messaging-activemq/src/main/java/org/wildfly/extension/messaging/activemq/ha/ManagementHelper.java
static AbstractAddStepHandler createAddOperation(final String childType, final boolean allowSibling, Collection<? extends AttributeDefinition> attributes) {
        return new ActiveMQReloadRequiredHandlers.AddStepHandler(attributes) {
            @Override
            public void execute(OperationContext context, ModelNode operation) throws OperationFailedException {
                super.execute(context, operation);
                if (!allowSibling) {
                    context.addStep(checkNoOtherSibling(childType), MODEL);
                }
            }
        };
    }
static AbstractAddStepHandler createAddOperation(final String childType, final boolean allowSibling, Collection<? extends AttributeDefinition> attributes) {
        return new ActiveMQReloadRequiredHandlers.AddStepHandler(attributes) {
            @Override
            public void execute(OperationContext context, ModelNode operation) throws OperationFailedException {
                super.execute(context, operation);
                if (!allowSibling) {
                    context.addStep(checkNoOtherSibling(childType), MODEL);
                }
            }
        };
    }
Create an ADD operation that can check that there is no other sibling when the resource is added.

@param childType the type of children to check for the existence of siblings
@param allowSibling whether it is allowed to have sibling for the resource that is added.
@param attributes the attributes of the ADD operation