Replace synchronized with ReentrantLock

src/main/java/cc/ryanc/halo/cache/InMemoryCacheStore.java

@@ -5,6 +5,8 @@ import org.springframework.util.Assert;
 
 import java.util.Optional;
 import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReentrantLock;
 
 /**
  * In-memory cache store.
@@ -19,6 +21,11 @@ public class InMemoryCacheStore extends StringCacheStore {
      */
     private final static ConcurrentHashMap<String, CacheWrapper<String>> cacheContainer = new ConcurrentHashMap<>();
 
+    /**
+     * Lock.
+     */
+    private Lock lock = new ReentrantLock();
+
     @Override
     Optional<CacheWrapper<String>> getInternal(String key) {
         Assert.hasText(key, "Cache key must not be blank");
@@ -38,12 +45,14 @@ public class InMemoryCacheStore extends StringCacheStore {
     }
 
     @Override
-    synchronized Boolean putInternalIfAbsent(String key, CacheWrapper<String> cacheWrapper) {
+    Boolean putInternalIfAbsent(String key, CacheWrapper<String> cacheWrapper) {
         Assert.hasText(key, "Cache key must not be blank");
         Assert.notNull(cacheWrapper, "Cache wrapper must not be null");
 
         log.debug("Preparing to put key: [{}], value: [{}]", key, cacheWrapper);
 
+        try {
+            lock.lock();
             // Get the value before
             Optional<String> valueOptional = get(key);
 
@@ -54,10 +63,11 @@ public class InMemoryCacheStore extends StringCacheStore {
 
             // Put the cache wrapper
             putInternal(key, cacheWrapper);
-
             log.debug("Put successfully");
-
             return true;
+        } finally {
+            lock.unlock();
+        }
     }
 
     @Override