[Parser] Validate and collect all properties from a clause

[snj07]

I want to collect all the properties used for filtering the data and do some validation on them. For example:

String query = "MATCH (start {name: 'v1'}) RETURN count(*) AS COUNT";
var statement = CypherParser.parse(query, options)

In the above query I want to collect vertex property "name". Similarly, I want to collect the properties used in other clauses like WHERE, WITH etc. Is there any possible way to access Clause list of Statement without using reflection so I can collect the properties?
Is it possible to convert org.neo4j.cypherdsl.core.Clause to org.neo4j.cypher.internal.ast.Clause so I can modify the parsed clauses and use Neo4jASTFactory class to create a new Statement?

[ikwattro]

For retrieving the property filters, you can make use of the recent Catalog feature -> https://neo4j-contrib.github.io/cypher-dsl/2023.3.0/#catalog-support

Here is a simple example and the output

    @Test
    void catalog_usage() {
        parseQuery("MATCH (start {name: 'v1'}) RETURN count(*) AS COUNT");

        parseQuery("MATCH (n:Person {name: 'bob'}) WITH n WHERE n.age > 20 RETURN bob");
    }

    private void parseQuery(String query) {
        Statement statement = CypherParser.parse(query);
        var catalog = statement.getCatalog();
        System.out.println("----");
        catalog.getAllPropertyFilters().forEach((key, value) -> {
            var labels = key.owningToken().stream().toList();
            var label = labels.size() > 0 ? labels.get(0) : "NONE";
            var propertyKey = key.name();
            value.forEach(propertyFilter -> {
                var clause = propertyFilter.clause().name();
                var operator = propertyFilter.operator().name();
                var left = propertyFilter.left().toString();
                var right = propertyFilter.right().toString();

                System.out.println("detected property filter on token `%s` for property `%s` during `%s` clause , operator is `%s`, left is `%s` and right is `%s`".formatted(
//                        owningType,
                        label,
                        propertyKey,
                        clause,
                        operator,
                        left,
                        right
                ));
            });
        });
    }

----
detected property filter on token `NONE` for property `name` during `MATCH` clause , operator is `EQUALITY`, left is `InternalPropertyImpl{cypher=start.name}` and right is `StringLiteral{cypher='v1'}`
----
detected property filter on token `Token[type=NODE_LABEL, value=Person]` for property `name` during `MATCH` clause , operator is `EQUALITY`, left is `InternalPropertyImpl{cypher=n.name}` and right is `StringLiteral{cypher='bob'}`
detected property filter on token `Token[type=NODE_LABEL, value=Person]` for property `age` during `WITH` clause , operator is `GREATER_THAN`, left is `InternalPropertyImpl{cypher=n.age}` and right is `NumberLiteral{cypher=20}`

[snj07]

I cannot use 2023.3.0, as I'm using Java 11 and it requires Java 17. Is there any other possible way? Could you also suggest a way to add additional clause/filter in parsed dsl?

[michael-simons]

We don't have plans to backport the catalog feature to Java 8. And in addition, the recent Neo4j parser itself requires JDK 17, so we are bounded on that side anyway.