Class ContextHandlerCollection

All Implemented Interfaces:
Handler, Handler.Collection, Handler.Container, Request.Handler, Container, Destroyable, Dumpable, Dumpable.DumpableContainer, LifeCycle, Invocable

@ManagedObject("Context Handler Collection") public class ContextHandlerCollection extends Handler.Sequence
Creates a Map of contexts to it's contained handlers based on the context path and virtual hosts of any contained ContextHandlers. The contexts do not need to be directly contained, only children of the contained handlers. Multiple contexts may have the same context path and they are called in order until one handles the request.
  • Constructor Details

    • ContextHandlerCollection

      public ContextHandlerCollection(ContextHandler... contexts)
    • ContextHandlerCollection

      public ContextHandlerCollection(boolean dynamic, ContextHandler... contexts)
      Parameters:
      dynamic - If true, then contexts may be added dynamically once started, so the InvocationType is assumed to be BLOCKING, otherwise the InvocationType is fixed once started and handlers cannot be subsequently added.
      contexts - The contexts to add.
  • Method Details

    • mapContexts

      @ManagedOperation(value="Update the mapping of context path to context", impact="ACTION") public void mapContexts()
      Remap the contexts. Normally this is not required as context mapping is maintained as a side effect of Handler.Collection.setHandlers(Handler[]) However, if configuration changes in the deep handler structure (eg contextpath is changed), then this call will trigger a remapping. This method is mutually excluded from deployHandler(Handler, Callback) and undeployHandler(Handler, Callback)
    • newHandlers

      protected List<Handler> newHandlers(List<Handler> handlers)
      Overrides:
      newHandlers in class Handler.Sequence
    • handle

      public boolean handle(Request request, Response response, Callback callback) throws Exception
      Description copied from interface: Request.Handler

      Invoked to handle the passed HTTP request and response.

      The request is accepted by returning true, then handling must be concluded by completing the passed callback. The handling may be asynchronous, i.e. this method may return true and complete the given callback later, possibly from a different thread. If this method returns false, then the callback must not be invoked and any mutation on the response reversed.

      Exceptions thrown by this method may be subsequently handled by an error Request.Handler, if present, otherwise a default HTTP 500 error is generated and the callback completed while writing the error response.

      The simplest implementation is:

       public boolean handle(Request request, Response response, Callback callback)
       {
           callback.succeeded();
           return true;
       }
       

      A HelloWorld implementation is:

       public boolean handle(Request request, Response response, Callback callback)
       {
           response.write(true, ByteBuffer.wrap("Hello World\n".getBytes(StandardCharsets.UTF_8)), callback);
           return true;
       }
       
      Specified by:
      handle in interface Request.Handler
      Overrides:
      handle in class Handler.Sequence
      Parameters:
      request - the HTTP request to handle
      response - the HTTP response to handle
      callback - the callback to complete when the handling is complete
      Returns:
      True if and only if the request will be handled, a response generated and the callback eventually called. This may occur within the scope of the call to this method, or asynchronously some time later. If false is returned, then this method must not generate a response, nor complete the callback.
      Throws:
      Exception - if there is a failure during the handling. Catchers cannot assume that the callback will be called and thus should attempt to complete the request as if a false had been returned.
      See Also:
    • getContextPaths

      @ManagedAttribute("The paths of the contexts in this collection") public Set<String> getContextPaths()
    • deployHandler

      public void deployHandler(Handler handler, Callback callback)
      Thread safe deploy of a Handler.

      This method is the equivalent of Handler.Collection.addHandler(Handler), but its execution is non-blocking and mutually excluded from all other callers to itself and undeployHandler(Handler, Callback). The handler may be added after this call returns.

      Parameters:
      handler - the handler to deploy
      callback - Called after handler has been added
    • undeployHandler

      public void undeployHandler(Handler handler, Callback callback)
      Thread safe undeploy of a Handler.

      This method is the equivalent of Handler.Collection.removeHandler(Handler), but its execution is non-block and mutually excluded from all other calls to deployHandler(Handler, Callback) and itself. The handler may be removed after this call returns.

      Parameters:
      handler - The handler to undeploy
      callback - Called after handler has been removed