Package com.azure.core.util

Class FluxUtil

  • public final class FluxUtil
extends Object
    Utility type exposing methods to deal with Flux.

    • Method Detail

      • isFluxByteBuffer

        public static boolean isFluxByteBuffer​(Type entityType)
        Checks if a type is Flux<ByteBuffer>.
        Parameters:
        entityType - the type to check
        Returns:
        whether the type represents a Flux that emits ByteBuffer

      • collectBytesInByteBufferStream

        public static Mono<byte[]> collectBytesInByteBufferStream​(Flux<ByteBuffer> stream)
        Collects ByteBuffers emitted by a Flux into a byte array.
        Parameters:
        stream - A stream which emits ByteBuffer instances.
        Returns:
        A Mono which emits the concatenation of all the ByteBuffer instances given by the source Flux.
        Throws:
        IllegalStateException - If the combined size of the emitted ByteBuffers is greater than Integer.MAX_VALUE.

      • collectBytesInByteBufferStream

        public static Mono<byte[]> collectBytesInByteBufferStream​(Flux<ByteBuffer> stream,
                                                          int sizeHint)
        Collects ByteBuffers emitted by a Flux into a byte array.

        Unlike collectBytesInByteBufferStream(Flux), this method accepts a second parameter sizeHint. This size hint allows for optimizations when creating the initial buffer to reduce the number of times it needs to be resized while concatenating emitted ByteBuffers.

        Parameters:
        stream - A stream which emits ByteBuffer instances.
        sizeHint - A hint about the expected stream size.
        Returns:
        A Mono which emits the concatenation of all the ByteBuffer instances given by the source Flux.
        Throws:
        IllegalArgumentException - If sizeHint is equal to or less than 0.
        IllegalStateException - If the combined size of the emitted ByteBuffers is greater than Integer.MAX_VALUE.

      • byteBufferToArray

        public static byte[] byteBufferToArray​(ByteBuffer byteBuffer)
        Gets the content of the provided ByteBuffer as a byte array. This method will create a new byte array even if the ByteBuffer can have optionally backing array.
        Parameters:
        byteBuffer - the byte buffer
        Returns:
        the byte array

      • createRetriableDownloadFlux

        public static Flux<ByteBuffer> createRetriableDownloadFlux​(Supplier<Flux<ByteBuffer>> downloadSupplier,
                                                           BiFunction<Throwable,​Long,​Flux<ByteBuffer>> onDownloadErrorResume,
                                                           int maxRetries)
        Creates a Flux that is capable of resuming a download by applying retry logic when an error occurs.
        Parameters:
        downloadSupplier - Supplier of the initial download.
        onDownloadErrorResume - BiFunction of Throwable and Long which is used to resume downloading when an error occurs.
        maxRetries - The maximum number of times a download can be resumed when an error occurs.
        Returns:
        A Flux that downloads reliably.

      • createRetriableDownloadFlux

        public static Flux<ByteBuffer> createRetriableDownloadFlux​(Supplier<Flux<ByteBuffer>> downloadSupplier,
                                                           BiFunction<Throwable,​Long,​Flux<ByteBuffer>> onDownloadErrorResume,
                                                           int maxRetries,
                                                           long position)
        Creates a Flux that is capable of resuming a download by applying retry logic when an error occurs.
        Parameters:
        downloadSupplier - Supplier of the initial download.
        onDownloadErrorResume - BiFunction of Throwable and Long which is used to resume downloading when an error occurs.
        maxRetries - The maximum number of times a download can be resumed when an error occurs.
        position - The initial offset for the download.
        Returns:
        A Flux that downloads reliably.

      • withContext

        public static <T> Mono<T> withContext​(Function<Context,​Mono<T>> serviceCall)
        This method converts the incoming deferContextual from Reactor Context to Azure Context and calls the given lambda function with this context and returns a single entity of type T

        If the reactor context is empty, Context.NONE will be used to call the lambda function

        Code samples

         String prefix = "Hello, ";
 Mono<String> response = FluxUtil
     .withContext(context -> serviceCallReturnsSingle(prefix, context));
        Type Parameters:
        T - The type of response returned from the service call
        Parameters:
        serviceCall - The lambda function that makes the service call into which azure context will be passed
        Returns:
        The response from service call

      • withContext

        public static <T> Mono<T> withContext​(Function<Context,​Mono<T>> serviceCall,
                                      Map<String,​String> contextAttributes)
        This method converts the incoming deferContextual from Reactor Context to Azure Context, adds the specified context attributes and calls the given lambda function with this context and returns a single entity of type T

        If the reactor context is empty, Context.NONE will be used to call the lambda function

        Type Parameters:
        T - The type of response returned from the service call
        Parameters:
        serviceCall - serviceCall The lambda function that makes the service call into which azure context will be passed
        contextAttributes - The map of attributes sent by the calling method to be set on Context.
        Returns:
        The response from service call

      • toMono

        public static <T> Mono<T> toMono​(Response<T> response)
        Converts the incoming content to Mono.
        Type Parameters:
        T - The type of the Response, which will be returned in the Mono.
        Parameters:
        response - whose value is to be converted
        Returns:
        The converted Mono

      • fluxContext

        public static <T> Flux<T> fluxContext​(Function<Context,​Flux<T>> serviceCall)
        This method converts the incoming deferContextual from Reactor Context to Azure Context and calls the given lambda function with this context and returns a collection of type T

        If the reactor context is empty, Context.NONE will be used to call the lambda function

        Code samples

         String prefix = "Hello, ";
 Flux<String> response = FluxUtil
     .fluxContext(context -> serviceCallReturnsCollection(prefix, context));
        Type Parameters:
        T - The type of response returned from the service call
        Parameters:
        serviceCall - The lambda function that makes the service call into which the context will be passed
        Returns:
        The response from service call

      • toReactorContext

        public static Context toReactorContext​(Context context)
        Converts an Azure context to Reactor context. If the Azure context is null or empty, Context.empty() will be returned.
        Parameters:
        context - The Azure context.
        Returns:
        The Reactor context.

      • writeToOutputStream

        public static Mono<Void> writeToOutputStream​(Flux<ByteBuffer> content,
                                             OutputStream stream)
        Writes the ByteBuffers emitted by a Flux of ByteBuffer to an OutputStream.

        The stream is not closed by this call, closing of the stream is managed by the caller.

        The response Mono will emit an error if content or stream are null. Additionally, an error will be emitted if an exception occurs while writing the content to the stream.

        Parameters:
        content - The Flux of ByteBuffer content.
        stream - The OutputStream being written into.
        Returns:
        A Mono which emits a completion status once the Flux has been written to the OutputStream, or an error status if writing fails.

      • readFile

        public static Flux<ByteBuffer> readFile​(AsynchronousFileChannel fileChannel,
                                        int chunkSize,
                                        long offset,
                                        long length)
        Creates a Flux from an AsynchronousFileChannel which reads part of a file into chunks of the given size.
        Parameters:
        fileChannel - The file channel.
        chunkSize - the size of file chunks to read.
        offset - The offset in the file to begin reading.
        length - The number of bytes to read from the file.
        Returns:
        the Flux.

      • readFile

        public static Flux<ByteBuffer> readFile​(AsynchronousFileChannel fileChannel,
                                        long offset,
                                        long length)
        Creates a Flux from an AsynchronousFileChannel which reads part of a file.
        Parameters:
        fileChannel - The file channel.
        offset - The offset in the file to begin reading.
        length - The number of bytes to read from the file.
        Returns:
        the Flux.