Examples of org.menagerie.locks.ReentrantZkLock$LockHolder

org.menagerie.locks.ReentrantZkLock

A ZooKeeper-based implementation of a fair, Reentrant mutex Lock.

A {@code ReentrantZkLock} is owned by the party (both the current thread and the running ZooKeeper client)which has last successfully locked it, but has not yet unlocked it. Parties invoking {@code lock} will return,successfully acquiring the lock, whenever the lock is not owned by another party. All methods will return immediate success if the current party is the lock owner. This can be checked by {@link #hasLock()}.

Note that this implementation is fully fair; multiple concurrent requests by different parties will be granted in order, where the ordering is determined by the ZooKeeper server.

This lock supports {@code Integer.MAX_VALUE} repeated locks by the same thread. Attempts to exceed this resultin overflows which can create an improper lock state. @author Scott Fines @version 1.0 @see java.util.concurrent.locks.ReentrantLock @deprecated Use {@link Locksmith.reentrantLock} factories to create a different (internal) lock instance instead.

        segmentShift = 32 - sshift;
        segmentMask = ssize - 1;
        this.segments = ZkSegment.newArray(ssize);


        //need to build the map in a single, synchronized activity across all members
        Lock mapLock = new ReentrantZkLock(mapNode,zkSessionManager,privileges);
        mapLock.lock();
        try{
            //need to read the data out of zookeeper
            ZooKeeper zk = zkSessionManager.getZooKeeper();
            for(int i=0;i< segments.length;i++){
                try {
                    //attach the first segments to any segments which are already created
                    List<String> zkBuckets = ZkUtils.filterByPrefix(zk.getChildren(mapNode,false),"bucket");
                    ZkUtils.sortBySequence(zkBuckets,'-');
                    int numBucketsBuilt = 0;
                    for(int bucketIndex=0;bucketIndex<zkBuckets.size()&&bucketIndex< segments.length;bucketIndex++){
                        numBucketsBuilt++;
                        segments[bucketIndex] = new ZkSegment<K,V>(mapNode+"/"+zkBuckets.get(bucketIndex),
                                serializer,zkSessionManager,privileges);
                    }


                    //create any additional segments as needed
                    while(numBucketsBuilt< segments.length){
                        String bucketNode = ZkUtils.safeCreate(zk, mapNode + "/bucket-",
                                new byte[]{}, privileges, CreateMode.PERSISTENT_SEQUENTIAL);
                        segments[numBucketsBuilt] = new ZkSegment<K,V>(bucketNode,
                                serializer,zkSessionManager,privileges);
                        numBucketsBuilt++;
                    }
                } catch (KeeperException e) {
                    throw new RuntimeException(e);
                } catch (InterruptedException e) {
                    throw new RuntimeException(e);
                }
            }
        }finally{
            mapLock.unlock();
        }
    }

Examples of org.menagerie.locks.ReentrantZkLock$LockHolder

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