ONOS-2429: Support for a relaxed read consistency mode in ConsistentMap
Change-Id: I7866d8d15de369fd23e482d66cc1c918c033f169
diff --git a/core/store/dist/src/main/java/org/onosproject/store/consistent/impl/AsyncCachingConsistentMap.java b/core/store/dist/src/main/java/org/onosproject/store/consistent/impl/AsyncCachingConsistentMap.java
new file mode 100644
index 0000000..bbc703d
--- /dev/null
+++ b/core/store/dist/src/main/java/org/onosproject/store/consistent/impl/AsyncCachingConsistentMap.java
@@ -0,0 +1,56 @@
+package org.onosproject.store.consistent.impl;
+
+import java.util.concurrent.CompletableFuture;
+
+import org.onosproject.core.ApplicationId;
+import org.onosproject.store.service.Serializer;
+import org.onosproject.store.service.Versioned;
+
+import com.google.common.cache.CacheBuilder;
+import com.google.common.cache.CacheLoader;
+import com.google.common.cache.LoadingCache;
+
+/**
+ * Extension of DefaultAsyncConsistentMap that provides a weaker read consistency
+ * guarantee in return for better read performance.
+ *
+ * @param <K> key type
+ * @param <V> value type
+ */
+public class AsyncCachingConsistentMap<K, V> extends DefaultAsyncConsistentMap<K, V> {
+
+ private final LoadingCache<K, CompletableFuture<Versioned<V>>> cache =
+ CacheBuilder.newBuilder()
+ .maximumSize(10000) // TODO: make configurable
+ .build(new CacheLoader<K, CompletableFuture<Versioned<V>>>() {
+ @Override
+ public CompletableFuture<Versioned<V>> load(K key)
+ throws Exception {
+ return AsyncCachingConsistentMap.super.get(key);
+ }
+ });
+
+ public AsyncCachingConsistentMap(String name,
+ ApplicationId applicationId,
+ Database database,
+ Serializer serializer,
+ boolean readOnly,
+ boolean purgeOnUninstall,
+ boolean meteringEnabled) {
+ super(name, applicationId, database, serializer, readOnly, purgeOnUninstall, meteringEnabled);
+ addListener(event -> cache.invalidate(event.key()));
+ }
+
+ @Override
+ public CompletableFuture<Versioned<V>> get(K key) {
+ CompletableFuture<Versioned<V>> cachedValue = cache.getIfPresent(key);
+ if (cachedValue != null) {
+ if (cachedValue.isCompletedExceptionally()) {
+ cache.invalidate(key);
+ } else {
+ return cachedValue;
+ }
+ }
+ return cache.getUnchecked(key);
+ }
+}
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