Package nl.vpro.util.locker

Class ObjectLocker

java.lang.Object

nl.vpro.util.locker.ObjectLocker

public class ObjectLocker
extends Object

Author:

Michiel Meeuwissen

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	ObjectLocker.DefinesType
static interface	ObjectLocker.Listener
static class	ObjectLocker.LockHolder<K>	Most importantly this is a wrapper around ReentrantLock, but it stores some extra meta information, like the original key, thread, and initialization time.

Field Summary

Fields

Modifier and Type	Field	Description
static BiPredicate<StackTraceElement,AtomicInteger>	summaryBiPredicate

Method Summary

Modifier and Type	Method	Description
static List<ObjectLocker.LockHolder<? extends Serializable>>	currentLocks()
static Map<Serializable,ObjectLocker.LockHolder<? extends Serializable>>	getLockedObjects()
static void	listen(ObjectLocker.Listener listener)	You can register ObjectLocker.Listeners for lock events, for logging or other reporting purposes
static Predicate<StackTraceElement>	summaryPredicate()
static void	unListen(ObjectLocker.Listener listener)	The reverse of listen(Listener)
static <T> T	withKeyLock(Serializable id, @NonNull String reason, @NonNull Runnable runnable)
static <T> T	withKeyLock(Serializable id, @NonNull String reason, @NonNull Callable<T> callable)
static <T> T	withKeyLock(Serializable id, @NonNull String reason, @NonNull Consumer<ObjectLocker.LockHolder<Serializable>> consumer, @NonNull Callable<T> callable)
static <T, K extends Serializable> T	withObjectLock(@Nullable K key, @NonNull String reason, @NonNull Callable<T> callable, @NonNull Map<K,ObjectLocker.LockHolder<K>> locks, @NonNull BiPredicate<Serializable,K> comparable)
static <T, K extends Serializable> T	withObjectLock(@Nullable K key, @NonNull String reason, @NonNull Consumer<ObjectLocker.LockHolder<K>> consumer, @NonNull Callable<T> callable, @NonNull Map<K,ObjectLocker.LockHolder<K>> locks, @NonNull BiPredicate<Serializable,K> comparable)

Methods inherited from class java.lang.Object

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

Field Details

summaryBiPredicate

public static BiPredicate<StackTraceElement,AtomicInteger> summaryBiPredicate

Method Details

summaryPredicate

public static Predicate<StackTraceElement> summaryPredicate()

listen

public static void listen(ObjectLocker.Listener listener)

You can register ObjectLocker.Listeners for lock events, for logging or other reporting purposes

unListen

public static void unListen(ObjectLocker.Listener listener)

The reverse of listen(Listener)

getLockedObjects

public static Map<Serializable,ObjectLocker.LockHolder<? extends Serializable>> getLockedObjects()

withKeyLock

public static <T> T withKeyLock(Serializable id,
 @NonNull String reason,
 @NonNull Callable<T> callable)

withKeyLock

public static <T> T withKeyLock(Serializable id,
 @NonNull String reason,
 @NonNull Consumer<ObjectLocker.LockHolder<Serializable>> consumer,
 @NonNull Callable<T> callable)

withKeyLock

public static <T> T withKeyLock(Serializable id,
 @NonNull String reason,
 @NonNull Runnable runnable)

withObjectLock

public static <T,
K extends Serializable> T withObjectLock(@Nullable K key,
 @NonNull String reason,
 @NonNull Callable<T> callable,
 @NonNull Map<K,ObjectLocker.LockHolder<K>> locks,
 @NonNull BiPredicate<Serializable,K> comparable)

Parameters:

key - The key to lock on

reason - A description for the reason of locking, which can be used in logging or exceptions

locks - The map to hold the locks

comparable - this determines whether two given keys are 'comparable'. If they are comparable, but different, and occurring at the same time, than this means that some code is locking different things at the same time, which may be a cause of deadlocks. If they are difference but also not comparable, then this remains unknown. We may e.g. be locking on a certain crid and on a mid. They are different, but it is not sure that they are actually about two different objects.

withObjectLock

public static <T,
K extends Serializable> T withObjectLock(@Nullable K key,
 @NonNull String reason,
 @NonNull Consumer<ObjectLocker.LockHolder<K>> consumer,
 @NonNull Callable<T> callable,
 @NonNull Map<K,ObjectLocker.LockHolder<K>> locks,
 @NonNull BiPredicate<Serializable,K> comparable)

currentLocks

public static List<ObjectLocker.LockHolder<? extends Serializable>> currentLocks()

Since:

2.34