Replace lock on CacheStatusInfo with ConcurrentMap

Signed-off-by: Sebastian Schepens <sebastian.schepens@mercadolibre.com>

Author: sschepens

cache/src/main/java/io/envoyproxy/controlplane/cache/CacheStatusInfo.java

@@ -1,14 +1,10 @@
 package io.envoyproxy.controlplane.cache;
 
 import com.google.common.collect.ImmutableSet;
-import java.util.HashMap;
-import java.util.Map;
 import java.util.Set;
-import java.util.concurrent.locks.Lock;
-import java.util.concurrent.locks.ReadWriteLock;
-import java.util.concurrent.locks.ReentrantReadWriteLock;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
 import java.util.function.BiFunction;
-import javax.annotation.concurrent.GuardedBy;
 import javax.annotation.concurrent.ThreadSafe;
 
 /**
@@ -20,14 +16,7 @@ public class CacheStatusInfo<T> implements StatusInfo<T> {
 
   private final T nodeGroup;
 
-  @GuardedBy("lock")
-  private final Map<Long, Watch> watches = new HashMap<>();
-
-  private final ReadWriteLock lock = new ReentrantReadWriteLock();
-  private final Lock readLock = lock.readLock();
-  private final Lock writeLock = lock.writeLock();
-
-  @GuardedBy("lock")
+  private final ConcurrentMap<Long, Watch> watches = new ConcurrentHashMap<>();
   private long lastWatchRequestTime;
 
   public CacheStatusInfo(T nodeGroup) {
@@ -39,13 +28,7 @@ public CacheStatusInfo(T nodeGroup) {
    */
   @Override
   public long lastWatchRequestTime() {
-    readLock.lock();
-
-    try {
-      return lastWatchRequestTime;
-    } finally {
-      readLock.unlock();
-    }
+    return lastWatchRequestTime;
   }
 
   /**
@@ -61,13 +44,7 @@ public T nodeGroup() {
    */
   @Override
   public int numWatches() {
-    readLock.lock();
-
-    try {
-      return watches.size();
-    } finally {
-      readLock.unlock();
-    }
+    return watches.size();
   }
 
   /**
@@ -76,13 +53,7 @@ public int numWatches() {
    * @param watchId the ID for the watch that should be removed
    */
   public void removeWatch(long watchId) {
-    writeLock.lock();
-
-    try {
-      watches.remove(watchId);
-    } finally {
-      writeLock.unlock();
-    }
+    watches.remove(watchId);
   }
 
   /**
@@ -91,42 +62,24 @@ public void removeWatch(long watchId) {
    * @param lastWatchRequestTime the latest watch request timestamp
    */
   public void setLastWatchRequestTime(long lastWatchRequestTime) {
-    writeLock.lock();
-
-    try {
-      this.lastWatchRequestTime = lastWatchRequestTime;
-    } finally {
-      writeLock.unlock();
-    }
+    this.lastWatchRequestTime = lastWatchRequestTime;
   }
 
   /**
    * Adds the given watch to the tracked collection of watches.
    *
    * @param watchId the ID for the watch that should be added
-   * @param watch the watch that should be added
+   * @param watch   the watch that should be added
    */
   public void setWatch(long watchId, Watch watch) {
-    writeLock.lock();
-
-    try {
-      watches.put(watchId, watch);
-    } finally {
-      writeLock.unlock();
-    }
+    watches.put(watchId, watch);
   }
 
   /**
    * Returns the set of IDs for all watched currently being tracked.
    */
   public Set<Long> watchIds() {
-    readLock.lock();
-
-    try {
-      return ImmutableSet.copyOf(watches.keySet());
-    } finally {
-      readLock.unlock();
-    }
+    return ImmutableSet.copyOf(watches.keySet());
   }
 
   /**
@@ -136,12 +89,6 @@ public Set<Long> watchIds() {
    * @param filter the function to execute on each watch
    */
   public void watchesRemoveIf(BiFunction<Long, Watch, Boolean> filter) {
-    writeLock.lock();
-
-    try {
-      watches.entrySet().removeIf(entry -> filter.apply(entry.getKey(), entry.getValue()));
-    } finally {
-      writeLock.unlock();
-    }
+    watches.entrySet().removeIf(entry -> filter.apply(entry.getKey(), entry.getValue()));
   }
 }