CASSANDRA-19931: Support OR operator and sub-conditions in query builder

[lukasz-antoniak]

Fix CASSANDRA-19931.

Example OR operator:

assertThat(
        selectFrom("foo")
            .all()
            .where(Relation.column("k").isEqualTo(literal(1)))
            .and()
            .where(Relation.column("l").isEqualTo(literal(2)))
            .or()
            .where(Relation.column("m").isEqualTo(literal(3)))
            .orderBy("c1", ASC)
            .orderBy("c2", DESC))
    .hasCql("SELECT * FROM foo WHERE k=1 AND l=2 OR m=3 ORDER BY c1 ASC,c2 DESC");

Example sub-condition:

assertThat(
        selectFrom("foo")
            .all()
            .where(Relation.column("k").isEqualTo(literal(1)))
            .and()
            .where(
                subCondition()
                    .where(Relation.column("l").isEqualTo(literal(2)))
                    .or()
                    .where(Relation.column("m").isEqualTo(literal(3))))
            .orderBy("c1", ASC)
            .orderBy("c2", DESC))
    .hasCql("SELECT * FROM foo WHERE k=1 AND (l=2 OR m=3) ORDER BY c1 ASC,c2 DESC");

[Yuqi-Du]

If I understand correctly, this a 'recursive' building.
So we can have

SELECT * FROM foo WHERE k=1 AND (l=2 OR m=3 OR (q=4 AND p=5 )) ORDER BY c1 ASC,c2 DESC"

Or other complex nested logical query?

[lukasz-antoniak]

Yes, you are correct. I have made one of the queries more complex.

[Yuqi-Du]

Is it possible we can add some more complex logical query in tests.

[lukasz-antoniak]

Replaced last test to be more complex. Above tests also verify backward-compatibility of current default AND operator.