/// <summary>
/// Display DbExpression in a human-readable string.
/// </summary>
/// <returns>String containing human-readable version of the DbExpression.</returns>
public override string ToString()
{
string ret = "";
ret += "(";
if (LeftTerm is DbExpression)
{
ret += ((DbExpression)LeftTerm).ToString();
}
else
{
ret += LeftTerm.ToString();
}
ret += " " + Operator.ToString() + " ";
if (RightTerm is DbExpression)
{
ret += ((DbExpression)RightTerm).ToString();
}
else
{
ret += RightTerm.ToString();
}
ret += ")";
return(ret);
}
public virtual bool Calculate()
{
if ((LeftTerm == null) && (RightTerm == null))
{
return(false);
}
if (LeftTerm == null)
{
return(RightTerm.Calculate());
}
if (RightTerm == null)
{
return(LeftTerm.Calculate());
}
return(BoolOperator());
} // Calculate
public void Evaluate()
{
if (!IsValid())
{
throw new Exception($"Evaluation of predicate has failed. Missing value {LeftTerm.Id}.");
}
if (Evaluated)
{
return;
}
try
{
var operatorType = Type.GetType($"Reasoning.Core.Models.Operators.{Enum.GetName(typeof(OperatorType), Operator)}, Reasoning.Core");
var operatorInstance = (IOperator)Activator.CreateInstance(operatorType);
Result = operatorInstance.Compare(LeftTerm.GetValue(), RightTerm.GetValue());
Evaluated = true;
}
catch (Exception ex)
{
throw new Exception($"Unknown operator instance of predicate", ex);
}
}
public bool IsValid()
{
return(!LeftTerm.IsEmpty() && !RightTerm.IsEmpty());
}
public string GetMissingVariableId()
{
return(LeftTerm.IsEmpty() ? LeftTerm.Id : null);
}
} // constructor
protected override bool BoolOperator()
{
return(LeftTerm.Calculate() || RightTerm.Calculate());
} // BoolOperator
