Bug 1236 - Documented Binding-aware RPC services of MD-SAL

[controller.git] / opendaylight / md-sal / sal-binding-api / src / main / java / org / opendaylight / controller / sal / binding / api / RpcConsumerRegistry.java

diff --git a/opendaylight/md-sal/sal-binding-api/src/main/java/org/opendaylight/controller/sal/binding/api/RpcConsumerRegistry.java b/opendaylight/md-sal/sal-binding-api/src/main/java/org/opendaylight/controller/sal/binding/api/RpcConsumerRegistry.java
index 7da0a48517fddf715db5f55ced1d431680f0a755..615acd3195c8a99ed5b5f372f53dee46d5faac7b 100644 (file)
--- a/opendaylight/md-sal/sal-binding-api/src/main/java/org/opendaylight/controller/sal/binding/api/RpcConsumerRegistry.java
+++ b/opendaylight/md-sal/sal-binding-api/src/main/java/org/opendaylight/controller/sal/binding/api/RpcConsumerRegistry.java
@@ -10,16 +10,60 @@ package org.opendaylight.controller.sal.binding.api;
 import org.opendaylight.yangtools.yang.binding.RpcService;
 
 /**
- * Base interface defining contract for retrieving MD-SAL
- * version of RpcServices
+ * Provides access to registered Remote Procedure Call (RPC) service implementations. The RPCs are
+ * defined in YANG models.
+ * <p>
+ * RPC implementations are registered using the {@link RpcProviderRegistry}.
  *
  */
 public interface RpcConsumerRegistry extends BindingAwareService {
     /**
-     * Returns a session specific instance (implementation) of requested
-     * YANG module implementation / service provided by consumer.
+     * Returns an implementation of a requested RPC service.
      *
-     * @return Session specific implementation of service
+     * <p>
+     * The returned instance is not an actual implementation of the RPC service
+     * interface, but a proxy implementation of the interface that forwards to
+     * an actual implementation, if any.
+     * <p>
+     *
+     * The following describes the behavior of the proxy when invoking RPC methods:
+     * <ul>
+     * <li>If an actual implementation is registered with the MD-SAL, all invocations are
+     * forwarded to the registered implementation.</li>
+     * <li>If no actual implementation is registered, all invocations will fail by
+     * throwing {@link IllegalStateException}.</li>
+     * <li>Prior to invoking the actual implementation, the method arguments are are validated.
+     * If any are invalid, an {@link IllegalArgumentException} is thrown.
+     * </ul>
+     *
+     * The returned proxy is automatically updated with the most recent
+     * registered implementation.
+     * <p>
+     * The generated RPC method APIs require implementors to return a {@link java.util.concurrent.Future Future}
+     * instance that wraps the {@link org.opendaylight.yangtools.yang.common.RpcResult RpcResult}. Since
+     * RPC methods may be implemented asynchronously, callers should avoid blocking on the
+     * {@link java.util.concurrent.Future Future} result. Instead, it is recommended to use
+     * {@link com.google.common.util.concurrent.JdkFutureAdapters#listenInPoolThread(java.util.concurrent.Future)}
+     * or {@link com.google.common.util.concurrent.JdkFutureAdapters#listenInPoolThread(java.util.concurrent.Future, java.util.concurrent.Executor)}
+     * to listen for Rpc Result. This will asynchronously listen for future result in executor and
+     * will not block current thread.
+     *
+     * <pre>
+     *   final Future<RpcResult<SomeRpcOutput>> future = someRpcService.someRpc( ... );
+     *   Futures.addCallback(JdkFutureAdapters.listenInThreadPool(future), new FutureCallback<RpcResult<SomeRpcOutput>>() {
+     *
+     *       public void onSuccess(RpcResult<SomeRpcOutput> result) {
+     *          // process result ...
+     *       }
+     *
+     *       public void onFailure(Throwable t) {
+     *          // RPC failed
+     *       }
+     *   );
+     * </pre>
+     * @param serviceInterface the interface of the RPC Service. Typically this is an interface generated
+     *                         from a YANG model.
+     * @return the proxy for the requested RPC service. This method never returns null.
      */
-    <T extends RpcService> T getRpcService(Class<T> module);
+    <T extends RpcService> T getRpcService(Class<T> serviceInterface);
 }