聊聊dubbo-go的RPCInvocation

// Invocation ...
type Invocation interface {
    MethodName() string
    ParameterTypes() []reflect.Type
    ParameterValues() []reflect.Value
    Arguments() []interface{}
    Reply() interface{}
    Attachments() map[string]string
    AttachmentsByKey(string, string) string
    Invoker() Invoker
}

type RPCInvocation struct {
    methodName      string
    parameterTypes  []reflect.Type
    parameterValues []reflect.Value
    arguments       []interface{}
    reply           interface{}
    callBack        interface{}
    attachments     map[string]string
    invoker         protocol.Invoker
    lock            sync.RWMutex
}

// NewRPCInvocation ...
func NewRPCInvocation(methodName string, arguments []interface{}, attachments map[string]string) *RPCInvocation {
    return &RPCInvocation{
        methodName:  methodName,
        arguments:   arguments,
        attachments: attachments,
    }
}

// NewRPCInvocationWithOptions ...
func NewRPCInvocationWithOptions(opts ...option) *RPCInvocation {
    invo := &RPCInvocation{}
    for _, opt := range opts {
        opt(invo)
    }
    return invo
}

type option func(invo *RPCInvocation)

// WithMethodName ...
func WithMethodName(methodName string) option {
    return func(invo *RPCInvocation) {
        invo.methodName = methodName
    }
}

// WithParameterTypes ...
func WithParameterTypes(parameterTypes []reflect.Type) option {
    return func(invo *RPCInvocation) {
        invo.parameterTypes = parameterTypes
    }
}

// WithParameterValues ...
func WithParameterValues(parameterValues []reflect.Value) option {
    return func(invo *RPCInvocation) {
        invo.parameterValues = parameterValues
    }
}

// WithArguments ...
func WithArguments(arguments []interface{}) option {
    return func(invo *RPCInvocation) {
        invo.arguments = arguments
    }
}

// WithReply ...
func WithReply(reply interface{}) option {
    return func(invo *RPCInvocation) {
        invo.reply = reply
    }
}

// WithCallBack ...
func WithCallBack(callBack interface{}) option {
    return func(invo *RPCInvocation) {
        invo.callBack = callBack
    }
}

// WithAttachments ...
func WithAttachments(attachments map[string]string) option {
    return func(invo *RPCInvocation) {
        invo.attachments = attachments
    }
}

// WithInvoker ...
func WithInvoker(invoker protocol.Invoker) option {
    return func(invo *RPCInvocation) {
        invo.invoker = invoker
    }
}

// AttachmentsByKey ...
func (r *RPCInvocation) AttachmentsByKey(key string, defaultValue string) string {
    r.lock.RLock()
    defer r.lock.RUnlock()
    if r.attachments == nil {
        return defaultValue
    }
    value, ok := r.attachments[key]
    if ok {
        return value
    }
    return defaultValue
}

// SetAttachments ...
func (r *RPCInvocation) SetAttachments(key string, value string) {
    r.lock.Lock()
    defer r.lock.Unlock()
    if r.attachments == nil {
        r.attachments = make(map[string]string)
    }
    r.attachments[key] = value
}