simplify DeleteLicenseResponse fromXContent parsing

Author: ywelsch

server/src/main/java/org/elasticsearch/action/support/master/AcknowledgedResponse.java

@@ -39,7 +39,7 @@
  */
 public abstract class AcknowledgedResponse extends ActionResponse implements ToXContentObject {
 
-    protected static final ParseField ACKNOWLEDGED = new ParseField("acknowledged");
+    private static final ParseField ACKNOWLEDGED = new ParseField("acknowledged");
 
     protected static <T extends AcknowledgedResponse> void declareAcknowledgedField(ConstructingObjectParser<T, Void> objectParser) {
         objectParser.declareField(constructorArg(), (parser, context) -> parser.booleanValue(), ACKNOWLEDGED,

x-pack/protocol/src/main/java/org/elasticsearch/protocol/xpack/license/DeleteLicenseResponse.java

@@ -19,30 +19,18 @@
 package org.elasticsearch.protocol.xpack.license;
 
 import org.elasticsearch.action.support.master.AcknowledgedResponse;
-import org.elasticsearch.common.xcontent.ConstructingObjectParser;
 import org.elasticsearch.common.xcontent.XContentParser;
 
-import java.io.IOException;
-
-import static org.elasticsearch.common.xcontent.ConstructingObjectParser.constructorArg;
-
 public class DeleteLicenseResponse extends AcknowledgedResponse {
 
-    private static final ConstructingObjectParser<DeleteLicenseResponse, Void> PARSER = new ConstructingObjectParser<>(
-        "delete_license_response", true, (a, v) -> new DeleteLicenseResponse((Boolean) a[0]));
-
-    static {
-        PARSER.declareBoolean(constructorArg(), AcknowledgedResponse.ACKNOWLEDGED);
-    }
-
     public DeleteLicenseResponse() {
     }
 
     public DeleteLicenseResponse(boolean acknowledged) {
         super(acknowledged);
     }
 
-    public static DeleteLicenseResponse fromXContent(XContentParser parser) throws IOException {
-        return PARSER.parse(parser, null);
+    public static DeleteLicenseResponse fromXContent(XContentParser parser) {
+        return new DeleteLicenseResponse(parseAcknowledged(parser));
     }
 }