feat: add class to represent nested conditions #259

datagateway_api/src/search_api/nested_where_filters.py

@@ -0,0 +1,30 @@
+class NestedWhereFilters:
+    def __init__(self, lhs, rhs, joining_operator):
+        """
+        Class to represent nested conditions that use different boolean operators e.g.
+        `(A OR B) AND (C OR D)`. This works by joining the two conditions with a boolean
+        operator
+
+        :param lhs: Left hand side of the condition - either a string condition, WHERE
+            filter or instance of this class
+        :type lhs: Any class that has `__str__()` implemented, but use cases will be for
+            :class:`str` or :class:`SearchAPIWhereFilter` or :class:`NestedWhereFilters`
+        :param rhs: Right hand side of the condition - either a string condition, WHERE
+            filter or instance of this class
+        :type rhs: Any class that has `__str__()` implemented, but use cases will be for
+            :class:`str` or :class:`SearchAPIWhereFilter` or :class:`NestedWhereFilters`
+        :param joining_operator: Boolean operator used to join the conditions of `lhs`
+            `rhs` (e.g. `AND` or `OR`)
+        :type joining_operator: :class:`str`
+        """
+
+        self.lhs = str(lhs)
+        self.rhs = str(rhs)
+        self.joining_operator = joining_operator
+
+    def __str__(self):
+        """
+        Join the condition on the left with the one on the right with the boolean
+        operator
+        """
+        return f"({self.lhs} {self.joining_operator} {self.rhs})"