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author | 2015-09-03 00:20:53 +0000 | |
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committer | 2015-09-03 09:04:47 +0000 | |
commit | 58109c3b23a87aa6f567486e8c267f98f0334449 (patch) | |
tree | 0216f5ecfa298262684cdb1ad58088806cf43698 /src/main/java/com/google/devtools/build/lib/concurrent/StripedKeyedLocker.java | |
parent | 18742ad31d29625f6dd65b697054c72153b62517 (diff) |
Add a new KeyedLocker, StripedKeyedLocker. This new implementation simply stores a striped set of reentrant locks.
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MOS_MIGRATED_REVID=102198213
Diffstat (limited to 'src/main/java/com/google/devtools/build/lib/concurrent/StripedKeyedLocker.java')
-rw-r--r-- | src/main/java/com/google/devtools/build/lib/concurrent/StripedKeyedLocker.java | 50 |
1 files changed, 50 insertions, 0 deletions
diff --git a/src/main/java/com/google/devtools/build/lib/concurrent/StripedKeyedLocker.java b/src/main/java/com/google/devtools/build/lib/concurrent/StripedKeyedLocker.java new file mode 100644 index 0000000000..505ea6c195 --- /dev/null +++ b/src/main/java/com/google/devtools/build/lib/concurrent/StripedKeyedLocker.java @@ -0,0 +1,50 @@ +// Copyright 2015 Google Inc. All rights reserved. +// +// 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 com.google.devtools.build.lib.concurrent; + +import com.google.common.util.concurrent.Striped; + +import java.util.concurrent.atomic.AtomicBoolean; +import java.util.concurrent.locks.Lock; + +/** + * An implementation of {@link KeyedLocker} backed by a {@link Striped}. + */ +public class StripedKeyedLocker<K> implements KeyedLocker<K> { + + private final Striped<Lock> locks; + + public StripedKeyedLocker(int stripes) { + locks = Striped.lock(stripes); + } + + @Override + public AutoUnlocker lock(final K key) { + final Lock lock = locks.get(key); + lock.lock(); + return new AutoUnlocker() { + private final AtomicBoolean closeCalled = new AtomicBoolean(false); + + @Override + public void close() { + if (closeCalled.getAndSet(true)) { + String msg = String.format("For key %s, 'close' can be called at most once per " + + "AutoUnlocker instance", key); + throw new IllegalUnlockException(msg); + } + lock.unlock(); + } + }; + } +} |