委譲メモ

Sample.java

interface SomeService{
  public void fire(String parameter){}
}

// pattern 1 複数のクラスに委譲
class DelegatingSomeService implements SomeService{
  private List<SomeService> services;
  public DelegatingSomeService(List<SomeService> service){
    this.services=service;
  }
  @Override
  public void fire(String parameter){
    this.services.stream().forEach((s)->s.fire(parameter));
  }
}

// ThreadLocalでThreadに応じたオブジェクトに委譲
class ContextProxyService{
  private ThreadLocal<SomeService> local=new ThreadLocal<>();
  
  @Override
  public void fire(Stirng parameter){
    SomeService service=local.get();
    Objects.requireNonNull(service, "Illegal context status").fire(parameter);
  }
  public void setContext(SomeService service){
    local.set();
  }
  public void removeContext(){
    local.remove();
  }
}