Add HLRC docs for Delete Lifecycle Policy (#35664)

Adds documenatation for the Delete Lifecycle Policy API to the HLRC
documentation.

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

@@ -137,6 +137,80 @@ public class ILMDocumentationIT extends ESRestHighLevelClientTestCase {
 
     }
 
+    public void testDeletePolicy() throws IOException, InterruptedException {
+        RestHighLevelClient client = highLevelClient();
+
+        // Set up a policy so we have something to delete
+        PutLifecyclePolicyRequest putRequest;
+        {
+            Map<String, Phase> phases = new HashMap<>();
+            Map<String, LifecycleAction> hotActions = new HashMap<>();
+            hotActions.put(RolloverAction.NAME, new RolloverAction(
+                new ByteSizeValue(50, ByteSizeUnit.GB), null, null));
+            phases.put("hot", new Phase("hot", TimeValue.ZERO, hotActions));
+            Map<String, LifecycleAction> deleteActions =
+                Collections.singletonMap(DeleteAction.NAME,
+                    new DeleteAction());
+            phases.put("delete",
+                new Phase("delete",
+                    new TimeValue(90, TimeUnit.DAYS), deleteActions));
+            LifecyclePolicy myPolicy = new LifecyclePolicy("my_policy", phases);
+            putRequest = new PutLifecyclePolicyRequest(myPolicy);
+            AcknowledgedResponse putResponse = client.indexLifecycle().
+                putLifecyclePolicy(putRequest, RequestOptions.DEFAULT);
+            assertTrue(putResponse.isAcknowledged());
+        }
+
+        // tag::ilm-delete-lifecycle-policy-request
+        DeleteLifecyclePolicyRequest request =
+            new DeleteLifecyclePolicyRequest("my_policy"); // <1>
+        // end::ilm-delete-lifecycle-policy-request
+
+        // tag::ilm-delete-lifecycle-policy-execute
+        AcknowledgedResponse response = client.indexLifecycle()
+            .deleteLifecyclePolicy(request, RequestOptions.DEFAULT);
+        // end::ilm-delete-lifecycle-policy-execute
+
+        // tag::ilm-delete-lifecycle-policy-response
+        boolean acknowledged = response.isAcknowledged(); // <1>
+        // end::ilm-delete-lifecycle-policy-response
+
+        assertTrue(acknowledged);
+
+        // Put the policy again so we can delete it again
+        {
+            AcknowledgedResponse putResponse = client.indexLifecycle().
+                putLifecyclePolicy(putRequest, RequestOptions.DEFAULT);
+            assertTrue(putResponse.isAcknowledged());
+        }
+
+        // tag::ilm-delete-lifecycle-policy-execute-listener
+        ActionListener<AcknowledgedResponse> listener =
+            new ActionListener<AcknowledgedResponse>() {
+                @Override
+                public void onResponse(AcknowledgedResponse response) {
+                    boolean acknowledged = response.isAcknowledged(); // <1>
+                }
+
+                @Override
+                public void onFailure(Exception e) {
+                    // <2>
+                }
+            };
+        // end::ilm-delete-lifecycle-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::ilm-delete-lifecycle-policy-execute-async
+        client.indexLifecycle().deleteLifecyclePolicyAsync(request,
+            RequestOptions.DEFAULT, listener); // <1>
+        // end::ilm-delete-lifecycle-policy-execute-async
+
+        assertTrue(latch.await(30L, TimeUnit.SECONDS));
+    }
+
     public void testGetLifecyclePolicy() throws IOException, InterruptedException {
         RestHighLevelClient client = highLevelClient();
 

docs/java-rest/high-level/ilm/delete_lifecycle_policy.asciidoc

@@ -0,0 +1,36 @@
+--
+:api: ilm-delete-lifecycle-policy
+:request: DeleteLifecyclePolicyRequest
+:response: AcknowledgedResponse
+--
+
+[id="{upid}-{api}"]
+=== Delete Lifecycle Policy API
+
+
+[id="{upid}-{api}-request"]
+==== Request
+
+The Delete Lifecycle Policy API allows you to delete an Index Lifecycle
+Management Policy from the cluster.
+
+["source","java",subs="attributes,callouts,macros"]
+--------------------------------------------------
+include-tagged::{doc-tests-file}[{api}-request]
+--------------------------------------------------
+<1> The policy named `my_policy` will be deleted.
+
+[id="{upid}-{api}-response"]
+==== Response
+
+The returned +{response}+ indicates if the delete lifecycle policy request was received.
+
+["source","java",subs="attributes,callouts,macros"]
+--------------------------------------------------
+include-tagged::{doc-tests-file}[{api}-response]
+--------------------------------------------------
+<1> Whether or not the delete lifecycle policy request was acknowledged.
+
+include::../execution.asciidoc[]
+
+

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

@@ -457,6 +457,7 @@ The Java High Level REST Client supports the following Index Lifecycle
 Management APIs:
 
 * <<{upid}-ilm-put-lifecycle-policy>>
+* <<{upid}-ilm-delete-lifecycle-policy>>
 * <<{upid}-ilm-get-lifecycle-policy>>
 * <<{upid}-ilm-start-ilm>>
 * <<{upid}-ilm-stop-ilm>>
@@ -465,6 +466,7 @@ Management APIs:
 
 
 include::ilm/put_lifecycle_policy.asciidoc[]
+include::ilm/delete_lifecycle_policy.asciidoc[]
 include::ilm/get_lifecycle_policy.asciidoc[]
 include::ilm/start_lifecycle_management.asciidoc[]
 include::ilm/stop_lifecycle_management.asciidoc[]