core: make pull and push data flow controllers generic

[jimmarino]

Feature Request

Currently, ProviderPushTransferDataFlowController and ConsumerPullTransferDataFlowControllerdirectly reference HTTP transfers. The controllers should be made generic so they can serve as the default mechanism for handling interactions via the dataplane client API.

Which Areas Would Be Affected?

EDC Core.

Solution Proposal

ConsumerPullTransferDataFlowController does the following:

 public boolean canHandle(TransferProcess transferProcess) {
    return HTTP_PROXY.equals(transferProcess.getDestinationType());
 }

and ProviderPushTransferDataFlowController:

public boolean canHandle(TransferProcess transferProcess) {
   return !HTTP_PROXY.equals(transferProcess.getDestinationType());
}

To make these generic, we introduce a DataTransferMetadataRegistry:

interface DataTransferMetadataRegistry {

   register(TransferTypeDefinition definition);

   @Nullable
   String flowTypeFor(String transferType);

} 

record TransferTypeDefinition(String transferType, FlowType flowType)

enum FlowType {
   PUSH, PULL
}

Each transfer type (e.g. HTTP_PROXY) will be registered with the metadata registry using a TransferTypeDefinition. A transfer type for HTTP push will also need to be defined.

The push and pull controllers will be registered as priority 0 and use the DataTransferTypeRegistry to determine if they can handle a transfer process by looking up the FlowType. Since the controllers will be registered with the lowest priority, they will only be engaged if no other controllers are registered.

[github-actions]

This issue is stale because it has been open for 28 days with no activity.