Class JsonSingleStreamExtractor<TRecord>

Namespace: Wolfgang.Etl.Json

Assembly: Wolfgang.Etl.Json.dll

Extracts items of type TRecord from a single JSON array stream.

public sealed class JsonSingleStreamExtractor<TRecord> : ExtractorBase<TRecord, JsonReport>, IExtractWithProgressAndCancellationAsync<TRecord, JsonReport>, IExtractWithCancellationAsync<TRecord>, IExtractWithProgressAsync<TRecord, JsonReport>, IExtractAsync<TRecord> where TRecord : notnull

Type Parameters

TRecord: The type of items to extract. Must be notnull.

Inheritance: object

ExtractorBase<TRecord, JsonReport>

JsonSingleStreamExtractor<TRecord>

Implements: IExtractWithProgressAndCancellationAsync<TRecord, JsonReport>

IExtractWithCancellationAsync<TRecord>

IExtractWithProgressAsync<TRecord, JsonReport>

IExtractAsync<TRecord>

Inherited Members: ExtractorBase<TRecord, JsonReport>.ExtractAsync()

ExtractorBase<TRecord, JsonReport>.ExtractAsync(CancellationToken)

ExtractorBase<TRecord, JsonReport>.ExtractAsync(IProgress<JsonReport>)

ExtractorBase<TRecord, JsonReport>.ExtractAsync(IProgress<JsonReport>, CancellationToken)

ExtractorBase<TRecord, JsonReport>.ReportingInterval

ExtractorBase<TRecord, JsonReport>.CurrentItemCount

ExtractorBase<TRecord, JsonReport>.CurrentSkippedItemCount

ExtractorBase<TRecord, JsonReport>.MaximumItemCount

ExtractorBase<TRecord, JsonReport>.SkipItemCount

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.ReferenceEquals(object, object)

object.ToString()

Examples

using var stream = File.OpenRead("data.json");
var extractor = new JsonSingleStreamExtractor<Person>(stream);
await foreach (var person in extractor.ExtractAsync(cancellationToken))
{
    Console.WriteLine(person.Name);
}

Remarks

Reads a JSON array (e.g. [{"name":"Alice"},{"name":"Bob"}]) from a Stream and yields each deserialized object as an item in the async enumerable sequence. Uses DeserializeAsyncEnumerable<TValue>(Stream, JsonSerializerOptions, CancellationToken) for true streaming deserialization.

Constructors

JsonSingleStreamExtractor(Stream)

Initializes a new instance of the JsonSingleStreamExtractor<TRecord> class.

public JsonSingleStreamExtractor(Stream stream)

Parameters

stream Stream: The stream containing a JSON array to read from.

Exceptions

ArgumentNullException: Thrown when stream is null.

JsonSingleStreamExtractor(Stream, ILogger<JsonSingleStreamExtractor<TRecord>>)

Initializes a new instance of the JsonSingleStreamExtractor<TRecord> class with diagnostic logging.

public JsonSingleStreamExtractor(Stream stream, ILogger<JsonSingleStreamExtractor<TRecord>> logger)

Parameters

stream Stream: The stream containing a JSON array to read from.
logger ILogger<JsonSingleStreamExtractor<TRecord>>: The logger instance for diagnostic output.

Exceptions

ArgumentNullException: Thrown when stream or logger is null.

JsonSingleStreamExtractor(Stream, JsonSerializerOptions, ILogger<JsonSingleStreamExtractor<TRecord>>?)

Initializes a new instance of the JsonSingleStreamExtractor<TRecord> class with custom serialization options.

public JsonSingleStreamExtractor(Stream stream, JsonSerializerOptions options, ILogger<JsonSingleStreamExtractor<TRecord>>? logger = null)

Parameters

stream Stream: The stream containing a JSON array to read from.
options JsonSerializerOptions: The JSON serializer options to use for deserialization.
logger ILogger<JsonSingleStreamExtractor<TRecord>>: An optional logger instance for diagnostic output.

Exceptions

ArgumentNullException: Thrown when stream or options is null.

JsonSingleStreamExtractor(Stream, JsonTypeInfo<TRecord>, ILogger<JsonSingleStreamExtractor<TRecord>>?)

Initializes a new instance of the JsonSingleStreamExtractor<TRecord> class with source-generated type metadata for AOT-friendly, reflection-free deserialization.

public JsonSingleStreamExtractor(Stream stream, JsonTypeInfo<TRecord> typeInfo, ILogger<JsonSingleStreamExtractor<TRecord>>? logger = null)

Parameters

stream Stream: The stream containing a JSON array to read from.
typeInfo JsonTypeInfo<TRecord>: The source-generated type metadata for TRecord.
logger ILogger<JsonSingleStreamExtractor<TRecord>>: An optional logger instance for diagnostic output.

Exceptions

ArgumentNullException: Thrown when stream or typeInfo is null.

Methods

CreateProgressReport()

Creates a progress report of type TProgress. This gives the derived class the opportunity to implement a custom progress report that is specific to the extraction process.

protected override JsonReport CreateProgressReport()

Returns

JsonReport: Progress of type TProgress

CreateProgressTimer(IProgress<JsonReport>)

Creates the Wolfgang.Etl.Abstractions.IProgressTimer used to drive progress callbacks. Override this method in a derived class to inject a custom timer (for example, a custom implementation that allows manual control in unit tests).

protected override IProgressTimer CreateProgressTimer(IProgress<JsonReport> progress)

Parameters

progress IProgress<JsonReport>: The progress sink that will receive callbacks.

Returns

IProgressTimer: A started Wolfgang.Etl.Abstractions.IProgressTimer instance.

ExtractWorkerAsync(CancellationToken)

This method is the core implementation of the extraction logic and should be overridden by derived classes.

protected override IAsyncEnumerable<TRecord> ExtractWorkerAsync(CancellationToken token)

Parameters

token CancellationToken: A CancellationToken to observe while waiting for the task to complete.

Returns

IAsyncEnumerable<TRecord>: IAsyncEnumerable<TSource> The result may be an empty sequence if no data is available or if the extraction fails.