Better syntax for OR/AND Criterias [DATAMONGO-317]

[spring-projects-issues]

Sergey Alaev opened DATAMONGO-317 and commented

To create query {$or: [{'a': 1}, {'b', 2}]} I need to write following code:

Criteria crit1 = Criteria.where("a").is(1);
Criteria crit2 = Criteria.where("b").is(2);
Query query = Query.query(new Criteria().orOperator(crit1, crit2));

I believe it is a good idea to add static or/and factory methods to cover above case and provide a simple way to convert Critera to Query

Something like that:
Query query = Criteria.or(authorCrit, workersCrit).query();

---

Affects: 1.0 M5

2 votes, 3 watchers

[spring-projects-issues]

Mark Pollack commented

Just to note there are a few comments on some changes to syntax we are considering, see caa245d#commitcomment-709242

The suggestion of Criteria.or(authorCrit, workersCrit).query(); would mean that one would also expect to have a corresponding for 'and', e.g.

Criteria.and(authorCrit, workersCrit).query()

which conflicts with the current use of 'and' to join together criteria on different fields.

i think the .query() at the end is an interesting idea, we should gather some more comments, but i'm personally ok w/ just putting it at the start, e.g. query(new Criteria().orOperator(crit1, crit2));

[spring-projects-issues]

Russell Morrisey commented

I agree with Sergey's proposed change. The current usage of orOperator() is not intuitive (coming from a Hibernate background), and it does not jive with the lexical structure of the native mongo $or operator. Consider the following query document:

{ $or: [{'attributes.name': 'MY_ID', 'attributes.value': 123}, {'attributes.name': 'MY_NAME', 'attributes.value:' 'Test'}] }

This is structured like ```
or(cond1, cond2, ... condn)

```cond1.or(cond2, ... condn)

If I am chaining N criteria together, I feel like the existing syntax creates additional burden in my querying code. Here is the code I came up with to "or" a list of criteria:

Criteria criteria = null;
if (criteriaList.size() == 1) {
    criteria = criteriaList.get(0);
}
else if (criteriaList.size() > 1) {
    criteria = criteriaList.get(0).orOperator(criteriaList.subList(1, criteriaList.size()).toArray(new Criteria[]{}));
}

Here is the equivalent code using the proposed syntax:

Criteria criteria = null;
if (criteriaList.size() > 0) {
    criteria = or(criteriaList.toArray(new Criteria[]{})));
}

[spring-projects-issues]

Russell Morrisey commented

The following syntax (provided on the forum by Andrei) is a more correct and more compact solution to the problem:

Query query = new Query(new Criteria().orOperator(
	where("key.attributes")...,
	where("key.attributes")...)
));

This seems to be the only way to get the desired result. I feel like using an empty criteria object is not an intuitive, nor obvious use of the API. What I want to write is:

Query query = new Query(or(
	where("key.attributes")...,
	where("key.attributes")...)
));

The same rational applies to ```
$and