Package org.kiwiproject.concurrent

Class StripedLock

java.lang.Object

org.kiwiproject.concurrent.StripedLock

public class StripedLock
extends Object

StripedLock provides simple lambdas for encapsulating a block of code with a read/write lock.

The number of "stripes" indicates the maximum concurrent processes where the lock "key" is hashed and is used to select a lock. This is useful when you want tasks that operate in the same "context" to block one another without blocking unrelated tasks.

See Also:

Striped, ReadWriteLock

Implementation Note:

This StripedLock uses Guava's Striped under the covers. The ReadWriteLocks are re-entrant, and read locks can be held by multiple readers, while write locks are exclusive.

Constructor Summary

Constructors

Constructor	Description
StripedLock()	Creates a new StripedLock, using DEFAULT_KEY_WHEN_BLANK as the number of stripes.
StripedLock(int numStripes)	Creates a new StripedLock with the given number of stripes.
StripedLock(com.google.common.util.concurrent.Striped<ReadWriteLock> lock)	Create a new StripedLock using the given ReadWriteLock.

Method Summary

Modifier and Type	Method	Description
void	runWithReadLock(String lockKey, Runnable task)	Execute a Runnable task using the provided lock key and associated a READ lock.
void	runWithWriteLock(String lockKey, Runnable task)	Execute a Runnable task using the provided lock key and associated a WRITE lock.
<T> T	supplyWithReadLock(String lockKey, Supplier<T> task)	Execute a Supplier using the provided lock key and associated READ lock.
<T> T	supplyWithWriteLock(String lockKey, Supplier<T> task)	Execute a Supplier using the provided lock key and associated WRITE lock.

Methods inherited from class java.lang.Object

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

Constructor Detail

StripedLock

public StripedLock()

Creates a new StripedLock, using DEFAULT_KEY_WHEN_BLANK as the number of stripes.

StripedLock

public StripedLock(int numStripes)

Creates a new StripedLock with the given number of stripes.

Parameters:

numStripes - number of stripes

See Also:

Striped.readWriteLock(int)

StripedLock

public StripedLock(com.google.common.util.concurrent.Striped<ReadWriteLock> lock)

Create a new StripedLock using the given ReadWriteLock. This is useful if you have multiple interdependent usages that you want to share across the same set of locks.

Parameters:

lock - the striped lock to use

Method Detail

runWithReadLock

public void runWithReadLock(String lockKey,
                            Runnable task)

Execute a Runnable task using the provided lock key and associated a READ lock.

This implementation will block until the read lock is acquired.

Parameters:

lockKey - the lock key

task - the task to run

supplyWithReadLock

public <T> T supplyWithReadLock(String lockKey,
                                Supplier<T> task)

Execute a Supplier using the provided lock key and associated READ lock.

This implementation will block until the read lock is acquired.

Type Parameters:

T - the type of object being supplied

Parameters:

lockKey - the lock key

task - the task to supply a value

Returns:

the supplied value

runWithWriteLock

public void runWithWriteLock(String lockKey,
                             Runnable task)

Execute a Runnable task using the provided lock key and associated a WRITE lock.

This implementation will block until the write lock is acquired.

Parameters:

lockKey - the lock key

task - the task to run

supplyWithWriteLock

public <T> T supplyWithWriteLock(String lockKey,
                                 Supplier<T> task)

Execute a Supplier using the provided lock key and associated WRITE lock.

This implementation will block until the write lock is acquired.

Type Parameters:

T - the type of object being supplied

Parameters:

lockKey - the lock key

task - the task to supply a value

Returns:

the supplied value