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The StrategyBuilder Service provides a convenient way to create an implementation of the Strategy design pattern.

Another of the Gang Of Four patterns, the strategy pattern as implemented in Tapestry IoC is a kind of late binding.

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The StrategyBuilder service (API) creates a service implementation around a strategy registry.

public interface StrategyBuilder
{
    <S> S build(StrategyRegistry<S> registry);
}

For a given interface (and matching StrategyRegistry), a service implementation is created. The service interface is determined from the strategy registry.

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You convert the configuration into a StrategyRegistry, and use that to build the final service:

  public static MyStrategyService build(Map<Class, MyStrategyService> configuration,
    @InjectService("StrategyBuilder")
    StrategyBuilder builder)
  {
     StategyRegistry<MyStrategyService> registry = StrategyRegistry.newInstance(MyStrategyService.class, configuration);
  
     return builder.build(registry);
  }