org.apache.hadoop.hbase.master.locking

Class LockManager.MasterLock

java.lang.Object

org.apache.hadoop.hbase.master.locking.LockManager.MasterLock

Enclosing class:

LockManager

public class LockManager.MasterLock
extends Object

Locks on namespace/table/regions. Underneath, uses procedure framework and queues a LockProcedure which waits in a queue until scheduled. Use this lock instead LockManager.remoteLocks() for MASTER ONLY operations for two advantages: - no need of polling on LockProcedure to check if lock was acquired. - Generous timeout for lock preemption (default 10 min), no need to spawn thread for heartbeats. (timeout configuration LockProcedure.DEFAULT_LOCAL_MASTER_LOCKS_TIMEOUT_MS).

Field Summary

Fields

Modifier and Type	Field and Description
private String	description
private String	namespace
private LockProcedure	proc
private RegionInfo[]	regionInfos
private TableName	tableName
private LockType	type

Constructor Summary

Constructors

Constructor and Description
MasterLock(RegionInfo[] regionInfos, String description)
MasterLock(String namespace, LockType type, String description)
MasterLock(TableName tableName, LockType type, String description)

Method Summary

Modifier and Type	Method and Description
boolean	acquire() Acquire the lock, waiting indefinitely until the lock is released or the thread is interrupted.
(package private) LockProcedure	getProc()
void	release() Release the lock.
String	toString()
boolean	tryAcquire(long timeoutMs) Acquire the lock within a wait time.

Methods inherited from class java.lang.Object

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

Field Detail

namespace

private final String namespace

tableName

private final TableName tableName

regionInfos

private final RegionInfo[] regionInfos

type

private final LockType type

description

private final String description

proc

private LockProcedure proc

Constructor Detail

MasterLock

public MasterLock(String namespace,
                  LockType type,
                  String description)

MasterLock

public MasterLock(TableName tableName,
                  LockType type,
                  String description)

MasterLock

public MasterLock(RegionInfo[] regionInfos,
                  String description)

Method Detail

acquire

public boolean acquire()
                throws InterruptedException

Acquire the lock, waiting indefinitely until the lock is released or the thread is interrupted.

Throws:

InterruptedException - If current thread is interrupted while waiting for the lock

tryAcquire

public boolean tryAcquire(long timeoutMs)
                   throws InterruptedException

Acquire the lock within a wait time.

Parameters:

timeoutMs - The maximum time (in milliseconds) to wait for the lock, 0 to wait indefinitely

Returns:

True if the lock was acquired, false if waiting time elapsed before the lock was acquired

Throws:

InterruptedException - If the thread is interrupted while waiting to acquire the lock

release

public void release()

Release the lock. No-op if the lock was never acquired.

toString

public String toString()

Overrides:

toString in class Object

getProc

LockProcedure getProc()