Robert Munteanu created SLING-8759:
--------------------------------------
Summary: Replace the SlingAdaptable.adapterCache with a
ConcurrentMap
Key: SLING-8759
URL: https://issues.apache.org/jira/browse/SLING-8759
Project: Sling
Issue Type: Improvement
Components: API
Reporter: Robert Munteanu
Fix For: API 2.20.2
The SlingAdaptable.adapterCache is based on a HashMap guarded by a
{{synchronized}} block, with lazy initialisation. This looks like a perfect
scenario for {{ConcurrentMap.computeIfAbsent}}. The increased memory usage
should be measured though, as a simple implementation will not use lazy
initialisation, e.g.
{code}
diff --git a/src/main/java/org/apache/sling/api/adapter/SlingAdaptable.java
b/src/main/java/org/apache/sling/api/adapter/SlingAdaptable.java
index 5adf0ce..6bed14f 100644
--- a/src/main/java/org/apache/sling/api/adapter/SlingAdaptable.java
+++ b/src/main/java/org/apache/sling/api/adapter/SlingAdaptable.java
@@ -20,6 +20,8 @@ package org.apache.sling.api.adapter;
import java.util.HashMap;
import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
/**
* The <code>SlingAdaptable</code> class is an (abstract) default
implementation
@@ -74,7 +76,7 @@ public abstract class SlingAdaptable implements Adaptable {
* are intended to be short-lived to not hold on to objects and classes for
* too long.
*/
- private Map<Class<?>, Object> adaptersCache;
+ private ConcurrentMap<Class<?>, Object> adaptersCache = new
ConcurrentHashMap<Class<?>, Object>();
/**
* Calls into the registered {@link AdapterManager} to adapt this object to
@@ -94,22 +96,8 @@ public abstract class SlingAdaptable implements Adaptable {
*/
@SuppressWarnings("unchecked")
public <AdapterType> AdapterType adaptTo(Class<AdapterType> type) {
- AdapterType result = null;
- synchronized ( this ) {
- if ( adaptersCache != null ) {
- result = (AdapterType) adaptersCache.get(type);
- }
- if ( result == null ) {
- final AdapterManager mgr = ADAPTER_MANAGER;
- result = (mgr == null ? null : mgr.getAdapter(this, type));
- if ( result != null ) {
- if ( adaptersCache == null ) {
- adaptersCache = new HashMap<Class<?>, Object>();
- }
- adaptersCache.put(type, result);
- }
- }
- }
- return result;
+ return (AdapterType) adaptersCache.computeIfAbsent(type, (klazz) -> {
+ return ADAPTER_MANAGER.getAdapter(this, type);
+ });
}
}
{code}
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