From b07f4a0c78dd23641ed3e995b8cc3dd8c4b107e5 Mon Sep 17 00:00:00 2001
From: Tamas Cservenak <tamas@cservenak.net>
Date: Fri, 8 Dec 2023 17:26:00 +0100
Subject: [PATCH 1/3] [MRESOLVER-450] Enhance RepositoryCache

Enhance RepositoryCache

---

https://issues.apache.org/jira/browse/MRESOLVER-450
---
 .../org/eclipse/aether/DefaultRepositoryCache.java   |  8 +++++++-
 .../java/org/eclipse/aether/RepositoryCache.java     | 12 ++++++++++++
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/maven-resolver-api/src/main/java/org/eclipse/aether/DefaultRepositoryCache.java b/maven-resolver-api/src/main/java/org/eclipse/aether/DefaultRepositoryCache.java
index de8c4dc9a..d7c62c475 100644
--- a/maven-resolver-api/src/main/java/org/eclipse/aether/DefaultRepositoryCache.java
+++ b/maven-resolver-api/src/main/java/org/eclipse/aether/DefaultRepositoryCache.java
@@ -20,6 +20,7 @@
 
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
+import java.util.function.Supplier;
 
 /**
  * A simplistic repository cache backed by a thread-safe map. The simplistic nature of this cache makes it only suitable
@@ -27,7 +28,7 @@
  */
 public final class DefaultRepositoryCache implements RepositoryCache {
 
-    private final Map<Object, Object> cache = new ConcurrentHashMap<>(256);
+    private final ConcurrentHashMap<Object, Object> cache = new ConcurrentHashMap<>(256);
 
     public Object get(RepositorySystemSession session, Object key) {
         return cache.get(key);
@@ -40,4 +41,9 @@ public void put(RepositorySystemSession session, Object key, Object data) {
             cache.remove(key);
         }
     }
+
+    @Override
+    public Object computeIfAbsent(RepositorySystemSession session, Object key, Supplier<Object> supplier) {
+        return cache.computeIfAbsent(key, k -> supplier.get());
+    }
 }
diff --git a/maven-resolver-api/src/main/java/org/eclipse/aether/RepositoryCache.java b/maven-resolver-api/src/main/java/org/eclipse/aether/RepositoryCache.java
index 9bf6268f0..ef74e47a7 100644
--- a/maven-resolver-api/src/main/java/org/eclipse/aether/RepositoryCache.java
+++ b/maven-resolver-api/src/main/java/org/eclipse/aether/RepositoryCache.java
@@ -18,6 +18,8 @@
  */
 package org.eclipse.aether;
 
+import java.util.function.Supplier;
+
 /**
  * Caches auxiliary data used during repository access like already processed metadata. The data in the cache is meant
  * for exclusive consumption by the repository system and is opaque to the cache implementation. <strong>Note:</strong>
@@ -53,4 +55,14 @@ public interface RepositoryCache {
      * @return The requested data or {@code null} if none was present in the cache.
      */
     Object get(RepositorySystemSession session, Object key);
+
+    /**
+     * Retrieve or compute the data associated with the specified key.
+     *
+     * @param key The key for which to retrieve the session data, must not be {@code null}.
+     * @param supplier The supplier will compute the new value, must not be {@code null}.
+     * @return The cache data associated with the key.
+     * @since 2.0.0
+     */
+    Object computeIfAbsent(RepositorySystemSession session, Object key, Supplier<Object> supplier);
 }

From cdc6c925f5f60b71e593b3e24addef79d19093b6 Mon Sep 17 00:00:00 2001
From: Tamas Cservenak <tamas@cservenak.net>
Date: Fri, 8 Dec 2023 18:07:09 +0100
Subject: [PATCH 2/3] Reformat

---
 .../src/main/java/org/eclipse/aether/DefaultRepositoryCache.java | 1 -
 1 file changed, 1 deletion(-)

diff --git a/maven-resolver-api/src/main/java/org/eclipse/aether/DefaultRepositoryCache.java b/maven-resolver-api/src/main/java/org/eclipse/aether/DefaultRepositoryCache.java
index d7c62c475..e0f6d5052 100644
--- a/maven-resolver-api/src/main/java/org/eclipse/aether/DefaultRepositoryCache.java
+++ b/maven-resolver-api/src/main/java/org/eclipse/aether/DefaultRepositoryCache.java
@@ -18,7 +18,6 @@
  */
 package org.eclipse.aether;
 
-import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.function.Supplier;
 

From b7a6462789fc3cf2d9532780d88ef9279a69a5ee Mon Sep 17 00:00:00 2001
From: Tamas Cservenak <tamas@cservenak.net>
Date: Fri, 8 Dec 2023 18:14:05 +0100
Subject: [PATCH 3/3] This iface is safe as data

But lacked warning to not implement it
---
 .../src/main/java/org/eclipse/aether/RepositoryCache.java       | 2 ++
 pom.xml                                                         | 1 +
 2 files changed, 3 insertions(+)

diff --git a/maven-resolver-api/src/main/java/org/eclipse/aether/RepositoryCache.java b/maven-resolver-api/src/main/java/org/eclipse/aether/RepositoryCache.java
index ef74e47a7..565048c8e 100644
--- a/maven-resolver-api/src/main/java/org/eclipse/aether/RepositoryCache.java
+++ b/maven-resolver-api/src/main/java/org/eclipse/aether/RepositoryCache.java
@@ -26,6 +26,8 @@
  * Actual cache implementations must be thread-safe.
  *
  * @see RepositorySystemSession#getCache()
+ * @noimplement This interface is not intended to be implemented by clients.
+ * @noextend This interface is not intended to be extended by clients.
  */
 public interface RepositoryCache {
 
diff --git a/pom.xml b/pom.xml
index 178a31526..602423fc2 100644
--- a/pom.xml
+++ b/pom.xml
@@ -299,6 +299,7 @@
               <configuration>
                 <parameter>
                   <excludes>
+                    <exclude>org.eclipse.aether.RepositoryCache</exclude>
                     <exclude>org.eclipse.aether.RepositoryListener</exclude>
                     <exclude>org.eclipse.aether.RepositorySystem</exclude>
                     <exclude>org.eclipse.aether.RepositorySystemSession</exclude>