From 87bcfec6ede1da7bc2bdc906899ff94ac0fb6aeb Mon Sep 17 00:00:00 2001
From: Steve Draper <sdraper@cognitivescale.com>
Date: Fri, 28 Apr 2017 11:35:57 -0500
Subject: [PATCH] Added pre-warm mechanism for locally cached maps

---
 .../java/org/redisson/RedissonLocalCachedMap.java  | 14 +++++++++++++-
 .../java/org/redisson/api/RLocalCachedMap.java     |  7 ++++++-
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/redisson/src/main/java/org/redisson/RedissonLocalCachedMap.java b/redisson/src/main/java/org/redisson/RedissonLocalCachedMap.java
index d81febe2e..efb981356 100644
--- a/redisson/src/main/java/org/redisson/RedissonLocalCachedMap.java
+++ b/redisson/src/main/java/org/redisson/RedissonLocalCachedMap.java
@@ -1084,7 +1084,19 @@ public class RedissonLocalCachedMap<K, V> extends RedissonMap<K, V> implements R
         
         return promise;
     }
-    
+
+    @Override
+    public void preloadCache() {
+        //  Best-attempt warmup - just enumerate as an uncached map (super) and
+        //  add anything found into the cache.  This does not guarantee to find
+        //  entries added during the warmUp, but statistically the cache will have
+        //  few misses after this process
+        for(Entry<K,V> entry : super.entrySet()) {
+            CacheKey cacheKey = toCacheKey(entry.getKey());
+            cache.put(cacheKey, new CacheValue(entry.getKey(), entry.getValue()));
+        }
+    }
+
     @Override
     public RFuture<Set<Entry<K, V>>> readAllEntrySetAsync() {
         final Set<Entry<K, V>> result = new HashSet<Entry<K, V>>();
diff --git a/redisson/src/main/java/org/redisson/api/RLocalCachedMap.java b/redisson/src/main/java/org/redisson/api/RLocalCachedMap.java
index a7f7ed9c6..43223cd1f 100644
--- a/redisson/src/main/java/org/redisson/api/RLocalCachedMap.java
+++ b/redisson/src/main/java/org/redisson/api/RLocalCachedMap.java
@@ -27,5 +27,10 @@ package org.redisson.api;
  * @param <V> map value
  */
 public interface RLocalCachedMap<K, V> extends RMap<K, V>, RDestroyable {
-
+    /**
+     * Pre-warm the cached values.  Not guaranteed to load ALL values, but statistically
+     * will preload approximately all (all if no concurrent mutating activity)
+     * Intended for use with no-eviction caches where entire maps are locally cached
+     */
+    public void preloadCache();
 }