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§Removing GlobalSettings

If you are keen to use dependency injection, we are recommending that you move out of your GlobalSettings implementation class as much code as possible. Ideally, you should be able to refactor your code so that it is possible to eliminate your GlobalSettings class altogether.

Next follows a method-by-method guide for refactoring your code. Because the APIs are slightly different for Java and Scala, make sure to jump to the appropriate subsection.

Note: If you haven’t yet read about dependency injection in Play, make a point to do it now. Follow the appropriate link to learn about dependency injection in Play with Java or Scala.

§Scala

• GlobalSettings.beforeStart and GlobalSettings.onStart: Anything that needs to happen on start up should now be happening in the constructor of a dependency injected class. A class will perform its initialization when the dependency injection framework loads it. If you need eager initialization (because you need to execute some code before the application is actually started), define an eager binding.

• GlobalSettings.onStop: Add a dependency to ApplicationLifecycle on the class that needs to register a stop hook. Then, move the implementation of your GlobalSettings.onStop method inside the Future passed to the ApplicationLifecycle.addStopHook. Read Stopping/cleaning-up for more information.

• GlobalSettings.onError: Create a class that inherits from HttpErrorHandler, and move the implementation of your GlobalSettings.onError inside the HttpErrorHandler.onServerError method. Read Error Handling for more information.

• GlobalSettings.onRequestReceived: Create a class that inherits from HttpRequestHandler, and move the implementation of your GlobalSettings.onRequestReceived inside the HttpRequestHandler.handlerForRequest method. Read Request Handlers for more information.
  Be aware that if in your GlobalSettings.onRequestReceived implementation you are calling super.onRequestReceived, then you should inherits from DefaultHttpRequestHandler instead of HttpRequestHandler, and replace all calls to super.onRequestReceived with super.handlerForRequest.

• GlobalSettings.onRouteRequest: Create a class that inherits from DefaultHttpRequestHandler, and move the implementation of your GlobalSettings.onRouteRequest method inside the DefaultHttpRequestHandler.routeRequest method. Read Request Handlers for more information.

• GlobalSettings.onRequestCompletion: This method is deprecated, and it is no longer invoked by Play. Instead, create a custom filter that attaches an onDoneEnumerating callback onto the returned Enumerator result. Read Scala Http Filters for details on how to create a http filter.

• GlobalSettings.onHandlerNotFound: Create a class that inherits from HttpErrorHandler, and provide an implementation for HttpErrorHandler.onClientError. Read Error Handling for more information.
  Note that HttpErrorHandler.onClientError takes a statusCode in argument, hence your implementation should boil down to:

if(statusCode == play.api.http.Status.NOT_FOUND) {
  // move your implementation of `GlobalSettings.onHandlerNotFound` here
}

• GlobalSettings.onBadRequest: Create a class that inherits from HttpErrorHandler, and provide an implementation for HttpErrorHandler.onClientError. Read Error Handling for more information.
  Note that HttpErrorHandler.onClientError takes a statusCode in argument, hence your implementation should boil down to:

if(statusCode == play.api.http.Status.BAD_REQUEST) {
  // move your implementation of `GlobalSettings.onBadRequest` here
}

• GlobalSettings.configure and GlobalSettings.onLoadConfig: Specify all configuration in your config file or create your own ApplicationLoader (see GuiceApplicationBuilder.loadConfig).

• GlobalSettings.doFilter: Create a class that inherits from HttpFilters, and provide an implementation for HttpFilter.filters. Read Http Filters for more information.

Also, mind that if your Global class is mixing the WithFilters trait, you should now create a Filter class that inherits from HttpFilters, and place it in the empty package. Read here for more details.

§Java

• GlobalSettings.beforeStart and GlobalSettings.onStart: Anything that needs to happen on start up should now be happening in the constructor of a dependency injected class. A class will perform its initialization when the dependency injection framework loads it. If you need eager initialization (for example, because you need to execute some code before the application is actually started), define an eager binding.

• GlobalSettings.onStop: Add a dependency to ApplicationLifecycle on the class that needs to register a stop hook. Then, move the implementation of your GlobalSettings.onStop method inside the Promise passed to the ApplicationLifecycle.addStopHook. Read Stopping/cleaning-up for more information.

• GlobalSettings.onError: Create a class that inherits from HttpErrorHandler, and move the implementation of your GlobalSettings.onError inside the HttpErrorHandler.onServerError method. Read Error Handling for more information.

• GlobalSettings.onRequest: Create a class that inherits from DefaultHttpRequestHandler, and move the implementation of your GlobalSettings.onRequest method inside the DefaultHttpRequestHandler.createAction method. Read Request Handlers for more information.

• GlobalSettings.onRouteRequest: There is no simple migration for this method when using the Java API. If you need this, you will have to keep your Global class around for a little longer.

• GlobalSettings.onHandlerNotFound: Create a class that inherits from HttpErrorHandler, and provide an implementation for HttpErrorHandler.onClientError. Read Error Handling for more information.
  Note that HttpErrorHandler.onClientError takes a statusCode in argument, hence your implementation should boil down to:

if(statusCode == play.mvc.Http.Status.NOT_FOUND) {
  // move your implementation of `GlobalSettings.onHandlerNotFound` here
}

• GlobalSettings.onBadRequest: Create a class that inherits from HttpErrorHandler, and provide an implementation for HttpErrorHandler.onClientError. Read Error Handling for more information.
  Note that HttpErrorHandler.onClientError takes a statusCode in argument, hence your implementation should boil down to:

if(statusCode == play.mvc.Http.Status.BAD_REQUEST) {
  // move your implementation of `GlobalSettings.onBadRequest` here
}

• GlobalSettings.onLoadConfig: Specify all configuration in your config file or create your own ApplicationLoader (see GuiceApplicationBuilder.loadConfig).

• GlobalSettings.filters: Create a class that inherits from HttpFilters, and provide an implementation for HttpFilter.filters. Read Http Filters for more information.

Next: Migrating Anorm

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