LUCENE-7899: add missing file

lucene/core/src/java/org/apache/lucene/search/DocValuesFieldExistsQuery.java

@@ -0,0 +1,102 @@
+/*
+ * 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.DocValuesType;
+import org.apache.lucene.index.FieldInfo;
+import org.apache.lucene.index.FieldInfos;
+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 Weight createWeight(IndexSearcher searcher, boolean needsScores, float boost) throws IOException {
+    return new ConstantScoreWeight(this, boost) {
+      @Override
+      public Scorer scorer(LeafReaderContext context) throws IOException {
+        FieldInfos fieldInfos = context.reader().getFieldInfos();
+        FieldInfo fieldInfo = fieldInfos.fieldInfo(field);
+        if (fieldInfo == null) {
+          return null;
+        }
+        DocValuesType dvType = fieldInfo.getDocValuesType();
+        LeafReader reader = context.reader();
+        DocIdSetIterator iterator;
+        switch(dvType) {
+        case NONE:
+          return null;
+        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 new ConstantScoreScorer(this, score(), iterator);
+      }
+    };
+  }
+}