org.apache.hadoop.hbase.procedure2

类 LockAndQueue

java.lang.Object

java.util.AbstractCollection<E>

java.util.ArrayDeque<Procedure>

org.apache.hadoop.hbase.procedure2.ProcedureDeque

org.apache.hadoop.hbase.procedure2.LockAndQueue

所有已实现的接口:

Serializable, Cloneable, Iterable<Procedure>, Collection<Procedure>, Deque<Procedure>, Queue<Procedure>, LockStatus

@InterfaceAudience.Private
public class LockAndQueue
extends ProcedureDeque
implements LockStatus

Locking for mutual exclusion between procedures. Used only by procedure framework internally. LockAndQueue has two purposes:

1. Acquire/release exclusive/shared locks.
2. Maintains a list of procedures waiting on this lock. LockAndQueue extends ProcedureDeque class. Blocked Procedures are added to our super Deque. Using inheritance over composition to keep the Deque of waiting Procedures is unusual, but we do it this way because in certain cases, there will be millions of regions. This layout uses less memory.

NOT thread-safe. Needs external concurrency control: e.g. uses in MasterProcedureScheduler are guarded by schedLock().
There is no need of 'volatile' keyword for member variables because of memory synchronization guarantees of locks (see 'Memory Synchronization', http://docs.oracle.com/javase/8/docs/api/java/util/concurrent/locks/Lock.html)
We do not implement Lock interface because we need exclusive and shared locking, and also because try-lock functions require procedure id.
We do not use ReentrantReadWriteLock directly because of its high memory overhead.

另请参阅:

序列化表格

构造器概要

构造器

构造器和说明
LockAndQueue()

方法概要

限定符和类型	方法和说明
Procedure<?>	getExclusiveLockOwnerProcedure()
long	getExclusiveLockProcIdOwner()
int	getSharedLockCount()
boolean	hasExclusiveLock()
boolean	hasLockAccess(Procedure proc)
boolean	hasParentLock(Procedure proc)
boolean	isLocked()
boolean	isLockOwner(long procId)
boolean	releaseExclusiveLock(Procedure proc)
boolean	releaseSharedLock()
String	toString()
boolean	tryExclusiveLock(Procedure proc)
boolean	trySharedLock()

从类继承的方法 java.util.ArrayDeque

add, addFirst, addLast, clear, clone, contains, descendingIterator, element, getFirst, getLast, isEmpty, iterator, offer, offerFirst, offerLast, peek, peekFirst, peekLast, poll, pollFirst, pollLast, pop, push, remove, remove, removeFirst, removeFirstOccurrence, removeLast, removeLastOccurrence, size, spliterator, toArray, toArray

从类继承的方法 java.util.AbstractCollection

addAll, containsAll, removeAll, retainAll

从类继承的方法 java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

从接口继承的方法 java.util.Collection

addAll, containsAll, equals, hashCode, parallelStream, removeAll, removeIf, retainAll, stream

从接口继承的方法 java.lang.Iterable

forEach

构造器详细资料

LockAndQueue

public LockAndQueue()

方法详细资料

isLocked

public boolean isLocked()

指定者:

isLocked 在接口中 LockStatus

hasExclusiveLock

public boolean hasExclusiveLock()

指定者:

hasExclusiveLock 在接口中 LockStatus

isLockOwner

public boolean isLockOwner(long procId)

指定者:

isLockOwner 在接口中 LockStatus

hasParentLock

public boolean hasParentLock(Procedure proc)

指定者:

hasParentLock 在接口中 LockStatus

hasLockAccess

public boolean hasLockAccess(Procedure proc)

指定者:

hasLockAccess 在接口中 LockStatus

getExclusiveLockOwnerProcedure

public Procedure<?> getExclusiveLockOwnerProcedure()

指定者:

getExclusiveLockOwnerProcedure 在接口中 LockStatus

getExclusiveLockProcIdOwner

public long getExclusiveLockProcIdOwner()

指定者:

getExclusiveLockProcIdOwner 在接口中 LockStatus

getSharedLockCount

public int getSharedLockCount()

指定者:

getSharedLockCount 在接口中 LockStatus

trySharedLock

public boolean trySharedLock()

releaseSharedLock

public boolean releaseSharedLock()

tryExclusiveLock

public boolean tryExclusiveLock(Procedure proc)

releaseExclusiveLock

public boolean releaseExclusiveLock(Procedure proc)

返回:

True if we released a lock.

toString

public String toString()

覆盖:

toString 在类中 AbstractCollection<Procedure>