field indexes norms + iterator = context.reader().getNormValues(field); + } else if (fieldInfo.getVectorDimension() != 0) { // the field indexes vectors + iterator = context.reader().getVectorValues(field); + } else if (fieldInfo.getDocValuesType() + != DocValuesType.NONE) { // the field indexes doc values + switch (fieldInfo.getDocValuesType()) { + case NUMERIC: + iterator = context.reader().getNumericDocValues(field); + break; + case BINARY: + iterator = context.reader().getBinaryDocValues(field); + break; + case SORTED: + iterator = context.reader().getSortedDocValues(field); + break; + case SORTED_NUMERIC: + iterator = context.reader().getSortedNumericDocValues(field); + break; + case SORTED_SET: + iterator = context.reader().getSortedSetDocValues(field); + break; + case NONE: Review Comment: Spotless: this `case` seems never reachable? -- This is an automated message from the Apache Git Service. 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