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Object Anaylsis Toolkit (OAT) is a rules processing engine to apply provided rules against arbitrary objects

• Rules contain a Target, a Severity, a boolean Expression and a List of Clauses which are applied to the targeted object.
• Clauses perform a specified Operation on a specified Field of a Target. The Field can be any property or subproperty or field of the object specified with dot notation to separate levels.
• The Analyzer has 4 Delegate extensibility points and the built-in operators can also be overridden with delegates.

Basic Usage

The basic usage of OAT is applying rules to targets using the Analyze function.

object target;
IEnumerable<Rule> rules;
var analyzer = new Analyzer();
var rulesWhichApply = analyzer.Analyze(rules,target);

Capturing

OAT also supports capturing the results of clauses.

object target;
IEnumerable<Rule> rules;
var analyzer = new Analyzer();
var res = analyzer.GetCaptures(rules, target);

Example

This sample from the the Walkthrough captures the weight of Overweight vehicles

var overweightTruck = new Vehicle()
{
    Weight = 30000,
    Capacity = 20000,
};

var analyzer = new Analyzer();
analyzer.SetOperation(OverWeightOperation);
var res = analyzer.GetCaptures(rules, overweightTruck);
// We get the First Rule capture and the First Clause Capture
// Since this is our custom operation on an int we know we should get back a TypedClauseCapture<int>
var weight = ((TypedClauseCapture<int>)res.First().Captures[0]).Result;

Assert.IsTrue(weight == 30000);

var overweightRule = new VehicleRule("Overweight Truck")
{
    Expression = "Overweight",
    Target = "Vehicle",
    Clauses = new List<Clause>()
    {
        new Clause(Operation.Custom)
        {
            Label = "Overweight",
            CustomOperation = "OVERWEIGHT",
            Capture = true
        }
    }
}

OatOperation OverweightOperation = new OatOperation(Operation.Custom, analyzer)
{
    CustomOperation = "OVERWEIGHT",
    OperationDelegate = OverweightOperationDelegate,
    ValidationDelegate = OverweightOperationValidationDelegate
};

public OperationResult OverweightOperationDelegate(Clause clause, object? state1, object? state2, IEnumerable<ClauseCapture>? captures)
{
    if (state1 is Vehicle vehicle)
    {
        var res = vehicle.Weight > vehicle.Capacity;
        if ((res && !clause.Invert) || (clause.Invert && !res))
        {
            // The rule applies and is true and the capture is available if capture is enabled
            return new OperationResult(true, clause.Capture ? new TypedClauseCapture<int>(clause, vehicle.Weight, state1, state2) : null);
        }
    }
    return new OperationResult(false, null);
}

public IEnumerable<Violation> OverweightOperationValidationDelegate(Rule r, Clause c)
{
    var violations = new List<Violation>();
    if (r.Target != "Vehicle")
    {
        violations.Add(new Violation("Overweight operation requires a Vehicle object", r, c));
    }

    if (c.Data != null || c.DictData != null)
    {
        violations.Add(new Violation("Overweight operation takes no data.", r, c));
    }
    return violations;
}

Contributing

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This project has adopted the Microsoft Open Source Code of Conduct. For more information see the Code of Conduct FAQ or contact opencode@microsoft.com with any additional questions or comments.