[FEATURE] Add builder.copy for external retry logic

[injae-kim]

Is your feature request related to a problem?

index = ..;
targetId = ..;
Bool.QueryBuilder queryBuilder = builder(index, targetId, ..);

return search(queryBuilder);

--

public doc search(queryBuilder) { 
  RxJava.retry(retry -> {
    opensearchClient.search(queryBuilder, ..); // ⭐ on retry, re-use same query builder
  });
}

opensearch-java/java-client/src/main/java/org/opensearch/client/util/ObjectBuilderBase.java

Lines 46 to 49 in dbd93c1

	protected void _checkSingleUse() {
	if (this._used) {
	throw new IllegalStateException("Object builders can only be used once");
	}

java.lang.IllegalStateException: Object builders can only be used once

Users can use external retry logic with query builder like above.
But we can't re-use the same query builder on open search so IllegalStateException exception thrown.

What solution would you like?

Bool.QueryBuilder queryBuilder = builder(index, targetId, ..);
return search(queryBuilder);

--

public doc search(queryBuilder) { 
  RxJava.retry(retry -> {
    opensearchClient.search(queryBuilder.copy(), ..); // ⭐ add builder.copy()
  });
}

If we can use queryBudiler.copy(), it's really useful for several cases!

[injae-kim]

I think builder.copy() is usually supported on many other db-client library so it's okay to add it on openserach java client too. and I think many opensearch user need this feature.

I'm contributor on other opensource so I can make PR so PTAL 🙇

[Xtansia]

Thanks for bringing this up. It should be relatively easy to implement on the generated code. Some things to consider:

• Would you expect this to be a surface-level copy or a clone/deep-copy? Lists & Maps would need to be properly copied as we append to them in builders. But what do we do with nested objects.
• Which use-cases require the builder implementing copy versus just re-using the built object from the builder?