diff options
Diffstat (limited to 'nouveau/src/main/java/org/apache/couchdb/nouveau/core/StripedLock.java')
-rw-r--r-- | nouveau/src/main/java/org/apache/couchdb/nouveau/core/StripedLock.java | 44 |
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)]; + } + +} |