Record Basics

An OEMolRecord is a container class for data that is often used by a Cube. OEMolRecord handles the serialization and deserialization of data that is necessary to pass records between cubes. A field identifies the name and type (.e.g., integer, OEMol, etc..) of a piece of data on the record as well as optional meta data. A record can have any number of fields, but the name of a field on the record must be unique. OEMolRecord supports many built-in field types, which are located on datarecord.Types.

The following three methods on OEMolRecord provide core functionality.

  • record.has_value(field) Returns True if the field has a value.

  • record.get_value(field) Returns a copy of the field’s value.

  • record.set_value(field, value) Sets the field’s value.

Field Parameters

Cubes are often used to read and write fields on records that they receive, and so it becomes necessary to inform a cube about the names of those fields (recall that a field is located on a record by its name). This is accomplished by using a FieldParameter.

A FieldParameter is a StringParameter which is converted into an OEField when a cube is executed, where the field’s name is populated by the value of the parameter. A field_type argument is provided to the FieldParameter constructor, which specifies the corresponding field’s type. The parameter type of a ` FieldParameter` is always a string because it represents the name of a field, not the type of a field.

In the following example, the name of the new int_field added to each record is set by the value of that parameter.

from floe.api import ComputeCube
from orionplatform.mixins import RecordPortsMixin
from orionplatform.parameters import FieldParameter

from datarecord import Types

class SquareIntCube(RecordPortsMixin, ComputeCube):

    int_field = FieldParameter("int_field", Types.Int, required=True)

    def process(self, record, port):
        if record.has_value(self.args.int_field):
            x = record.get_value(self.args.int_field)
            record.set_value(self.args.int_field, x * x)

Primary Molecule

An OEMolRecord supports the concept of a primary molecule. The primary molecule is the ‘default’ molecule for a record. As a best practice, cubes which operate on molecules should operate on the primary molecule by default. A cube may use the PrimaryMolFieldParameter for interacting with a primary molecule. Cube authors may also use the InputMolFieldParameter and OutputMolFieldParameter specializations of PrimaryMolFieldParameter for reading and writing primary molecules, respectively. By default, these two parameters will return the primary molecule field, but can be overridden at runtime to specify a different field for either.

The following example adds explicit hydrogens to a molecule. If the user does not specific either the input or output molecule fields at runtime this cube will read the molecule in from the primary molecule field, modify it and write it out to the primary molecule field (overwriting the input).

from floe.api import ComputeCube
from orionplatform.parameters import PrimaryMolFieldParameter

# Note: oechem must be imported before OpenEye toolkits
from openeye.oechem import OEAddExplicitHydrogens

class SquareIntCube(ComputeCube):
    in_mol_field = PrimaryMolFieldParameter("in_mol_field", read_only=True)
    out_mol_field = PrimaryMolFieldParameter("out_mol_field")

    def process(self, record, port):
        if record.has_value(self.args.in_mol_field):
            mol = record.get_value(self.args.in_mol_field)
            record.set_value(self.args.out_mol_field, mol)