+ * There are 2 types of RPCs: + *
+ * An RPC is global if there is intended to be only 1 registered implementation. A global RPC is not + * explicitly declared as such, essentially any RPC that is not defined to be routed is considered global. + * + *
+ * Global RPCs are registered using the + * {@link #addRpcImplementation(Class, RpcService)} method. + * + *
+ * MD-SAL supports routing of RPC between multiple implementations where the appropriate + * implementation is selected at run time based on the content of the RPC message as described in + * YANG model. + * + *
+ * RPC routing is based on: + *
+ * A context type is modeled in YANG using a combination of a YANG identity
+ * and Opendaylight specific extensions from yang-ext module. These extensions are:
+ *
identity.
+ * Instance identifiers that reference these nodes are valid route identifiers for RPCs that
+ * reference this context type.instance-identifier as a reference to the particular context type defined by the
+ * specified context identity. The value of this
+ * leaf is used by the RPC broker at run time to route the RPC request to the correct implementation.
+ * Note that context-reference may only be used on leaf elements of type
+ * instance-identifier or a type derived from instance-identifier.
+ *
+ * The following snippet declares a simple YANG identity named example-context:
+ *
+ * {@code
+ * module example {
+ * ...
+ * identity example-context {
+ * description "Identity used to define an example-context type";
+ * }
+ * ...
+ * }
+ * }
+ *
+ *
+ * We then use the declared identity to define a context type by using it in combination
+ * with the context-instance YANG extension. We'll associate the context type
+ * with a list element in the data tree. This defines the set of nodes whose instance
+ * identifiers are valid for the example-context context type.
+ *
+ *
+ * The following YANG snippet imports the yang-ext module and defines the list
+ * element named item inside a container named foo:
+ *
+ * {@code
+ * module foo {
+ * ...
+ * import yang-ext {prefix ext;}
+ * ...
+ * container foo {
+ * list item {
+ * key "id";
+ * leaf id {type string;}
+ * ext:context-instance "example-context";
+ * }
+ * }
+ * ...
+ * }
+ * }
+ *
+ *
+ * The statement ext:context-instance "example-context"; inside the list element
+ * declares that any instance identifier referencing item in the data
+ * tree is valid for example-context. For example, the following instance
+ * identifier:
+ *
+ * InstanceIdentifier.create(Foo.class).child(Item.class,new ItemKey("Foo"))
+ *
+ * is valid for example-context. However the following:
+ * + * InstanceIdentifier.create(Example.class) + *+ * is not valid. + * + *
+ * So using an identity in combination with context-instance we
+ * have effectively defined a context type that can be referenced in a YANG RPC input.
+ *
+ *
+ *
+ * To define an RPC to be routed based on the context type we need to add an input leaf element + * that references the context type which will hold an instance identifier value to be + * used to route the RPC. + * + *
+ * The following snippet defines an RPC named show-item with 2 leaf elements
+ * as input: item of type instance-identifier and description:
+ *
+ *
+ * module foo {
+ * ...
+ * import yang-ext {prefix ext;}
+ * ...
+ * rpc show-item {
+ * input {
+ * leaf item {
+ * type instance-identifier;
+ * ext:context-reference example-context;
+ * }
+ * leaf description {
+ * type "string";
+ * }
+ * }
+ * }
+ * }
+ *
+ *
+ *
+ * We mark the item leaf with a context-reference statement that
+ * references the example-context context type. RPC calls will then be routed
+ * based on the instance identifier value contained in item. Only instance
+ * identifiers that point to a foo/item node are valid as input.
+ *
+ *
+ * The generated RPC Service interface for the module is: + * + *
+ * interface FooService implements RpcService {
+ * Future<RpcResult<Void>> showItem(ShowItemInput input);
+ * }
+ *
+ *
+ * + * For constructing the RPC input, there are generated classes ShowItemInput and ShowItemInputBuilder. + * + *
+ * To register a routed implementation for the show-item RPC, we must use the
+ * {@link #addRoutedRpcImplementation(Class, RpcService)} method. This
+ * will return a {@link RoutedRpcRegistration} instance which can then be used to register /
+ * unregister routed paths associated with the registered implementation.
+ *
+ *
+ * The following snippet registers myImpl as the RPC implementation for an
+ * item with key "foo":
+ *
+ * // Create the instance identifier path for item "foo"
+ * InstanceIdentifier path = InstanceIdentifier.create(Foo.class).child(Item.class, new ItemKey("foo"));
+ *
+ * // Register myImpl as the implementation for the FooService RPC interface
+ * RoutedRpcRegistration reg = rpcRegistry.addRoutedRpcImplementation(FooService.class, myImpl);
+ *
+ * // Now register for the context type and specific path ID. The context type is specified by the
+ * // YANG-generated class for the example-context identity.
+ * reg.registerPath(ExampleContext.class, path);
+ *
+ *
+ * + * It is also possible to register the same implementation for multiple paths: + * + *
+ * InstanceIdentifier one = InstanceIdentifier.create(Foo.class).child(Item.class, new ItemKey("One"));
+ * InstanceIdentifier two = InstanceIdentifier.create(Foo.class).child(Item.class, new ItemKey("Two"));
+ *
+ * RoutedRpcRegistration reg = rpcRegistry.addRoutedRpcImplementation(FooService.class, myImpl);
+ * reg.registerPath(ExampleContext.class, one);
+ * reg.registerPath(ExampleContext.class, two);
+ *
+ *
+ *
+ * When another client invokes the showItem(ShowItemInput) method on the proxy instance
+ * retrieved via {@link RpcConsumerRegistry#getRpcService(Class)}, the proxy will inspect the
+ * arguments in ShowItemInput, extract the InstanceIdentifier value of the item leaf and select
+ * the implementation whose registered path matches the InstanceIdentifier value of the item leaf.
+ *
+ *
+ *
+ *
+ * The generated interfaces require implementors to return + * {@link java.util.concurrent.Future Future}<{@link org.opendaylight.yangtools.yang.common.RpcResult RpcResult} + * <{RpcName}Output>> instances. + * + *
+ * Implementations should do processing of RPC calls asynchronously and update the + * returned {@link java.util.concurrent.Future Future} instance when processing is complete. + * However using {@link com.google.common.util.concurrent.Futures#immediateFuture(Object) Futures.immediateFuture} + * is valid only if the result is immediately available and asynchronous processing is unnecessary and + * would only introduce additional complexity. + * + *
+ * The {@link org.opendaylight.yangtools.yang.common.RpcResult RpcResult} is a generic + * wrapper for the RPC output payload, if any, and also allows for attaching error or + * warning information (possibly along with the payload) should the RPC processing partially + * or completely fail. This is intended to provide additional human readable information + * for users of the API and to transfer warning / error information across the system + * so it may be visible via other external APIs such as Restconf. + * + *
+ * It is recommended to use the {@link org.opendaylight.yangtools.yang.common.RpcResult RpcResult}
+ * for conveying appropriate error information
+ * on failure rather than purposely throwing unchecked exceptions if at all possible.
+ * While unchecked exceptions will fail the returned {@link java.util.concurrent.Future Future},
+ * using the intended RpcResult to convey the error information is more user-friendly.
+ *
+ * @deprecated Use {@link org.opendaylight.mdsal.binding.api.RpcProviderService} instead
*/
-public interface RpcProviderRegistry extends //
- RpcConsumerRegistry, //
+@Deprecated
+public interface RpcProviderRegistry extends RpcConsumerRegistry,
RouteChangePublisher
+ * See the {@link RpcProviderRegistry class} documentation for information and example on how to use routed RPCs.
+ *
+ * @param serviceInterface the YANG-generated interface of the RPC Service for which to register.
+ * @param implementation the implementation instance to register.
+ * @return a RoutedRpcRegistration instance which can be used to register paths for the RPC
+ * implementation via invoking RoutedRpcRegistration#registerPath(Class, InstanceIdentifer).
+ * {@link RoutedRpcRegistration#close()} should be called to unregister the implementation
+ * and all previously registered paths when no longer needed.
+ * @throws IllegalStateException if the supplied RPC interface is not a routed RPC type.
*/
-