Call jsonb_contains function (postgres) using JPA criteria and JsonBinaryType - postgresql

Question

I have a JPA/Hibernate entity which has a JSONB column (using https://github.com/vladmihalcea/hibernate-types ) for storing a list of strings. This works fine so far.
#TypeDef(name = "jsonb", typeClass = JsonBinaryType.class)
#Type(type = "jsonb")
#Column(name = "TAGS", columnDefinition = "jsonb")
private List<String> tags;
Now I want to check if another string is contained in the list of strings.
I can do this by writing a native query and use the #> operator from Postgres. Because of other reasons (the query is more complex) I do not want to go in that direction. My current approach is calling the jsonb_contains method in a Spring Data specification (since the operator is just alias to this function), e.g. jsonb_contains('["tag1", "tag2", "tag3"]','["tag1"]'). What I am struggling with is, getting the second parameter right.
My initial approach is to also use a List of Strings.
public static Specification<MyEntity> hasTag(String tag) {
return (root, query, cb) -> {
if (StringUtils.isEmpty(tag)) {
return criteriaBuilder.conjunction();
}
Expression<Boolean> expression = criteriaBuilder.function("jsonb_contains",
Boolean.class,
root.get("tags"),
criteriaBuilder.literal(List.of(tag)));
return criteriaBuilder.isTrue(expression);
};
}
This results in the following error.
Caused by: org.postgresql.util.PSQLException: ERROR: function jsonb_contains(jsonb, character varying) does not exist
Hinweis: No function matches the given name and argument types. You might need to add explicit type casts.
Position: 375
It does know that root.get("tags") is mapped to JSONB but for the second parameter it does not. How can I get this right? Is this actually possible?

Answer 1

jsonb_contains(jsob, jsonb) parameters must be jsonb type.
You can not pass a Java String as a parameter to the function.
You can not do casting in Postgresql via JPA Criteria.
Using JSONObject or whatever does not help because Postgresql sees it as
bytea type.
There are 2 possible solutions:
Solution 1
Create jsonb with jsonb_build_object(text[]) function and send it to jsonb_contains(jsonb, jsonb) function:
public static Specification<MyEntity> hasTag(String tag) {
// get List of key-value: [key1, value1, key2, value2...]
List<Object> tags = List.of(tag);
// create jsonb from array list
Expression<?> jsonb = criteriaBuilder.function(
"jsonb_build_object",
Object.class,
cb.literal(tags)
);
Expression<Boolean> expression = criteriaBuilder.function(
"jsonb_contains",
Boolean.class,
root.get("tags"),
jsonb
);
return criteriaBuilder.isTrue(expression);
}
Solution 2
Create custom function in your Postgresql and use it in Java:
SQL:
CREATE FUNCTION jsonb_contains_as_text(a jsonb, b text)
RETURNS BOOLEAN AS $$
SELECT CASE
WHEN a #> b::jsonb THEN TRUE
ELSE FALSE
END;$$
LANGUAGE SQL IMMUTABLE STRICT;
Java Code:
public static Specification<MyEntity> hasTag(String tag) {
Expression<Boolean> expression = criteriaBuilder.function(
"jsonb_contains_as_text",
Boolean.class,
root.get("tags"),
criteriaBuilder.literal(tag)
);
return criteriaBuilder.isTrue(expression);
}

Answer 2

I think that the reason is that you pass the varchar as the second param. jsonb_contains() requires two jsonb params.
To check a jsonb array contains all/any values from a string array you need to use another operators: ?& or ?|.
The methods bindings for them in PSQL 9.4 are: jsonb_exists_all and jsonb_exists_any correspondingly.
In your PSQL version, you could check it by the following command:
select * from pg_operator where oprname = '?&'