From ff6a2d014aae477eba76494815f700eb64349c9c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Torkel=20=C3=96degaard?= <torkel.odegaard@gmail.com>
Date: Mon, 1 Dec 2014 08:56:03 -0800
Subject: [PATCH] Refactored command/query interface

---
 pkg/bus/bus.go      | 28 +++++++++++++++++-----------
 pkg/bus/bus_test.go | 12 ++++++------
 2 files changed, 23 insertions(+), 17 deletions(-)

diff --git a/pkg/bus/bus.go b/pkg/bus/bus.go
index 5dee1d024ab..ceca947959f 100644
--- a/pkg/bus/bus.go
+++ b/pkg/bus/bus.go
@@ -9,19 +9,26 @@ import (
 type QueryHandler interface{}
 type Query interface{}
 
-var (
-	handlerIndex map[string]QueryHandler
-)
-
-func InitBus() {
-	handlerIndex = make(map[string]QueryHandler)
+type Bus interface {
+	SendQuery(query Query) error
+	AddQueryHandler(handler QueryHandler)
 }
 
-func SendQuery(query interface{}) error {
+type InProcBus struct {
+	handlerIndex map[string]QueryHandler
+}
+
+func New() Bus {
+	bus := &InProcBus{}
+	bus.handlerIndex = make(map[string]QueryHandler)
+	return bus
+}
+
+func (b *InProcBus) SendQuery(query Query) error {
 	var queryName = reflect.TypeOf(query).Elem().Name()
 	fmt.Printf("sending query for type: %v\n", queryName)
 
-	var handler = handlerIndex[queryName]
+	var handler = b.handlerIndex[queryName]
 	if handler == nil {
 		return errors.New("handler not found")
 
@@ -38,10 +45,9 @@ func SendQuery(query interface{}) error {
 	}
 }
 
-func AddQueryHandler(handler QueryHandler) {
+func (b *InProcBus) AddQueryHandler(handler QueryHandler) {
 	handlerType := reflect.TypeOf(handler)
 	queryTypeName := handlerType.In(0).Elem().Name()
 	fmt.Printf("QueryType %v\n", queryTypeName)
-	handlerIndex[queryTypeName] = handler
-	//fmt.Printf("Adding handler for type: %v\n", queryTypeName)
+	b.handlerIndex[queryTypeName] = handler
 }
diff --git a/pkg/bus/bus_test.go b/pkg/bus/bus_test.go
index 2840b04366d..457aa48188b 100644
--- a/pkg/bus/bus_test.go
+++ b/pkg/bus/bus_test.go
@@ -11,13 +11,13 @@ type TestQuery struct {
 }
 
 func TestHandlerReturnsError(t *testing.T) {
-	InitBus()
+	bus := New()
 
-	AddQueryHandler(func(query *TestQuery) error {
+	bus.AddQueryHandler(func(query *TestQuery) error {
 		return errors.New("handler error")
 	})
 
-	err := SendQuery(&TestQuery{})
+	err := bus.SendQuery(&TestQuery{})
 
 	if err == nil {
 		t.Fatal("Send query failed %v", err)
@@ -27,15 +27,15 @@ func TestHandlerReturnsError(t *testing.T) {
 }
 
 func TestHandlerReturn(t *testing.T) {
-	InitBus()
+	bus := New()
 
-	AddQueryHandler(func(q *TestQuery) error {
+	bus.AddQueryHandler(func(q *TestQuery) error {
 		q.Resp = "hello from handler"
 		return nil
 	})
 
 	query := &TestQuery{}
-	err := SendQuery(query)
+	err := bus.SendQuery(query)
 
 	if err != nil {
 		t.Fatal("Send query failed %v", err)