org.apache.hadoop.hbase.procedure2.LockStatus Maven / Gradle / Ivy
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* to you under the Apache License, Version 2.0 (the
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*
* http://www.apache.org/licenses/LICENSE-2.0
*
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*/
package org.apache.hadoop.hbase.procedure2;
import org.apache.yetus.audience.InterfaceAudience;
/**
* Interface to get status of a Lock without getting access to acquire/release lock. Currently used
* in MasterProcedureScheduler where we want to give Queues access to lock's status for scheduling
* purposes, but not the ability to acquire/release it.
*/
@InterfaceAudience.Private
public interface LockStatus {
/**
* Return whether this lock has already been held,
*
* Notice that, holding the exclusive lock or shared lock are both considered as locked, i.e, this
* method usually equals to {@code hasExclusiveLock() || getSharedLockCount() > 0}.
*/
default boolean isLocked() {
return hasExclusiveLock() || getSharedLockCount() > 0;
}
/**
* Whether the exclusive lock has been held.
*/
boolean hasExclusiveLock();
/**
* Return true if the procedure itself holds the exclusive lock, or any ancestors of the give
* procedure hold the exclusive lock.
*/
boolean hasLockAccess(Procedure proc);
/**
* Get the procedure which holds the exclusive lock.
*/
Procedure getExclusiveLockOwnerProcedure();
/**
* Return the id of the procedure which holds the exclusive lock, if exists. Or a negative value
* which means no one holds the exclusive lock.
*
* Notice that, in HBase, we assume that the procedure id is positive, or at least non-negative.
*/
default long getExclusiveLockProcIdOwner() {
Procedure proc = getExclusiveLockOwnerProcedure();
return proc != null ? proc.getProcId() : -1L;
}
/**
* Get the number of procedures which hold the shared lock.
*/
int getSharedLockCount();
}