Class AbstractCursor<T>

Namespace

DataStax.AstraDB.DataApi.Core.Enumeration

Assembly

DataStax.AstraDB.DataApi.dll

Abstract base class for cursors that iterate over query results in a streaming manner.

This cursor provides state management, buffering, and both synchronous and asynchronous enumeration capabilities. Results are fetched in batches from the underlying API and buffered for efficient iteration.

public abstract class AbstractCursor<T> : IDisposable, IEnumerable<T>, IEnumerable, IAsyncEnumerable<T>

Type Parameters

T

The type of the items or rows in the cursor.

Inheritance

object

AbstractCursor<T>

Implements

IDisposable

IEnumerable<T>

IEnumerable

IAsyncEnumerable<T>

Derived

PaginatedCursor<T, TResult, TOptions, TCursor>

Inherited Members

object.ToString()

object.Equals(object)

object.Equals(object, object)

object.ReferenceEquals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

Properties

Consumed

Gets the total number of items consumed from the cursor so far.

public int Consumed { get; protected set; }

Property Value

int

State

Gets the current state of the cursor.

public CursorState State { get; protected set; }

Property Value

CursorState

_buffer

Gets the internal buffer containing fetched results.

protected abstract List<T> _buffer { get; }

Property Value

List<T>

Methods

Buffered()

Returns the number of items currently buffered in memory.

public int Buffered()

Returns

int

The count of buffered items.

ConsumeBuffer(int)

Consumes and returns items from the buffer.

public IReadOnlyList<T> ConsumeBuffer(int max = 0)

Parameters

max int

The maximum number of items to consume. If 0 or omitted, consumes all buffered items.

Returns

IReadOnlyList<T>

A read-only list of consumed items.

Dispose()

Releases all resources used by the cursor and sets its state to Closed.

public virtual void Dispose()

FetchMoreAsync(CancellationToken, bool)

Fetches the next page of results from the underlying data source.

protected abstract Task<bool> FetchMoreAsync(CancellationToken cancellationToken, bool runSynchronously)

Parameters

cancellationToken CancellationToken

A cancellation token to cancel the operation.

runSynchronously bool

Whether to run the operation synchronously.

Returns

Task<bool>

True if more pages are available, false otherwise.

GetAsyncEnumerator(CancellationToken)

Returns an async enumerator to iterate over all items in the cursor.

public IAsyncEnumerator<T> GetAsyncEnumerator(CancellationToken cancellationToken = default)

Parameters

cancellationToken CancellationToken

An optional cancellation token to cancel the operation.

Returns

IAsyncEnumerator<T>

An async enumerator for the cursor.

Exceptions

CursorException

Thrown when attempting to iterate over a closed cursor.

GetEnumerator()

Returns an enumerator to iterate over all items in the cursor.

public IEnumerator<T> GetEnumerator()

Returns

IEnumerator<T>

An enumerator for the cursor.

Exceptions

CursorException

Thrown when attempting to iterate over a closed cursor.

HasNext()

Synchronously checks if there are more items available without consuming them.

public bool HasNext()

Returns

bool

True if there are more items available, false otherwise.

Remarks

The asynchronous version HasNextAsync(CancellationToken) is recommended to avoid potential deadlocks.

HasNextAsync(CancellationToken)

Asynchronously checks if there are more items available without consuming them.

public Task<bool> HasNextAsync(CancellationToken cancellationToken = default)

Parameters

cancellationToken CancellationToken

An optional cancellation token to cancel the operation.

Returns

Task<bool>

True if there are more items available, false otherwise.

MoveNext()

Synchronously moves to and returns the next item in the cursor.

public T MoveNext()

Returns

T

The next item, or null if there are no more items.

Remarks

The asynchronous version MoveNextAsync(CancellationToken) is recommended to avoid potential deadlocks.

MoveNextAsync(CancellationToken)

Asynchronously moves to and returns the next item in the cursor.

public Task<T> MoveNextAsync(CancellationToken cancellationToken = default)

Parameters

cancellationToken CancellationToken

An optional cancellation token to cancel the operation.

Returns

Task<T>

The next item, or null if there are no more items.

MoveNextAsync(CancellationToken, bool, bool)

Internal method to move to the next item, with options to peek or consume.

protected Task<T> MoveNextAsync(CancellationToken cancellationToken, bool peek, bool runSynchronously)

Parameters

cancellationToken CancellationToken

A cancellation token to cancel the operation.

peek bool

If true, returns the next item without consuming it.

runSynchronously bool

Whether to run the operation synchronously.

Returns

Task<T>

The next item, or null if there are no more items.

Rewind()

Resets the cursor to its initial state, allowing iteration to start over from the beginning.

public virtual void Rewind()

Remarks

This resets the consumed count and cursor state, but does not refetch data. The next iteration will start from the first page again.