RWLockResource (Alluxio Core - Common Utilities 294 API)

java.lang.Object
- alluxio.resource.LockResource
- - alluxio.resource.RWLockResource

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable

Direct Known Subclasses:

RefCountLockResource
```
public class RWLockResource
extends LockResource
```
The RWLockResource is an extension of the LockResource which allows for downgrading of locks.

Field Summary
- Fields inherited from class alluxio.resource.LockResource
  mLock

Constructor Summary

Constructors
Constructor	Description
`RWLockResource(java.util.concurrent.locks.ReentrantReadWriteLock rwLock, LockMode mode, boolean acquireLock, boolean useTryLock)`	Creates a new instance of RW lock that will lock with the given mode.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type Method Description

boolean downgrade()
Downgrade from a write to a read lock.
- Methods inherited from class alluxio.resource.LockResource
  close, hasSameLock
- Methods inherited from class java.lang.Object
  clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - RWLockResource
```
public RWLockResource(java.util.concurrent.locks.ReentrantReadWriteLock rwLock,
                      LockMode mode,
                      boolean acquireLock,
                      boolean useTryLock)
```
    Creates a new instance of RW lock that will lock with the given mode.
    
    Parameters:
    
    rwLock - the read-write lock backing the resource
    
    mode - the initial lock mode if acquiring the lock
    
    acquireLock - whether or not to acquire the lock
    
    useTryLock - whether or not to use Lock.tryLock() when acquiring the resource
- Method Detail
  - downgrade
```
public boolean downgrade()
```
    Downgrade from a write to a read lock.
    
    Returns:
    
    if a successful downgrade was performed. Returns false if it was read locked