来到最后的功能实现的步骤，功能实现其实很简单，添加一个yang文件，编译，添加接口实现代码，编译，ok，搞定收工。

yang文件编写

yang文件简单理解为是定义接口和传入参数的文件，在hello world项目中定了一个接口叫hello-world,需要传入的参数是：input标签中的name变量，类型为string，输出的信息为outpu标签中定义的greeting变量，类型也是string。

module example {
    yang-version 1;
    namespace "urn:opendaylight:params:xml:ns:yang:example";
    prefix "example";

    revision "2015-01-05" {
        description "Initial revision of example model";
    }

    rpc hello-world {
        input {
            leaf name {
                type string;
            }
        }
        output {
            leaf greeting {
                type string;
            }
        }
    }
}

定义好yang文件之后编译，odl的框架会自动生成很多代码，包括rpc中函数的定义，文件的引用等。

mvn clean install -DskipTests -Dmaven.javadoc.skip=true -Dcheckstyle.skip=true

[INFO] 
[INFO] --- maven-site-plugin:3.6:attach-descriptor (generate-site) @ example-aggregator ---
[INFO] Attaching 'src/site/site.xml' site descriptor with classifier 'site'.
[INFO] ------------------------------------------------------------------------
[INFO] Reactor Summary:
[INFO] 
[INFO] ODL :: org.opendaylight.example :: example-api ..... SUCCESS [ 30.916 s]
[INFO] ODL :: org.opendaylight.example :: example-impl .... SUCCESS [ 4.513 s]
[INFO] ODL :: org.opendaylight.example :: example-cli ..... SUCCESS [ 4.574 s]
[INFO] ODL :: org.opendaylight.example :: example-features SUCCESS [ 20.799 s]
[INFO] ODL :: org.opendaylight.example :: example-karaf ... SUCCESS [01:16 min]
[INFO] ODL :: org.opendaylight.example :: example-artifacts SUCCESS [ 5.072 s]
[INFO] ODL :: org.opendaylight.example :: example-it ...... SUCCESS [ 7.690 s]
[INFO] example ............................................ SUCCESS [ 14.771 s]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 02:53 min
[INFO] Finished at: 2019-09-12T17:02:48+08:00
[INFO] Final Memory: 209M/483M
[INFO] ------------------------------------------------------------------------

hello world 函数

编译顺利完成之后，首先将该RPC注册到系统当中去。编写impl-blueprint.xml文件，注册ExampleProvider。

<?xml version="1.0" encoding="UTF-8"?>
<!-- vi: set et smarttab sw=4 tabstop=4: -->
<!--
Copyright © 2017 worker and others. All rights reserved.

This program and the accompanying materials are made available under the
terms of the Eclipse Public License v1.0 which accompanies this distribution,
and is available at http://www.eclipse.org/legal/epl-v10.html
-->

<blueprint xmlns="http://www.osgi.org/xmlns/blueprint/v1.0.0"
  xmlns:odl="http://opendaylight.org/xmlns/blueprint/v1.0.0"
  odl:use-default-for-reference-types="true">

  <bean id="provider"
    class="org.opendaylight.example.impl.ExampleProvider">
  </bean>
  
  <odl:rpc-implementation ref="provider"/>

</blueprint>

注册好函数之后，最后实现RPC的处理函数。获取input输入的内容，然后返回 ‘hello’ + input的内容。

package org.opendaylight.example.impl;

import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.example.rev150105.ExampleService;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.example.rev150105.HelloWorldInput;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.example.rev150105.HelloWorldOutput;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.example.rev150105.HelloWorldOutputBuilder;
import org.opendaylight.yangtools.yang.common.RpcResult;
import org.opendaylight.yangtools.yang.common.RpcResultBuilder;
import java.util.concurrent.Future;


public class ExampleProvider implements ExampleService {

    @Override
    public Future<RpcResult<HelloWorldOutput>> helloWorld(HelloWorldInput input) {
        HelloWorldOutputBuilder helloBuilder = new HelloWorldOutputBuilder();
        helloBuilder.setGreeting("Hello " + input.getName());
        return RpcResultBuilder.success(helloBuilder.build()).buildFuture();
    }


}

编译文件

mvn clean install -DskipTests -Dmaven.javadoc.skip=true -Dcheckstyle.skip=true

[INFO] --- maven-site-plugin:3.6:attach-descriptor (generate-site) @ example-aggregator ---
[INFO] Attaching 'src/site/site.xml' site descriptor with classifier 'site'.
[INFO] ------------------------------------------------------------------------
[INFO] Reactor Summary:
[INFO] 
[INFO] ODL :: org.opendaylight.example :: example-api ..... SUCCESS [ 35.665 s]
[INFO] ODL :: org.opendaylight.example :: example-impl .... SUCCESS [  5.435 s]
[INFO] ODL :: org.opendaylight.example :: example-cli ..... SUCCESS [  4.453 s]
[INFO] ODL :: org.opendaylight.example :: example-features  SUCCESS [ 26.418 s]
[INFO] ODL :: org.opendaylight.example :: example-karaf ... SUCCESS [01:52 min]
[INFO] ODL :: org.opendaylight.example :: example-artifacts SUCCESS [  5.602 s]
[INFO] ODL :: org.opendaylight.example :: example-it ...... SUCCESS [ 18.424 s]
[INFO] example ............................................ SUCCESS [ 22.318 s]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 04:00 min
[INFO] Finished at: 2019-08-04T17:31:48+08:00
[INFO] Final Memory: 207M/483M
[INFO] ------------------------------------------------------------------------