1 files changed, 44 insertions, 0 deletions
diff --git a/nouveau/src/main/java/org/apache/couchdb/nouveau/core/StripedLock.java b/nouveau/src/main/java/org/apache/couchdb/nouveau/core/StripedLock.java
new file mode 100644
index 000000000..ad2948ee7
--- /dev/null
+++ b/nouveau/src/main/java/org/apache/couchdb/nouveau/core/StripedLock.java
@@ -0,0 +1,44 @@
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package org.apache.couchdb.nouveau.core;
+
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReadWriteLock;
+import java.util.concurrent.locks.ReentrantReadWriteLock;
+
+final class StripedLock<K> {
+
+    private final ReadWriteLock[] locks;
+
+    public StripedLock(
+            final int lockCount) {
+        this.locks = new ReadWriteLock[lockCount];
+        for (int i = 0; i < locks.length; i++) {
+            this.locks[i] = new ReentrantReadWriteLock();
+        }
+    }
+
+    public Lock readLock(final K key) {
+        return readWriteLock(key).readLock();
+    }
+
+    public Lock writeLock(final K key) {
+        return readWriteLock(key).writeLock();
+    }
+
+    private ReadWriteLock readWriteLock(final K key) {
+        return locks[Math.floorMod(key.hashCode(), locks.length)];
+    }
+
+}