Class Strategy<TIn, TOut>

Namespace

PatternKit.Behavioral.Strategy

Assembly

PatternKit.Core.dll

Represents a "first-match-wins" strategy pipeline built from predicate/handler pairs.

public sealed class Strategy<TIn, TOut>

Type Parameters

TIn

The input type accepted by each predicate and handler.

TOut

The output type produced by a matching handler.

Inheritance

object

Strategy<TIn, TOut>

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.ReferenceEquals(object, object)

object.ToString()

Extension Methods

CoercerExtensions.Coerce<T>(object?)

Examples

var strategy = Strategy<int, string>.Create()
    .When(static i => i > 0).Then(static i => "positive")
    .When(static i => i < 0).Then(static i => "negative")
    .Default(static _ => "zero")
    .Build();

var label = strategy.Execute(5); // "positive"

Remarks

Strategy<TIn, TOut> is a simpler, non-out-based variant of TryStrategy<TIn, TOut>. It uses Strategy<TIn, TOut>.Predicate delegates to decide whether a handler applies, and Strategy<TIn, TOut>.Handler delegates to produce the result. The first predicate that returns true determines which handler is executed.

If no predicates match and no default handler is configured, an InvalidOperationException is thrown via NoStrategyMatched<T>().

Methods

Create()

Creates a new Strategy<TIn, TOut>.Builder for constructing a Strategy<TIn, TOut>.

public static Strategy<TIn, TOut>.Builder Create()

Returns

Strategy<TIn, TOut>.Builder

A new Strategy<TIn, TOut>.Builder instance.

Examples

var s = Strategy<string, string>.Create()
    .When(s => string.IsNullOrEmpty(s)).Then(_ => "empty")
    .Default(_ => "other")
    .Build();

var result = s.Execute(""); // "empty"

Execute(in TIn)

Executes the strategy pipeline against the given input.

public TOut Execute(in TIn input)

Parameters

input TIn

The input value.

Returns

TOut

The result from the first matching handler, or the Default(Handler) result if provided.

Remarks

Iterates the registered predicates in the order they were added. The first predicate that returns true causes its corresponding handler to execute and the method returns immediately.

If no predicate matches:

• If a default handler is set, its result is returned.
• Otherwise, NoStrategyMatched<T>() is called, which always throws.

Exceptions

InvalidOperationException

Thrown when no predicates match and no default handler is configured.