Class ScyllaPriorityQueue<T>.SynchronizedScyllaPriorityQueue

Thread-safe wrapper around ScyllaPriorityQueue<T> that synchronizes all operations using a single exclusive lock object.

Inheritance
object
ScyllaPriorityQueue<T>.SynchronizedScyllaPriorityQueue
Implements
Inherited Members
Namespace: Scylla.Core.Structures
Assembly: ScyllaCore.dll
Syntax
public sealed class ScyllaPriorityQueue<T>.SynchronizedScyllaPriorityQueue : IScyllaCollection<T>, IScyllaCollection
Remarks

All mutating and reading operations are serialized via lock(_lock). This guarantees that concurrent enqueue, dequeue, peek, and clear calls are safe, but it also means that high-contention scenarios may become a bottleneck. For very high throughput, consider using per-thread queues and merging results instead.

A few properties (IsFixedCapacity, Capabilities) are read from cached fields and do not acquire the lock. These values cannot change after construction.

Obtain an instance by calling AsSynchronized(object) or the builder's Synchronized(object) method rather than constructing this type directly.

Constructors

SynchronizedScyllaPriorityQueue(ScyllaPriorityQueue<T>, object)

Initializes a new instance of the synchronized wrapper around the specified priority queue.

Declaration
public SynchronizedScyllaPriorityQueue(ScyllaPriorityQueue<T> inner, object syncRoot)
Parameters
Type Name Description
ScyllaPriorityQueue<T> inner

The queue to wrap. Must not be null.
object syncRoot

The lock object to use for synchronization. If null, a new private lock is created.

Properties

Capabilities

Gets the capability flags supported by this priority queue instance. This value is cached at wrapper creation time and does not require synchronization.

Declaration
public ScyllaCollectionCapabilities Capabilities { get; }
Property Value
Type Description
ScyllaCollectionCapabilities

Capacity

Gets the current capacity of the backing buffer. This operation is thread-safe.

Declaration
public int Capacity { get; }
Property Value
Type Description
int

Count

Gets the number of elements currently in the priority queue. This operation is thread-safe.

Declaration
public int Count { get; }
Property Value
Type Description
int

IsEmpty

Gets a value indicating whether the priority queue is empty. This operation is thread-safe.

Declaration
public bool IsEmpty { get; }
Property Value
Type Description
bool

IsFixedCapacity

Gets whether the priority queue is fixed capacity. This value is cached at wrapper creation time and does not require synchronization.

Declaration
public bool IsFixedCapacity { get; }
Property Value
Type Description
bool

IsFull

Gets whether the priority queue is full. This is only meaningful when IsFixedCapacity is true. This operation is thread-safe.

Declaration
public bool IsFull { get; }
Property Value
Type Description
bool

SyncRoot

Gets the synchronization root object used for coordinating operations. All wrapper operations synchronize on this object.

Declaration
public object SyncRoot { get; }
Property Value
Type Description
object

ThreadSafety

Gets the thread-safety guarantees provided by this wrapper. Always returns Synchronized.

Declaration
public ScyllaCollectionThreadSafety ThreadSafety { get; }
Property Value
Type Description
ScyllaCollectionThreadSafety

Methods

Clear()

Removes all items from the priority queue, resetting it to an empty state. This operation is thread-safe.

Declaration
public void Clear()

Contains(T, IEqualityComparer<T>)

Determines whether the priority queue contains the specified item (O(n)). This operation is thread-safe.

Declaration
public bool Contains(T item, IEqualityComparer<T> comparer = null)
Parameters
Type Name Description
T item

Item to locate
IEqualityComparer<T> comparer

Optional equality comparer to use for comparison. If null, uses Default.
Returns
Type Description
bool

True if the item is found; otherwise false

CopyTo(Span<T>)

Copies up to destination.Length elements from the queue into the destination span in heap internal order (not priority-sorted order). This operation is thread-safe.

Declaration
public int CopyTo(Span<T> destination)
Parameters
Type Name Description
Span<T> destination

The span to copy elements into. Receives at most Count elements.
Returns
Type Description
int

The number of elements actually copied.

CopyTo(T[], int)

Copies up to destination.Length - destinationIndex elements from the queue into the destination array starting at destinationIndex, in heap internal order (not priority-sorted order). This operation is thread-safe.

Declaration
public int CopyTo(T[] destination, int destinationIndex)
Parameters
Type Name Description
T[] destination

The array to copy elements into. Must not be null.
int destinationIndex

The zero-based index in destination at which copying begins. Must be in the range [0, destination.Length].
Returns
Type Description
int

The number of elements actually copied.

EnsureCapacity(int)

Ensures the priority queue can hold at least the specified number of items without resizing. This operation is thread-safe.

Declaration
public void EnsureCapacity(int minCapacity)
Parameters
Type Name Description
int minCapacity

Minimum capacity to ensure
Exceptions
Type Condition
InvalidOperationException

Thrown if the wrapped queue is fixed-capacity

TryAdd(T)

Attempts to add an item to the priority queue. Equivalent to calling TryEnqueue(T). This operation is thread-safe.

Declaration
public bool TryAdd(T item)
Parameters
Type Name Description
T item

The item to add.
Returns
Type Description
bool

true if the item was successfully added; false if the queue is fixed-capacity and full.

TryDequeue(out T)

Attempts to dequeue the highest-priority item from the priority queue. This operation is thread-safe.

Declaration
public bool TryDequeue(out T item)
Parameters
Type Name Description
T item

When this method returns, contains the dequeued item if successful, otherwise default
Returns
Type Description
bool

True if an item was dequeued; false if empty

TryEnqueue(T)

Attempts to enqueue an item into the priority queue. This operation is thread-safe.

Declaration
public bool TryEnqueue(T item)
Parameters
Type Name Description
T item

Item to enqueue
Returns
Type Description
bool

True if enqueued; false if fixed-capacity and full

TryPeek(out T)

Attempts to peek at the highest-priority item without removing it. Equivalent to calling TryPeekTop(out T). This operation is thread-safe.

Declaration
public bool TryPeek(out T item)
Parameters
Type Name Description
T item

When this method returns true, contains the top-priority item. When this method returns false, contains default(T).
Returns
Type Description
bool

true if an item was available; false if the queue is empty.

TryPeekTop(out T)

Attempts to peek at the highest-priority item without removing it. This operation is thread-safe.

Declaration
public bool TryPeekTop(out T item)
Parameters
Type Name Description
T item

When this method returns, contains the top item if successful, otherwise default
Returns
Type Description
bool

True if an item was available; false if empty

TryRemove(out T)

Attempts to remove and return the highest-priority item from the queue. Equivalent to calling TryDequeue(out T). This operation is thread-safe.

Declaration
public bool TryRemove(out T item)
Parameters
Type Name Description
T item

When this method returns true, contains the dequeued highest-priority item. When this method returns false, contains default(T).
Returns
Type Description
bool

true if an item was dequeued; false if the queue is empty.

Implements

Extension Methods