Add support for knn_vector property type

CHANGELOG.md

@@ -26,6 +26,7 @@ Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 ## [Unreleased 2.x]
 
 ### Added
+- Add support for knn_vector field type ([#529](https://github.com/opensearch-project/opensearch-java/pull/524))
 
 ### Dependencies
 

java-client/src/main/java/org/opensearch/client/opensearch/_types/mapping/FieldType.java

@@ -124,6 +124,7 @@ public enum FieldType implements JsonEnum {
 
 	DenseVector("dense_vector"),
 
+	KnnVector("knn_vector"),
 	;
 
 	private final String jsonValue;

java-client/src/main/java/org/opensearch/client/opensearch/_types/mapping/KnnVectorMethod.java

@@ -0,0 +1,229 @@
+/*
+ * 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 B.V. under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch B.V. 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.client.opensearch._types.mapping;
+
+import java.util.Map;
+import java.util.function.Function;
+
+import javax.annotation.Nullable;
+
+import org.opensearch.client.json.JsonData;
+import org.opensearch.client.json.JsonpDeserializable;
+import org.opensearch.client.json.JsonpDeserializer;
+import org.opensearch.client.json.JsonpMapper;
+import org.opensearch.client.json.JsonpSerializable;
+import org.opensearch.client.json.ObjectBuilderDeserializer;
+import org.opensearch.client.json.ObjectDeserializer;
+import org.opensearch.client.util.ApiTypeHelper;
+import org.opensearch.client.util.ObjectBuilder;
+import org.opensearch.client.util.ObjectBuilderBase;
+
+import jakarta.json.stream.JsonGenerator;
+
+// typedef: _types.mapping.KnnVectorMethod
+
+@JsonpDeserializable
+public class KnnVectorMethod implements JsonpSerializable {
+    /**
+     * Builder for {@link KnnVectorMethod}.
+     */
+
+    public static class Builder extends ObjectBuilderBase implements ObjectBuilder<KnnVectorMethod> {
+        private String name;
+
+        @Nullable
+        private String spaceType;
+
+        @Nullable
+        private String engine;
+
+        @Nullable
+        private Map<String, JsonData> parameters;
+
+        /**
+         * Required - API name: {@code name}
+         */
+        public final Builder name(String value) {
+            this.name = value;
+            return this;
+        }
+
+        /**
+         * API name: {@code space_type}
+         */
+        public final Builder spaceType(@Nullable String value) {
+            this.spaceType = value;
+            return this;
+        }
+
+        /**
+         * API name: {@code engine}
+         */
+        public final Builder engine(@Nullable String value) {
+            this.engine = value;
+            return this;
+        }
+
+        /**
+         * API name: {@code parameters}
+         */
+        public final Builder parameters(@Nullable Map<String, JsonData> map) {
+            this.parameters = _mapPutAll(this.parameters, map);
+            return this;
+        }
+
+        /**
+         * Builds a {@link KnnVectorMethod}.
+         *
+         * @throws NullPointerException
+         *                              if some of the required fields are null.
+         */
+        public KnnVectorMethod build() {
+            _checkSingleUse();
+
+            return new KnnVectorMethod(this);
+        }
+    }
+
+    /**
+     * Json deserializer for {@link KnnVectorMethod}
+     */
+    public static final JsonpDeserializer<KnnVectorMethod> _DESERIALIZER = ObjectBuilderDeserializer
+            .lazy(Builder::new, KnnVectorMethod::setupKnnVectorMethodDeserializer);
+
+    public static KnnVectorMethod of(Function<Builder, ObjectBuilder<KnnVectorMethod>> fn) {
+        return fn.apply(new Builder()).build();
+    }
+
+    protected static void setupKnnVectorMethodDeserializer(
+            ObjectDeserializer<KnnVectorMethod.Builder> op) {
+
+        op.add(Builder::name, JsonpDeserializer.stringDeserializer(), "name");
+        op.add(Builder::spaceType, JsonpDeserializer.stringDeserializer(), "space_type");
+        op.add(Builder::engine, JsonpDeserializer.stringDeserializer(), "engine");
+        op.add(Builder::parameters, JsonpDeserializer.stringMapDeserializer(JsonData._DESERIALIZER), "parameters");
+
+    }
+
+    // ---------------------------------------------------------------------------------------------
+
+    private final String name;
+
+    @Nullable
+    private final String spaceType;
+
+    @Nullable
+    private final String engine;
+
+    @Nullable
+    private final Map<String, JsonData> parameters;
+
+    private KnnVectorMethod(Builder builder) {
+
+        this.name = ApiTypeHelper.requireNonNull(builder.name, this, "name");
+        this.spaceType = builder.spaceType;
+        this.engine = builder.engine;
+        this.parameters = builder.parameters;
+
+    }
+
+    /**
+     * Required - API name: {@code name}
+     */
+    public final String name() {
+        return this.name;
+    }
+
+    /**
+     * API name: {@code space_type}
+     */
+    @Nullable
+    public final String spaceType() {
+        return this.spaceType;
+    }
+
+    /**
+     * API name: {@code engine}
+     */
+    @Nullable
+    public final String engine() {
+        return this.engine;
+    }
+
+    // ---------------------------------------------------------------------------------------------
+
+    /**
+     * API name: {@code parameters}
+     */
+    @Nullable
+    public final Map<String, JsonData> parameters() {
+        return this.parameters;
+    }
+
+    // ---------------------------------------------------------------------------------------------
+
+    /**
+     * Serialize this object to JSON.
+     */
+    public void serialize(JsonGenerator generator, JsonpMapper mapper) {
+        generator.writeStartObject();
+        serializeInternal(generator, mapper);
+        generator.writeEnd();
+    }
+
+    protected void serializeInternal(JsonGenerator generator, JsonpMapper mapper) {
+
+        generator.writeKey("name");
+        generator.write(this.name);
+
+        if (this.spaceType != null) {
+            generator.writeKey("space_type");
+            generator.write(this.spaceType);
+        }
+
+        if (this.engine != null) {
+            generator.writeKey("engine");
+            generator.write(this.engine);
+        }
+
+        if (this.parameters != null) {
+            generator.writeKey("parameters");
+            for (Map.Entry<String, JsonData> item0 : this.parameters.entrySet()) {
+                generator.writeKey(item0.getKey());
+                item0.getValue().serialize(generator, mapper);
+            }
+        }
+
+    }
+
+}