From 7316f99bd9594707f19ba285574adb3038e93fda Mon Sep 17 00:00:00 2001
From: Karl Seguin <karl@openmymind.io>
Date: Thu, 13 Nov 2014 22:23:52 +0700
Subject: [PATCH] replace on layeredcache

---
 layeredbucket.go     | 10 ++++++++++
 layeredcache.go      |  4 ++++
 layeredcache_test.go | 16 ++++++++++++----
 3 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/layeredbucket.go b/layeredbucket.go
index 6a443bf..0934437 100644
--- a/layeredbucket.go
+++ b/layeredbucket.go
@@ -35,6 +35,16 @@ func (b *LayeredBucket) set(primary, secondary string, value interface{}, durati
 	return item, new
 }
 
+func (b *LayeredBucket) replace(primary, secondary string, value interface{}) bool {
+	b.Lock()
+	bucket, exists := b.buckets[primary]
+	b.Unlock()
+	if exists == false {
+		return false
+	}
+	return bucket.replace(secondary, value)
+}
+
 func (b *LayeredBucket) delete(primary, secondary string) *Item {
 	b.RLock()
 	bucket, exists := b.buckets[primary]
diff --git a/layeredcache.go b/layeredcache.go
index 0b04062..b04be74 100644
--- a/layeredcache.go
+++ b/layeredcache.go
@@ -65,6 +65,10 @@ func (c *LayeredCache) Set(primary, secondary string, value interface{}, duratio
 	}
 }
 
+func (c *LayeredCache) Replace(primary, secondary string, value interface{}) bool {
+	return c.bucket(primary).replace(primary, secondary, value)
+}
+
 func (c *LayeredCache) Fetch(primary, secondary string, duration time.Duration, fetch func() (interface{}, error)) (interface{}, error) {
 	item := c.Get(primary, secondary)
 	if item != nil {
diff --git a/layeredcache_test.go b/layeredcache_test.go
index a576d10..32162fb 100644
--- a/layeredcache_test.go
+++ b/layeredcache_test.go
@@ -39,6 +39,18 @@ func (l *LayeredCacheTests) SetsMultipleValueWithinTheSameLayer() {
 	Expect(cache.Get("baron", "friend")).To.Equal(nil)
 }
 
+func (l *LayeredCacheTests) ReplaceDoesNothingIfKeyDoesNotExist() {
+	cache := newLayered()
+	Expect(cache.Replace("spice", "flow", "value-a")).To.Equal(false)
+}
+
+func (l *LayeredCacheTests) ReplaceUpdatesTheValue() {
+	cache := newLayered()
+	cache.Set("spice", "flow", "value-a", time.Minute)
+	Expect(cache.Replace("spice", "flow", "value-b")).To.Equal(true)
+	Expect(cache.Get("spice", "flow").Value().(string)).To.Equal("value-b")
+}
+
 func (l *LayeredCacheTests) DeletesAValue() {
 	cache := newLayered()
 	cache.Set("spice", "flow", "value-a", time.Minute)
@@ -125,10 +137,6 @@ func (c *LayeredCacheTests) RemovesOldestItemWhenFull() {
 	Expect(cache.Get("xx", "b").Value()).To.Equal(9001)
 }
 
-// func (c *LayeredCacheTests) GetsAnExpiredIten() {
-
-// }
-
 func newLayered() *LayeredCache {
 	return Layered(Configure())
 }