protected T doRefer()

in dubbo-rpc-extensions/dubbo-rpc-rmi/src/main/java/org/apache/dubbo/rpc/protocol/rmi/RmiProtocol.java [75:116]
33 lines of code
7 McCabe index (conditional complexity)

    protected <T> T doRefer(final Class<T> serviceType, final URL url) throws RpcException {
        final RmiProxyFactoryBean rmiProxyFactoryBean = new RmiProxyFactoryBean();
        final String generic = url.getParameter(GENERIC_KEY);
        final boolean isGeneric = ProtocolUtils.isGeneric(generic) || serviceType.equals(GenericService.class);
        /*
          RMI needs extra parameter since it uses customized remote invocation object

          The customized RemoteInvocation was firstly introduced in v2.6.3; The package was renamed to 'org.apache.*' since v2.7.0
          Considering the above two conditions, we need to check before sending customized RemoteInvocation:
          1. if the provider version is v2.7.0 or higher, send 'org.apache.dubbo.rpc.protocol.rmi.RmiRemoteInvocation'.
          2. if the provider version is v2.6.3 or higher, send 'com.alibaba.dubbo.rpc.protocol.rmi.RmiRemoteInvocation'.
          3. if the provider version is lower than v2.6.3, does not use customized RemoteInvocation.
         */
        if (isRelease270OrHigher(url.getParameter(RELEASE_KEY))) {
            rmiProxyFactoryBean.setRemoteInvocationFactory(methodInvocation -> {
                RemoteInvocation invocation = new RmiRemoteInvocation(methodInvocation);
                if (isGeneric) {
                    invocation.addAttribute(GENERIC_KEY, generic);
                }
                return invocation;
            });
        } else if (isRelease263OrHigher(url.getParameter(DUBBO_VERSION_KEY))) {
            rmiProxyFactoryBean.setRemoteInvocationFactory(methodInvocation -> {
                RemoteInvocation invocation = new com.alibaba.dubbo.rpc.protocol.rmi.RmiRemoteInvocation(methodInvocation);
                if (isGeneric) {
                    invocation.addAttribute(GENERIC_KEY, generic);
                }
                return invocation;
            });
        }
        String serviceUrl = url.toIdentityString();
        if (isGeneric) {
            serviceUrl = serviceUrl + "/" + GENERIC_KEY;
        }
        rmiProxyFactoryBean.setServiceUrl(serviceUrl);
        rmiProxyFactoryBean.setServiceInterface(serviceType);
        rmiProxyFactoryBean.setCacheStub(true);
        rmiProxyFactoryBean.setLookupStubOnStartup(true);
        rmiProxyFactoryBean.setRefreshStubOnConnectFailure(true);
        rmiProxyFactoryBean.afterPropertiesSet();
        return (T) rmiProxyFactoryBean.getObject();
    }