@Override
    public int hashCode() {

        int result = expression != null ? expression.hashCode() : 0;
        result = 31 * result + (sourceId != null ? sourceId.hashCode() : 0);
        return result;
    }
In condition {@link Expression} checking events from Table or Window
modules/siddhi-query-api/src/main/java/io/siddhi/query/api/expression/condition/In.java