Add HLRC support for enrich get policy API. (#45970)

Changed the signature of AbstractResponseTestCase#createServerTestInstance(...)
to include the randomly selected xcontent type. This is needed for the
creating a server response instance with a query which is represented as BytesReference.
Maybe this should go into a different change?

This PR also includes HLRC docs for the get policy api.

Relates to #32789

client/rest-high-level/src/main/java/org/elasticsearch/client/EnrichClient.java

@@ -21,6 +21,8 @@ package org.elasticsearch.client;
 import org.elasticsearch.action.ActionListener;
 import org.elasticsearch.client.core.AcknowledgedResponse;
 import org.elasticsearch.client.enrich.DeletePolicyRequest;
+import org.elasticsearch.client.enrich.GetPolicyRequest;
+import org.elasticsearch.client.enrich.GetPolicyResponse;
 import org.elasticsearch.client.enrich.PutPolicyRequest;
 
 import java.io.IOException;
@@ -130,4 +132,49 @@ public final class EnrichClient {
             Collections.emptySet()
         );
     }
+
+    /**
+     * Executes the get policy api, which retrieves an enrich policy.
+     *
+     * See <a href="https://www.elastic.co/guide/en/elasticsearch/reference/current/enrich-policy-apis.html#get-policy-api">
+     * the docs</a> for more.
+     *
+     * @param request the {@link PutPolicyRequest}
+     * @param options the request options (e.g. headers), use {@link RequestOptions#DEFAULT} if nothing needs to be customized
+     * @return the response
+     * @throws IOException in case there is a problem sending the request or parsing back the response
+     */
+    public GetPolicyResponse getPolicy(GetPolicyRequest request, RequestOptions options) throws IOException {
+        return restHighLevelClient.performRequestAndParseEntity(
+            request,
+            EnrichRequestConverters::getPolicy,
+            options,
+            GetPolicyResponse::fromXContent,
+            Collections.emptySet()
+        );
+    }
+
+    /**
+     * Asynchronously executes the get policy api, which retrieves an enrich policy.
+     *
+     * See <a href="https://www.elastic.co/guide/en/elasticsearch/reference/current/enrich-policy-apis.html#get-policy-api">
+     * the docs</a> for more.
+     *
+     * @param request the {@link PutPolicyRequest}
+     * @param options the request options (e.g. headers), use {@link RequestOptions#DEFAULT} if nothing needs to be customized
+     * @param listener the listener to be notified upon request completion
+     * @return cancellable that may be used to cancel the request
+     */
+    public Cancellable getPolicyAsync(GetPolicyRequest request,
+                               RequestOptions options,
+                               ActionListener<GetPolicyResponse> listener) {
+        return restHighLevelClient.performRequestAsyncAndParseEntity(
+            request,
+            EnrichRequestConverters::getPolicy,
+            options,
+            GetPolicyResponse::fromXContent,
+            listener,
+            Collections.emptySet()
+        );
+    }
 }

client/rest-high-level/src/main/java/org/elasticsearch/client/EnrichRequestConverters.java

@@ -19,8 +19,10 @@
 package org.elasticsearch.client;
 
 import org.apache.http.client.methods.HttpDelete;
+import org.apache.http.client.methods.HttpGet;
 import org.apache.http.client.methods.HttpPut;
 import org.elasticsearch.client.enrich.DeletePolicyRequest;
+import org.elasticsearch.client.enrich.GetPolicyRequest;
 import org.elasticsearch.client.enrich.PutPolicyRequest;
 
 import java.io.IOException;
@@ -48,4 +50,12 @@ final class EnrichRequestConverters {
         return new Request(HttpDelete.METHOD_NAME, endpoint);
     }
 
+    static Request getPolicy(GetPolicyRequest getPolicyRequest) throws IOException {
+        String endpoint = new RequestConverters.EndpointBuilder()
+            .addPathPartAsIs("_enrich", "policy")
+            .addCommaSeparatedPathParts(getPolicyRequest.getNames())
+            .build();
+        return new Request(HttpGet.METHOD_NAME, endpoint);
+    }
+
 }

client/rest-high-level/src/main/java/org/elasticsearch/client/enrich/GetPolicyRequest.java

@@ -0,0 +1,44 @@
+/*
+ * 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.
+ */
+package org.elasticsearch.client.enrich;
+
+import org.elasticsearch.client.Validatable;
+
+import java.util.List;
+
+public final class GetPolicyRequest implements Validatable {
+
+    private final List<String> names;
+
+    public GetPolicyRequest() {
+        this(List.of());
+    }
+
+    public GetPolicyRequest(String... names) {
+        this(List.of(names));
+    }
+
+    public GetPolicyRequest(List<String> names) {
+        this.names = names;
+    }
+
+    public List<String> getNames() {
+        return names;
+    }
+}

client/rest-high-level/src/main/java/org/elasticsearch/client/enrich/GetPolicyResponse.java

@@ -0,0 +1,55 @@
+/*
+ * 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.
+ */
+package org.elasticsearch.client.enrich;
+
+import org.elasticsearch.common.ParseField;
+import org.elasticsearch.common.xcontent.ConstructingObjectParser;
+import org.elasticsearch.common.xcontent.XContentParser;
+
+import java.io.IOException;
+import java.util.List;
+
+public final class GetPolicyResponse {
+
+    @SuppressWarnings("unchecked")
+    private static final ConstructingObjectParser<GetPolicyResponse, Void> PARSER = new ConstructingObjectParser<>(
+        "get_policy_response",
+        true,
+        args -> new GetPolicyResponse((List<NamedPolicy>) args[0])
+    );
+
+    static {
+        PARSER.declareObjectArray(ConstructingObjectParser.constructorArg(),
+            (p, c) -> NamedPolicy.fromXContent(p), new ParseField("policies"));
+    }
+
+    private final List<NamedPolicy> policies;
+
+    public static GetPolicyResponse fromXContent(XContentParser parser) throws IOException {
+        return PARSER.apply(parser, null);
+    }
+
+    public GetPolicyResponse(List<NamedPolicy> policies) {
+        this.policies = policies;
+    }
+
+    public List<NamedPolicy> getPolicies() {
+        return policies;
+    }
+}

client/rest-high-level/src/main/java/org/elasticsearch/client/enrich/NamedPolicy.java

@@ -0,0 +1,130 @@
+/*
+ * 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.
+ */
+package org.elasticsearch.client.enrich;
+
+import org.elasticsearch.common.ParseField;
+import org.elasticsearch.common.ParsingException;
+import org.elasticsearch.common.bytes.BytesArray;
+import org.elasticsearch.common.bytes.BytesReference;
+import org.elasticsearch.common.xcontent.ConstructingObjectParser;
+import org.elasticsearch.common.xcontent.XContentBuilder;
+import org.elasticsearch.common.xcontent.XContentParser;
+
+import java.io.IOException;
+import java.util.List;
+
+public final class NamedPolicy {
+
+    static final ParseField NAME_FIELD = new ParseField("name");
+    static final ParseField QUERY_FIELD = new ParseField("query");
+    static final ParseField INDICES_FIELD = new ParseField("indices");
+    static final ParseField MATCH_FIELD_FIELD = new ParseField("match_field");
+    static final ParseField ENRICH_FIELDS_FIELD = new ParseField("enrich_fields");
+
+    @SuppressWarnings("unchecked")
+    private static final ConstructingObjectParser<NamedPolicy, String> PARSER = new ConstructingObjectParser<>(
+        "policy",
+        true,
+        (args, policyType) -> new NamedPolicy(
+            policyType,
+            (String) args[0],
+            (BytesReference) args[1],
+            (List<String>) args[2],
+            (String) args[3],
+            (List<String>) args[4]
+        )
+    );
+
+    static {
+        declareParserOptions(PARSER);
+    }
+
+    private static void declareParserOptions(ConstructingObjectParser<?, ?> parser) {
+        parser.declareString(ConstructingObjectParser.constructorArg(), NAME_FIELD);
+        parser.declareObject(ConstructingObjectParser.optionalConstructorArg(), (p, c) -> {
+            XContentBuilder builder = XContentBuilder.builder(p.contentType().xContent());
+            builder.copyCurrentStructure(p);
+            return BytesArray.bytes(builder);
+        }, QUERY_FIELD);
+        parser.declareStringArray(ConstructingObjectParser.constructorArg(), INDICES_FIELD);
+        parser.declareString(ConstructingObjectParser.constructorArg(), MATCH_FIELD_FIELD);
+        parser.declareStringArray(ConstructingObjectParser.constructorArg(), ENRICH_FIELDS_FIELD);
+    }
+
+    public static NamedPolicy fromXContent(XContentParser parser) throws IOException {
+        XContentParser.Token token = parser.currentToken();
+        if (token != XContentParser.Token.START_OBJECT) {
+            token = parser.nextToken();
+        }
+        if (token != XContentParser.Token.START_OBJECT) {
+            throw new ParsingException(parser.getTokenLocation(), "unexpected token");
+        }
+        token = parser.nextToken();
+        if (token != XContentParser.Token.FIELD_NAME) {
+            throw new ParsingException(parser.getTokenLocation(), "unexpected token");
+        }
+        String policyType = parser.currentName();
+        NamedPolicy policy = PARSER.parse(parser, policyType);
+        token = parser.nextToken();
+        if (token != XContentParser.Token.END_OBJECT) {
+            throw new ParsingException(parser.getTokenLocation(), "unexpected token");
+        }
+        return policy;
+    }
+
+    private final String type;
+    private final String name;
+    private final BytesReference query;
+    private final List<String> indices;
+    private final String matchField;
+    private final List<String> enrichFields;
+
+    NamedPolicy(String type, String name, BytesReference query, List<String> indices, String matchField, List<String> enrichFields) {
+        this.type = type;
+        this.name = name;
+        this.query = query;
+        this.indices = indices;
+        this.matchField = matchField;
+        this.enrichFields = enrichFields;
+    }
+
+    public String getType() {
+        return type;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public BytesReference getQuery() {
+        return query;
+    }
+
+    public List<String> getIndices() {
+        return indices;
+    }
+
+    public String getMatchField() {
+        return matchField;
+    }
+
+    public List<String> getEnrichFields() {
+        return enrichFields;
+    }
+}

client/rest-high-level/src/main/java/org/elasticsearch/client/enrich/PutPolicyRequest.java

@@ -19,7 +19,6 @@
 package org.elasticsearch.client.enrich;
 
 import org.elasticsearch.client.Validatable;
-import org.elasticsearch.common.ParseField;
 import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.xcontent.ToXContentObject;
@@ -36,11 +35,6 @@ import java.util.Objects;
 
 public class PutPolicyRequest implements Validatable, ToXContentObject {
 
-    static final ParseField QUERY_FIELD = new ParseField("query");
-    static final ParseField INDICES_FIELD = new ParseField("indices");
-    static final ParseField MATCH_FIELD_FIELD = new ParseField("match_field");
-    static final ParseField ENRICH_FIELDS_FIELD = new ParseField("enrich_fields");
-
     private final String name;
     private final String type;
     private BytesReference query;
@@ -110,12 +104,12 @@ public class PutPolicyRequest implements Validatable, ToXContentObject {
         {
             builder.startObject(type);
             {
-                builder.field(INDICES_FIELD.getPreferredName(), indices);
+                builder.field(NamedPolicy.INDICES_FIELD.getPreferredName(), indices);
                 if (query != null) {
-                    builder.field(QUERY_FIELD.getPreferredName(), asMap(query, builder.contentType()));
+                    builder.field(NamedPolicy.QUERY_FIELD.getPreferredName(), asMap(query, builder.contentType()));
                 }
-                builder.field(MATCH_FIELD_FIELD.getPreferredName(), matchField);
-                builder.field(ENRICH_FIELDS_FIELD.getPreferredName(), enrichFields);
+                builder.field(NamedPolicy.MATCH_FIELD_FIELD.getPreferredName(), matchField);
+                builder.field(NamedPolicy.ENRICH_FIELDS_FIELD.getPreferredName(), enrichFields);
             }
             builder.endObject();
         }

client/rest-high-level/src/test/java/org/elasticsearch/client/EnrichIT.java

@@ -18,17 +18,13 @@
  */
 package org.elasticsearch.client;
 
-import org.apache.http.util.EntityUtils;
 import org.elasticsearch.client.core.AcknowledgedResponse;
 import org.elasticsearch.client.enrich.DeletePolicyRequest;
+import org.elasticsearch.client.enrich.GetPolicyRequest;
+import org.elasticsearch.client.enrich.GetPolicyResponse;
 import org.elasticsearch.client.enrich.PutPolicyRequest;
-import org.elasticsearch.common.xcontent.XContentHelper;
-import org.elasticsearch.common.xcontent.json.JsonXContent;
-import org.elasticsearch.common.xcontent.support.XContentMapValues;
 
-import java.io.IOException;
 import java.util.List;
-import java.util.Map;
 
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.is;
@@ -42,35 +38,22 @@ public class EnrichIT extends ESRestHighLevelClientTestCase {
         AcknowledgedResponse putPolicyResponse = execute(putPolicyRequest, enrichClient::putPolicy, enrichClient::putPolicyAsync);
         assertThat(putPolicyResponse.isAcknowledged(), is(true));
 
-        // TODO: Replace with get policy hlrc code:
-        Request getPolicyRequest = new Request("get", "/_enrich/policy/my-policy");
-        Response getPolicyResponse = highLevelClient().getLowLevelClient().performRequest(getPolicyRequest);
-        assertThat(getPolicyResponse.getHttpResponse().getStatusLine().getStatusCode(), equalTo(200));
-        Map<String, Object> responseBody = toMap(getPolicyResponse);
-        List<?> responsePolicies = (List<?>) responseBody.get("policies");
-        assertThat(responsePolicies.size(), equalTo(1));
-        Map<?, ?> responsePolicy = (Map<?, ?>) responsePolicies.get(0);
-        assertThat(XContentMapValues.extractValue("match.indices", responsePolicy), equalTo(putPolicyRequest.getIndices()));
-        assertThat(XContentMapValues.extractValue("match.match_field", responsePolicy), equalTo(putPolicyRequest.getMatchField()));
-        assertThat(XContentMapValues.extractValue("match.enrich_fields", responsePolicy),
-            equalTo(putPolicyRequest.getEnrichFields()));
+        GetPolicyRequest getPolicyRequest = randomBoolean() ? new GetPolicyRequest("my-policy") : new GetPolicyRequest();
+        GetPolicyResponse getPolicyResponse = execute(getPolicyRequest, enrichClient::getPolicy, enrichClient::getPolicyAsync);
+        assertThat(getPolicyResponse.getPolicies().size(), equalTo(1));
+        assertThat(getPolicyResponse.getPolicies().get(0).getType(), equalTo(putPolicyRequest.getType()));
+        assertThat(getPolicyResponse.getPolicies().get(0).getIndices(), equalTo(putPolicyRequest.getIndices()));
+        assertThat(getPolicyResponse.getPolicies().get(0).getMatchField(), equalTo(putPolicyRequest.getMatchField()));
+        assertThat(getPolicyResponse.getPolicies().get(0).getEnrichFields(), equalTo(putPolicyRequest.getEnrichFields()));
 
         DeletePolicyRequest deletePolicyRequest = new DeletePolicyRequest("my-policy");
         AcknowledgedResponse deletePolicyResponse =
             execute(deletePolicyRequest, enrichClient::deletePolicy, enrichClient::deletePolicyAsync);
         assertThat(deletePolicyResponse.isAcknowledged(), is(true));
 
-        // TODO: Replace with get policy hlrc code:
-        getPolicyRequest = new Request("get", "/_enrich/policy");
-        getPolicyResponse = highLevelClient().getLowLevelClient().performRequest(getPolicyRequest);
-        assertThat(getPolicyResponse.getHttpResponse().getStatusLine().getStatusCode(), equalTo(200));
-        responseBody = toMap(getPolicyResponse);
-        responsePolicies = (List<?>) responseBody.get("policies");
-        assertThat(responsePolicies.size(), equalTo(0));
-    }
-
-    private static Map<String, Object> toMap(Response response) throws IOException {
-        return XContentHelper.convertToMap(JsonXContent.jsonXContent, EntityUtils.toString(response.getEntity()), false);
+        getPolicyRequest = new GetPolicyRequest();
+        getPolicyResponse = execute(getPolicyRequest, enrichClient::getPolicy, enrichClient::getPolicyAsync);
+        assertThat(getPolicyResponse.getPolicies().size(), equalTo(0));
     }
 
 }

client/rest-high-level/src/test/java/org/elasticsearch/client/EnrichRequestConvertersTests.java

@@ -19,8 +19,10 @@
 package org.elasticsearch.client;
 
 import org.apache.http.client.methods.HttpDelete;
+import org.apache.http.client.methods.HttpGet;
 import org.apache.http.client.methods.HttpPut;
 import org.elasticsearch.client.enrich.DeletePolicyRequest;
+import org.elasticsearch.client.enrich.GetPolicyRequest;
 import org.elasticsearch.client.enrich.PutPolicyRequest;
 import org.elasticsearch.client.enrich.PutPolicyRequestTests;
 import org.elasticsearch.test.ESTestCase;
@@ -50,4 +52,30 @@ public class EnrichRequestConvertersTests extends ESTestCase {
         assertThat(result.getEntity(), nullValue());
     }
 
+    public void testGetPolicy() throws Exception {
+        GetPolicyRequest request = new GetPolicyRequest(randomAlphaOfLength(4));
+        Request result = EnrichRequestConverters.getPolicy(request);
+
+        assertThat(result.getMethod(), equalTo(HttpGet.METHOD_NAME));
+        assertThat(result.getEndpoint(), equalTo("/_enrich/policy/" + request.getNames().get(0)));
+        assertThat(result.getParameters().size(), equalTo(0));
+        assertThat(result.getEntity(), nullValue());
+
+        request = new GetPolicyRequest(randomAlphaOfLength(4), randomAlphaOfLength(4));
+        result = EnrichRequestConverters.getPolicy(request);
+
+        assertThat(result.getMethod(), equalTo(HttpGet.METHOD_NAME));
+        assertThat(result.getEndpoint(), equalTo("/_enrich/policy/" + request.getNames().get(0) + "," + request.getNames().get(1)));
+        assertThat(result.getParameters().size(), equalTo(0));
+        assertThat(result.getEntity(), nullValue());
+
+        request = new GetPolicyRequest();
+        result = EnrichRequestConverters.getPolicy(request);
+
+        assertThat(result.getMethod(), equalTo(HttpGet.METHOD_NAME));
+        assertThat(result.getEndpoint(), equalTo("/_enrich/policy"));
+        assertThat(result.getParameters().size(), equalTo(0));
+        assertThat(result.getEntity(), nullValue());
+    }
+
 }

client/rest-high-level/src/test/java/org/elasticsearch/client/documentation/EnrichDocumentationIT.java

@@ -25,6 +25,9 @@ import org.elasticsearch.client.RequestOptions;
 import org.elasticsearch.client.RestHighLevelClient;
 import org.elasticsearch.client.core.AcknowledgedResponse;
 import org.elasticsearch.client.enrich.DeletePolicyRequest;
+import org.elasticsearch.client.enrich.NamedPolicy;
+import org.elasticsearch.client.enrich.GetPolicyRequest;
+import org.elasticsearch.client.enrich.GetPolicyResponse;
 import org.elasticsearch.client.enrich.PutPolicyRequest;
 import org.junit.After;
 
@@ -141,4 +144,53 @@ public class EnrichDocumentationIT extends ESRestHighLevelClientTestCase {
         assertTrue(latch.await(30L, TimeUnit.SECONDS));
     }
 
+    public void testGetPolicy() throws Exception {
+        RestHighLevelClient client = highLevelClient();
+
+        PutPolicyRequest putPolicyRequest = new PutPolicyRequest(
+            "users-policy", "exact_match", List.of("users"),
+            "email", List.of("address", "zip", "city", "state"));
+        client.enrich().putPolicy(putPolicyRequest, RequestOptions.DEFAULT);
+
+        // tag::enrich-get-policy-request
+        GetPolicyRequest getPolicyRequest = new GetPolicyRequest("users-policy");
+        // end::enrich-get-policy-request
+
+        // tag::enrich-get-policy-execute
+        GetPolicyResponse getPolicyResponse =
+            client.enrich().getPolicy(getPolicyRequest, RequestOptions.DEFAULT);
+        // end::enrich-get-policy-execute
+
+        // tag::enrich-get-policy-response
+        List<NamedPolicy> policies = getPolicyResponse.getPolicies(); // <1>
+        NamedPolicy policy = policies.get(0);
+        // end::enrich-get-policy-response
+
+        // tag::enrich-get-policy-execute-listener
+        ActionListener<GetPolicyResponse> listener = new ActionListener<>() {
+            @Override
+            public void onResponse(GetPolicyResponse response) { // <1>
+                List<NamedPolicy> policies = response.getPolicies();
+                NamedPolicy policy = policies.get(0);
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                // <2>
+            }
+        };
+        // end::enrich-get-policy-execute-listener
+
+        // Replace the empty listener by a blocking listener in test
+        final CountDownLatch latch = new CountDownLatch(1);
+        listener = new LatchedActionListener<>(listener, latch);
+
+        // tag::enrich-get-policy-execute-async
+        client.enrich().getPolicyAsync(getPolicyRequest,
+            RequestOptions.DEFAULT, listener); // <1>
+        // end::enrich-get-policy-execute-async
+
+        assertTrue(latch.await(30L, TimeUnit.SECONDS));
+    }
+
 }

client/rest-high-level/src/test/java/org/elasticsearch/client/enrich/GetPolicyResponseTests.java

@@ -0,0 +1,95 @@
+/*
+ * 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.
+ */
+package org.elasticsearch.client.enrich;
+
+import org.elasticsearch.client.AbstractResponseTestCase;
+import org.elasticsearch.common.bytes.BytesArray;
+import org.elasticsearch.common.bytes.BytesReference;
+import org.elasticsearch.common.xcontent.XContentBuilder;
+import org.elasticsearch.common.xcontent.XContentParser;
+import org.elasticsearch.common.xcontent.XContentType;
+import org.elasticsearch.xpack.core.enrich.EnrichPolicy;
+import org.elasticsearch.xpack.core.enrich.action.GetEnrichPolicyAction;
+
+import java.io.IOException;
+import java.io.UncheckedIOException;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.Map;
+
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.nullValue;
+
+public class GetPolicyResponseTests extends AbstractResponseTestCase<GetEnrichPolicyAction.Response, GetPolicyResponse> {
+
+    @Override
+    protected GetEnrichPolicyAction.Response createServerTestInstance(XContentType xContentType) {
+        int numPolicies = randomIntBetween(0, 8);
+        Map<String, EnrichPolicy> policies = new HashMap<>(numPolicies);
+        for (int i = 0; i < numPolicies; i++) {
+            policies.put(randomAlphaOfLength(4), createRandomEnrichPolicy(xContentType));
+        }
+        return new GetEnrichPolicyAction.Response(policies);
+    }
+
+    @Override
+    protected GetPolicyResponse doParseToClientInstance(XContentParser parser) throws IOException {
+        return GetPolicyResponse.fromXContent(parser);
+    }
+
+    @Override
+    protected void assertInstances(GetEnrichPolicyAction.Response serverTestInstance, GetPolicyResponse clientInstance) {
+        assertThat(clientInstance.getPolicies().size(), equalTo(serverTestInstance.getPolicies().size()));
+        for (int i = 0; i < clientInstance.getPolicies().size(); i++) {
+            assertThat(clientInstance.getPolicies().get(i).getType(),
+                equalTo(serverTestInstance.getPolicies().get(i).getPolicy().getType()));
+            assertThat(clientInstance.getPolicies().get(i).getName(),
+                equalTo(serverTestInstance.getPolicies().get(i).getName()));
+            assertThat(clientInstance.getPolicies().get(i).getIndices(),
+                equalTo(serverTestInstance.getPolicies().get(i).getPolicy().getIndices()));
+            if (clientInstance.getPolicies().get(i).getQuery() !=  null) {
+                assertThat(clientInstance.getPolicies().get(i).getQuery(),
+                    equalTo(serverTestInstance.getPolicies().get(i).getPolicy().getQuery().getQuery()));
+            } else {
+                assertThat(serverTestInstance.getPolicies().get(i).getPolicy().getQuery(), nullValue());
+            }
+            assertThat(clientInstance.getPolicies().get(i).getMatchField(),
+                equalTo(serverTestInstance.getPolicies().get(i).getPolicy().getMatchField()));
+            assertThat(clientInstance.getPolicies().get(i).getEnrichFields(),
+                equalTo(serverTestInstance.getPolicies().get(i).getPolicy().getEnrichFields()));
+        }
+    }
+
+    private static EnrichPolicy createRandomEnrichPolicy(XContentType xContentType){
+        try (XContentBuilder builder = XContentBuilder.builder(xContentType.xContent())) {
+            builder.startObject();
+            builder.endObject();
+            BytesReference querySource = BytesArray.bytes(builder);
+            return new EnrichPolicy(
+                randomAlphaOfLength(4),
+                randomBoolean() ? new EnrichPolicy.QuerySource(querySource, xContentType) : null,
+                Arrays.asList(generateRandomStringArray(8, 4, false, false)),
+                randomAlphaOfLength(4),
+                Arrays.asList(generateRandomStringArray(8, 4, false, false))
+            );
+        } catch (IOException e) {
+            throw new UncheckedIOException(e);
+        }
+    }
+}

docs/java-rest/high-level/enrich/get_policy.asciidoc

@@ -0,0 +1,32 @@
+--
+:api: enrich-get-policy
+:request: GetPolicyRequest
+:response: GetPolicyResponse
+--
+
+[id="{upid}-{api}"]
+=== Get Policy API
+
+[id="{upid}-{api}-request"]
+==== Request
+
+The Get Policy API allows to retrieve enrich policies by name
+or all policies if no name is provided.
+
+["source","java",subs="attributes,callouts,macros"]
+--------------------------------------------------
+include-tagged::{doc-tests-file}[{api}-request]
+--------------------------------------------------
+
+[id="{upid}-{api}-response"]
+==== Response
+
+The returned +{response}+ includes the requested enrich policy.
+
+["source","java",subs="attributes,callouts,macros"]
+--------------------------------------------------
+include-tagged::{doc-tests-file}[{api}-response]
+--------------------------------------------------
+<1> The actual enrich policy.
+
+include::../execution.asciidoc[]

docs/java-rest/high-level/supported-apis.asciidoc

@@ -604,6 +604,8 @@ The Java High Level REST Client supports the following Enrich APIs:
 
 * <<{upid}-enrich-put-policy>>
 * <<{upid}-enrich-delete-policy>>
+* <<{upid}-enrich-get-policy>>
 
 include::enrich/put_policy.asciidoc[]
 include::enrich/delete_policy.asciidoc[]
+include::enrich/get_policy.asciidoc[]