Use inner classes and make an Session interface implemented by a Cache.

3 files changed, 27 insertions, 34 deletions

diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/persistence/CuratorCache.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/persistence/CuratorCache.java
deleted file mode 100644
index 674aa1b8f22..00000000000
--- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/persistence/CuratorCache.java
+++ /dev/null
@@ -1,14 +0,0 @@
-package com.yahoo.vespa.hosted.provision.persistence;
-
-import com.yahoo.path.Path;
-
-import java.util.List;
-import java.util.Optional;
-
-public abstract class CuratorCache {
-
-    public abstract List<String> getChildren(Path path);
-
-    public abstract Optional<byte[]> getData(Path path);
-
-}
\ No newline at end of file
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/persistence/CuratorDatabase.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/persistence/CuratorDatabase.java
index 3da54a3db8c..8f4788a9206 100644
--- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/persistence/CuratorDatabase.java
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/persistence/CuratorDatabase.java
@@ -36,7 +36,7 @@ public class CuratorDatabase {
     private final CuratorCounter changeGenerationCounter;
 
     /** A partial cache of the Curator database, which is only valid if generations match */
-    private final AtomicReference<CuratorDatabaseCache> cache = new AtomicReference<>();
+    private final AtomicReference<Cache> cache = new AtomicReference<>();
 
     /** Whether we should return data from the cache or always read fro ZooKeeper */
     private final boolean useCache;
@@ -125,7 +125,7 @@ public class CuratorDatabase {
     Optional<byte[]> getData(Path path) { return getSession().getData(path); }
 
     /** Invalidates the current cache if outdated. */
-    CuratorCache getSession() {
+    Session getSession() {
         if (changeGenerationCounter.get() != cache.get().generation)
             synchronized (cacheCreationLock) {
                 while (changeGenerationCounter.get() != cache.get().generation)
@@ -136,8 +136,8 @@ public class CuratorDatabase {
     }
 
     /** Caches must only be instantiated using this method */
-    private CuratorDatabaseCache newCache(long generation) {
-        return useCache ? new CuratorDatabaseCache(generation, curator) : new DeactivatedCache(generation, curator);
+    private Cache newCache(long generation) {
+        return useCache ? new Cache(generation, curator) : new NoCache(generation, curator);
     }
 
     /**
@@ -145,10 +145,10 @@ public class CuratorDatabase {
      * This is merely a recording of what Curator returned at various points in time when 
      * it had the counter at this generation.
      */
-    private static class CuratorDatabaseCache extends CuratorCache {
+    private static class Cache implements Session {
 
         private final long generation;
-        
+
         /** The curator instance used to fetch missing data */
         protected final Curator curator;
 
@@ -159,23 +159,17 @@ public class CuratorDatabase {
         private final Map<Path, Optional<byte[]>> data = new ConcurrentHashMap<>();
 
         /** Create an empty snapshot at a given generation (as an empty snapshot is a valid partial snapshot) */
-        private CuratorDatabaseCache(long generation, Curator curator) {
+        private Cache(long generation, Curator curator) {
             this.generation = generation;
             this.curator = curator;
         }
 
-        public long generation() { return generation; }
-
-        /**
-         * Returns the children of this path, which may be empty.
-         */
+        @Override
         public List<String> getChildren(Path path) { 
             return children.computeIfAbsent(path, key -> ImmutableList.copyOf(curator.getChildren(path)));
         }
 
-        /**
-         * Returns the a copy of the content of this child - which may be empty.
-         */
+        @Override
         public Optional<byte[]> getData(Path path) {
             return data.computeIfAbsent(path, key -> curator.getData(path)).map(data -> Arrays.copyOf(data, data.length));
         }
@@ -183,9 +177,9 @@ public class CuratorDatabase {
     }
 
     /** An implementation of the curator database cache which does no caching */
-    private static class DeactivatedCache extends CuratorDatabaseCache {
-        
-        private DeactivatedCache(long generation, Curator curator) { super(generation, curator); }
+    private static class NoCache extends Cache {
+
+        private NoCache(long generation, Curator curator) { super(generation, curator); }
 
         @Override
         public List<String> getChildren(Path path) { return curator.getChildren(path); }
@@ -195,4 +189,17 @@ public class CuratorDatabase {
 
     }
 
+    interface Session {
+
+        /**
+         * Returns the children of this path, which may be empty.
+         */
+        List<String> getChildren(Path path);
+
+        /**
+         * Returns the a copy of the content of this child - which may be empty.
+         */
+        Optional<byte[]> getData(Path path);
+
+    }
 }
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/persistence/CuratorDatabaseClient.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/persistence/CuratorDatabaseClient.java
index 049f242ed2e..a2869a82654 100644
--- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/persistence/CuratorDatabaseClient.java
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/persistence/CuratorDatabaseClient.java
@@ -258,7 +258,7 @@ public class CuratorDatabaseClient {
         List<Node> nodes = new ArrayList<>();
         if (states.length == 0)
             states = Node.State.values();
-        CuratorCache session = curatorDatabase.getSession();
+        CuratorDatabase.Session session = curatorDatabase.getSession();
         for (Node.State state : states) {
             for (String hostname : session.getChildren(toPath(state))) {
                 Optional<Node> node = getNode(session, hostname, state);
@@ -282,7 +282,7 @@ public class CuratorDatabaseClient {
      * Returns a particular node, or empty if this noe is not in any of the given states.
      * If no states are given this returns the node if it is present in any state.
      */
-    public Optional<Node> getNode(CuratorCache session, String hostname, Node.State ... states) {
+    public Optional<Node> getNode(CuratorDatabase.Session session, String hostname, Node.State ... states) {
         if (states.length == 0)
             states = Node.State.values();
         for (Node.State state : states) {