java-client/src/main/java/co/elastic/clients/elasticsearch/indices/update_aliases/Action.java The Builder of Action of updateAliases should use [return self()] instead of [return this] and change the return type to [Builder]

[Jiuyoung]

Java API client version

8.15.1

Java version

11

Elasticsearch Version

8.15.0

Problem description

The following is the relevant code, which is causing the inability to achieve chaining as expected.

elasticsearch-java/java-client/src/main/java/co/elastic/clients/elasticsearch/indices/update_aliases/Action.java

Lines 198 to 230 in 7c46ddd

	public static class Builder extends WithJsonObjectBuilderBase<Builder> implements ObjectBuilder<Action> {
	private Kind _kind;
	private Object _value;
	@Override
	protected Builder self() {
	return this;
	}
	public ObjectBuilder<Action> add(AddAction v) {
	this._kind = Kind.Add;
	this._value = v;
	return this;
	}
	public ObjectBuilder<Action> add(Function<AddAction.Builder, ObjectBuilder<AddAction>> fn) {
	return this.add(fn.apply(new AddAction.Builder()).build());
	}
	public ObjectBuilder<Action> remove(RemoveAction v) {
	this._kind = Kind.Remove;
	this._value = v;
	return this;
	}
	public ObjectBuilder<Action> remove(Function<RemoveAction.Builder, ObjectBuilder<RemoveAction>> fn) {
	return this.remove(fn.apply(new RemoveAction.Builder()).build());
	}
	public ObjectBuilder<Action> removeIndex(RemoveIndexAction v) {
	this._kind = Kind.RemoveIndex;
	this._value = v;
	return this;
	}

[l-trotta]

Hello! I'm a bit confused, since this is the same pattern used in all the classes of the client. Could you show me which kind of chaining are you trying to achieve?

[Jiuyoung]

@l-trotta

Thanks for your comment. The following code describes this situation.

public static void main(String[] args) throws IOException {
    // DESC: I would like to rewrite the following code to use chaining.
    es.indices().updateAliases(
            request -> request.actions(
                    actionsBuilder -> {
                        // DESC: these code used to build actions list
                        actionsBuilder.add(add -> add.alias("alias1").index("index1"));
                        actionsBuilder.add(add -> add.alias("alias1").index("index2"));
                        return actionsBuilder;
                    }
            )
    );
    // DESC: I am trying to write the following code
    es.indices().updateAliases(
            request -> request.actions(
                    actionsBuilder -> actionsBuilder
                            .add(add -> add.alias("alias1").index("index1"))
                            // ERROR: This will not work as expected with error [Cannot resolve method 'add' in 'ObjectBuilder']
                            .add(add -> add.alias("alias1").index("index2"))
            )
    );
}

This picture show code in IDEA.

[l-trotta]

Got it! So for builders that allow multiple values we have 3 types of constructors:

The last one just works for a single value, so to add multiple value you can either use a list:

es.indices().updateAliases(
    u -> u.actions(List.of(Action.of(a -> a
                .add(add -> add
                    .alias("alias1")
                    .index("index1")
                )
            ),
            Action.of(a -> a
                .add(add -> add
                    .alias("alias1")
                    .index("index1")
                )
            )
        )
    )
);

or comma separated values:

es.indices().updateAliases(
    u -> u.actions(Action.of(a -> a
            .add(add -> add
                .alias("alias1")
                .index("index1")
            )
        ),
        Action.of(a -> a
            .add(add -> add
                .alias("alias1")
                .index("index1")
            )
        )
    )
);

We chose this approach to keep the syntax of the request similar to the original json one, which accepts a list of values or a single value.

[Jiuyoung]

^_^ Very nice! Thank you! I will close this issue.