Class RandomAccessCache<TKey, TValue, TWeight>

Represents concurrent cache optimized for random access. The number of items in the cache is limited by their weight.

Inheritance

object

Disposable

RandomAccessCache<TKey, TValue>

RandomAccessCache<TKey, TValue, TWeight>

Implements

IDisposable

IAsyncDisposable

IEnumerable<KeyValuePair<TKey, TValue>>

IEnumerable

Inherited Members

RandomAccessCache<TKey, TValue>.Eviction

RandomAccessCache<TKey, TValue>.KeyComparer

RandomAccessCache<TKey, TValue>.Capacity

RandomAccessCache<TKey, TValue>.ChangeAsync(TKey, CancellationToken)

RandomAccessCache<TKey, TValue>.Change(TKey, TimeSpan, CancellationToken)

RandomAccessCache<TKey, TValue>.ReplaceAsync(TKey, CancellationToken)

RandomAccessCache<TKey, TValue>.Replace(TKey, TimeSpan, CancellationToken)

RandomAccessCache<TKey, TValue>.TryRead(TKey, out RandomAccessCache<TKey, TValue>.ReadSession)

RandomAccessCache<TKey, TValue>.Contains(TKey)

RandomAccessCache<TKey, TValue>.TryRemoveAsync(TKey, CancellationToken)

RandomAccessCache<TKey, TValue>.TryRemove(TKey, out RandomAccessCache<TKey, TValue>.ReadSession, TimeSpan, CancellationToken)

RandomAccessCache<TKey, TValue>.InvalidateAsync(TKey, CancellationToken)

RandomAccessCache<TKey, TValue>.Invalidate(TKey, TimeSpan, CancellationToken)

RandomAccessCache<TKey, TValue>.InvalidateAsync(CancellationToken)

RandomAccessCache<TKey, TValue>.DisposeAsync()

RandomAccessCache<TKey, TValue>.DisposeAsyncCore()

RandomAccessCache<TKey, TValue>.Dispose(bool)

RandomAccessCache<TKey, TValue>.GetEnumerator()

Disposable.IsDisposed

Disposable.IsDisposing

Disposable.IsDisposingOrDisposed

Disposable.CreateException()

Disposable.DisposedTask

Disposable.GetDisposedTask<T>()

Disposable.TrySetDisposedException<T>(TaskCompletionSource<T>)

Disposable.TrySetDisposedException(TaskCompletionSource)

Disposable.Dispose(bool)

Disposable.DisposeAsyncCore()

Disposable.DisposeAsync()

Disposable.TryBeginDispose()

Disposable.Dispose()

Disposable.Dispose(IEnumerable<IDisposable>)

Disposable.DisposeAsync(IEnumerable<IAsyncDisposable>)

Disposable.Dispose<T>(ReadOnlySpan<T>)

Disposable.DisposeAsync(params IAsyncDisposable[])

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

object.ToString()

Namespace: DotNext.Runtime.Caching

Assembly: DotNext.Threading.dll

Syntax

public abstract class RandomAccessCache<TKey, TValue, TWeight> : RandomAccessCache<TKey, TValue>, IDisposable, IAsyncDisposable, IEnumerable<KeyValuePair<TKey, TValue>>, IEnumerable where TKey : notnull where TValue : notnull where TWeight : notnull

Type Parameters

Name	Description
TKey	The type of the keys.
TValue	The type of the values.
TWeight	The weight of the cache items.

Remarks

In contrast to RandomAccessCache<TKey, TValue>, the size of weight-based cache can grow to preserve collisionThreshold. When the number of collisions reaches the threshold, the cache resizes its internal structures and rehashes all the items. This process requires global lock of all items in the cache. Thus, throughput degrades. To minimize a chance of resize, you can specify initialCapacity large enough by the cost of memory footprint or increase collisionThreshold by the cost of the contention. However, TryRead(TKey, out ReadSession) never causes contention even if the cache is resizing.

Constructors

RandomAccessCache(int, TWeight, int)

Represents concurrent cache optimized for random access. The number of items in the cache is limited by their weight.

Declaration

protected RandomAccessCache(int initialCapacity, TWeight initialWeight, int collisionThreshold)

Parameters

Type	Name	Description
int	initialCapacity	The expected max number of items within the cache.
TWeight	initialWeight	The initial weight value.
int	collisionThreshold	The maximum number of allowed hash collisions. Small number increases the memory footprint, because the cache minimizes the contention for each key. Large number decreases the memory footprint by the increased chance of the lock contention. If MaxValue is specified, then the cache doesn't grow.

Remarks

In contrast to RandomAccessCache<TKey, TValue>, the size of weight-based cache can grow to preserve collisionThreshold. When the number of collisions reaches the threshold, the cache resizes its internal structures and rehashes all the items. This process requires global lock of all items in the cache. Thus, throughput degrades. To minimize a chance of resize, you can specify initialCapacity large enough by the cost of memory footprint or increase collisionThreshold by the cost of the contention. However, TryRead(TKey, out ReadSession) never causes contention even if the cache is resizing.

Methods

AddWeight(ref TWeight, TKey, TValue)

Adds a weight of the specified key/value pair to the total weight.

Declaration

protected abstract void AddWeight(ref TWeight total, TKey key, TValue value)

Parameters

Type	Name	Description
TWeight	total	The total weight of all items in the cache.
TKey	key	The key of the cache item.
TValue	value	The value of the cache item.

Remarks

This method can be called concurrently with RemoveWeight(ref TWeight, TKey, TValue).

IsEvictionRequired(ref readonly TWeight, TKey, TValue)

Checks whether the current cache has enough capacity to promote the specified key/value pair.

Declaration

protected abstract bool IsEvictionRequired(ref readonly TWeight total, TKey key, TValue value)

Parameters

Type	Name	Description
TWeight	total	The total weight of all items in the cache.
TKey	key	The key of the cache item.
TValue	value	The value of the cache item.

Returns

Type	Description
bool	true if the cache must evict one or more items to place a new one; otherwise, false.

RemoveWeight(ref TWeight, TKey, TValue)

Removes the weight of the specified cache item from the total weight.

Declaration

protected abstract void RemoveWeight(ref TWeight total, TKey key, TValue value)

Parameters

Type	Name	Description
TWeight	total	The total weight of all items in the cache.
TKey	key	The key of the cache item.
TValue	value	The value of the cache item.

Remarks

This method can be called concurrently with AddWeight(ref TWeight, TKey, TValue).

Implements

IDisposable

IAsyncDisposable

IEnumerable<T>

IEnumerable

Extension Methods

BasicExtensions.As<T>(T)

BasicExtensions.GetUserData<T>(T)

BasicExtensions.IsBetween<T, TLowerBound, TUpperBound>(T, TLowerBound, TUpperBound)

BasicExtensions.IsOneOf<T>(T, ReadOnlySpan<T>)

ExpressionBuilder.Const<T>(T)

AsyncLockAcquisition.AcquireLockAsync<T>(T, CancellationToken)

AsyncLockAcquisition.AcquireLockAsync<T>(T, TimeSpan, CancellationToken)

AsyncLockAcquisition.AcquireReadLockAsync<T>(T, CancellationToken)

AsyncLockAcquisition.AcquireReadLockAsync<T>(T, TimeSpan, CancellationToken)

AsyncLockAcquisition.AcquireWriteLockAsync<T>(T, bool, CancellationToken)

AsyncLockAcquisition.AcquireWriteLockAsync<T>(T, bool, TimeSpan, CancellationToken)

AsyncLockAcquisition.AcquireWriteLockAsync<T>(T, CancellationToken)

AsyncLockAcquisition.AcquireWriteLockAsync<T>(T, TimeSpan, CancellationToken)

LockAcquisition.AcquireReadLock<T>(T)

LockAcquisition.AcquireReadLock<T>(T, TimeSpan)

LockAcquisition.AcquireUpgradeableReadLock<T>(T)

LockAcquisition.AcquireUpgradeableReadLock<T>(T, TimeSpan)

LockAcquisition.AcquireWriteLock<T>(T)

LockAcquisition.AcquireWriteLock<T>(T, TimeSpan)

Collection.Append<T>(IEnumerable<T>, params T[])

Collection.Copy<T>(IEnumerable<T>, int, MemoryAllocator<T>?)

Collection.ElementAt<T>(IEnumerable<T>, int, out T)

Collection.FirstOrNone<T>(IEnumerable<T>)

Collection.ForEachAsync<T>(IEnumerable<T>, Func<T, CancellationToken, ValueTask>, CancellationToken)

Collection.ForEach<T>(IEnumerable<T>, Action<T>)

Collection.LastOrNone<T>(IEnumerable<T>)

Collection.Prepend<T>(IEnumerable<T>, params T[])

Collection.SequenceHashCode<T>(IEnumerable<T>, bool)

Collection.ToAsyncEnumerable<T>(IEnumerable<T>)

Collection.ToString<T>(IEnumerable<T>, string, string)

Enumerator.GetAsyncEnumerator<T>(IEnumerable<T>, CancellationToken)