Extend MultiValueMode with dedicated support of unsigned_long doc values

Signed-off-by: Andriy Redko <[email protected]>

server/src/main/java/org/opensearch/index/fielddata/FieldData.java

@@ -311,6 +311,18 @@ public static NumericDoubleValues unwrapSingleton(SortedNumericDoubleValues valu
         return null;
     }
 
+    /**
+     * Returns a single-valued view of the {@link SortedNumericDoubleValues},
+     * if it was previously wrapped with {@link DocValues#singleton(NumericDocValues)},
+     * or null.
+     */
+    public static SortedNumericDocValues unwrapSingleton(SortedNumericUnsignedLongValues values) {
+        if (values instanceof SingletonSortedNumericUnsignedLongValues) {
+            return ((SingletonSortedNumericUnsignedLongValues) values).getNumericUnsignedLongValues();
+        }
+        return null;
+    }
+
     /**
      * Returns a multi-valued view over the provided {@link GeoPointValues}.
      */

server/src/main/java/org/opensearch/index/fielddata/SingletonSortedNumericUnsignedLongValues.java

@@ -0,0 +1,78 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * 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.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.index.fielddata;
+
+import org.apache.lucene.index.SortedNumericDocValues;
+
+import java.io.IOException;
+
+/**
+ * Clone of {@link SortedNumericDocValues} for double values.
+ *
+ * @opensearch.internal
+ */
+public final class SingletonSortedNumericUnsignedLongValues extends SortedNumericUnsignedLongValues {
+    private final SortedNumericDocValues values;
+
+    public SingletonSortedNumericUnsignedLongValues(SortedNumericDocValues values) {
+        this.values = values;
+    }
+
+    @Override
+    public boolean advanceExact(int target) throws IOException {
+        return values.advanceExact(target);
+    }
+
+    @Override
+    public long nextValue() throws IOException {
+        return values.nextValue();
+    }
+
+    @Override
+    public int docValueCount() {
+        return values.docValueCount();
+    }
+
+    public int advance(int target) throws IOException {
+        return values.advance(target);
+    }
+
+    public int docID() {
+        return values.docID();
+    }
+
+    /** Return the wrapped values. */
+    public SortedNumericDocValues getNumericUnsignedLongValues() {
+        return values;
+    }
+}

server/src/main/java/org/opensearch/index/fielddata/SortedNumericUnsignedLongValues.java

@@ -0,0 +1,86 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/*
+ * 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.
+ */
+
+/*
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+package org.opensearch.index.fielddata;
+
+import org.apache.lucene.index.SortedNumericDocValues;
+import org.opensearch.common.annotation.PublicApi;
+
+import java.io.IOException;
+
+/**
+ * Clone of {@link SortedNumericDocValues} for unsigned long values.
+ *
+ * @opensearch.api
+ */
+@PublicApi(since = "1.0.0")
+public abstract class SortedNumericUnsignedLongValues {
+
+    /** Sole constructor. (For invocation by subclass
+     * constructors, typically implicit.) */
+    protected SortedNumericUnsignedLongValues() {}
+
+    /** Advance the iterator to exactly {@code target} and return whether
+     *  {@code target} has a value.
+     *  {@code target} must be greater than or equal to the current
+     *  doc ID and must be a valid doc ID, ie. ≥ 0 and
+     *  < {@code maxDoc}.*/
+    public abstract boolean advanceExact(int target) throws IOException;
+
+    /**
+     * Iterates to the next value in the current document. Do not call this more than
+     * {@link #docValueCount} times for the document.
+     */
+    public abstract long nextValue() throws IOException;
+
+    /**
+     * Retrieves the number of values for the current document.  This must always
+     * be greater than zero.
+     * It is illegal to call this method after {@link #advanceExact(int)}
+     * returned {@code false}.
+     */
+    public abstract int docValueCount();
+
+    /**
+     * Advances to the first beyond the current whose document number is greater than or equal to
+     * <i>target</i>, and returns the document number itself. Exhausts the iterator and returns {@link
+     * org.apache.lucene.search.DocIdSetIterator#NO_MORE_DOCS} if <i>target</i> is greater than the highest document number in the set.
+     *
+     * This method is being used by {@link org.apache.lucene.search.comparators.NumericComparator.NumericLeafComparator} when point values optimization kicks
+     * in and is implemented by most numeric types.
+     */
+    public int advance(int target) throws IOException {
+        throw new UnsupportedOperationException();
+    }
+
+    public abstract int docID();
+}