| // Protocol Buffers - Google's data interchange format |
| // Copyright 2008 Google Inc. All rights reserved. |
| // https://developers.google.com/protocol-buffers/ |
| // |
| // Redistribution and use in source and binary forms, with or without |
| // modification, are permitted provided that the following conditions are |
| // met: |
| // |
| // * Redistributions of source code must retain the above copyright |
| // notice, this list of conditions and the following disclaimer. |
| // * Redistributions in binary form must reproduce the above |
| // copyright notice, this list of conditions and the following disclaimer |
| // in the documentation and/or other materials provided with the |
| // distribution. |
| // * Neither the name of Google Inc. nor the names of its |
| // contributors may be used to endorse or promote products derived from |
| // this software without specific prior written permission. |
| // |
| // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
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| // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| |
| package com.google.protobuf; |
| |
| /** |
| * Abstract base interface for protocol-buffer-based RPC services. Services |
| * themselves are abstract classes (implemented either by servers or as |
| * stubs), but they subclass this base interface. The methods of this |
| * interface can be used to call the methods of the service without knowing |
| * its exact type at compile time (analogous to the Message interface). |
| * |
| * <p>Starting with version 2.3.0, RPC implementations should not try to build |
| * on this, but should instead provide code generator plugins which generate |
| * code specific to the particular RPC implementation. This way the generated |
| * code can be more appropriate for the implementation in use and can avoid |
| * unnecessary layers of indirection. |
| * |
| * @author kenton@google.com Kenton Varda |
| */ |
| public interface Service { |
| /** |
| * Get the {@code ServiceDescriptor} describing this service and its methods. |
| */ |
| Descriptors.ServiceDescriptor getDescriptorForType(); |
| |
| /** |
| * <p>Call a method of the service specified by MethodDescriptor. This is |
| * normally implemented as a simple {@code switch()} that calls the standard |
| * definitions of the service's methods. |
| * |
| * <p>Preconditions: |
| * <ul> |
| * <li>{@code method.getService() == getDescriptorForType()} |
| * <li>{@code request} is of the exact same class as the object returned by |
| * {@code getRequestPrototype(method)}. |
| * <li>{@code controller} is of the correct type for the RPC implementation |
| * being used by this Service. For stubs, the "correct type" depends |
| * on the RpcChannel which the stub is using. Server-side Service |
| * implementations are expected to accept whatever type of |
| * {@code RpcController} the server-side RPC implementation uses. |
| * </ul> |
| * |
| * <p>Postconditions: |
| * <ul> |
| * <li>{@code done} will be called when the method is complete. This may be |
| * before {@code callMethod()} returns or it may be at some point in |
| * the future. |
| * <li>The parameter to {@code done} is the response. It must be of the |
| * exact same type as would be returned by |
| * {@code getResponsePrototype(method)}. |
| * <li>If the RPC failed, the parameter to {@code done} will be |
| * {@code null}. Further details about the failure can be found by |
| * querying {@code controller}. |
| * </ul> |
| */ |
| void callMethod(Descriptors.MethodDescriptor method, |
| RpcController controller, |
| Message request, |
| RpcCallback<Message> done); |
| |
| /** |
| * <p>{@code callMethod()} requires that the request passed in is of a |
| * particular subclass of {@code Message}. {@code getRequestPrototype()} |
| * gets the default instances of this type for a given method. You can then |
| * call {@code Message.newBuilderForType()} on this instance to |
| * construct a builder to build an object which you can then pass to |
| * {@code callMethod()}. |
| * |
| * <p>Example: |
| * <pre> |
| * MethodDescriptor method = |
| * service.getDescriptorForType().findMethodByName("Foo"); |
| * Message request = |
| * stub.getRequestPrototype(method).newBuilderForType() |
| * .mergeFrom(input).build(); |
| * service.callMethod(method, request, callback); |
| * </pre> |
| */ |
| Message getRequestPrototype(Descriptors.MethodDescriptor method); |
| |
| /** |
| * Like {@code getRequestPrototype()}, but gets a prototype of the response |
| * message. {@code getResponsePrototype()} is generally not needed because |
| * the {@code Service} implementation constructs the response message itself, |
| * but it may be useful in some cases to know ahead of time what type of |
| * object will be returned. |
| */ |
| Message getResponsePrototype(Descriptors.MethodDescriptor method); |
| } |