org.apache.hc.core5.http.impl.nio

## Class IdentityDecoder

- java.lang.Object
- - org.apache.hc.core5.http.impl.nio.AbstractContentDecoder
  - - org.apache.hc.core5.http.impl.nio.IdentityDecoder

- All Implemented Interfaces:
    ContentDecoder, FileContentDecoder

      public class IdentityDecoder
      extends AbstractContentDecoder
      implements FileContentDecoder

  Content decoder that reads data without any transformation. The end of the content entity is delineated by closing the underlying connection (EOF condition). Entities transferred using this input stream can be of unlimited length.

  This decoder is optimized to transfer data directly from the underlying I/O session's channel to a `FileChannel`, whenever possible avoiding intermediate buffering in the session buffer.

  Since:
    4.0

- - ### Field Summary

    - ### Fields inherited from class org.apache.hc.core5.http.impl.nio.AbstractContentDecoder

      `completed`

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `IdentityDecoder(ReadableByteChannel channel, SessionInputBuffer buffer, BasicHttpTransportMetrics metrics)`

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `int` | `read(ByteBuffer dst)` Reads a portion of content from the underlying channel
    `String` | `toString()`
    `long` | `transfer(FileChannel dst, long position, long count)` Transfers a portion of entity content from the underlying network channel into the given file channel.

    - ### Methods inherited from class org.apache.hc.core5.http.impl.nio.AbstractContentDecoder

      `buffer, channel, fillBufferFromChannel, getTrailers, isCompleted, metrics, readFromChannel, readFromChannel, setCompleted, setCompleted`

    - ### Methods inherited from class java.lang.Object

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait`

    - ### Methods inherited from interface org.apache.hc.core5.http.nio.ContentDecoder

      `getTrailers, isCompleted`

- - ### Constructor Detail

    - #### IdentityDecoder

          public IdentityDecoder(ReadableByteChannel channel,
                                 SessionInputBuffer buffer,
                                 BasicHttpTransportMetrics metrics)

  - ### Method Detail

    - #### read

          public int read(ByteBuffer dst)
                   throws IOException

      Description copied from interface: `ContentDecoder`
      Reads a portion of content from the underlying channel
      Specified by:
        `read` in interface `ContentDecoder`
      Parameters:
        `dst` - The buffer into which entity content is to be transferred
      Returns:
        The number of bytes read, possibly zero, or -1 if the channel has reached end-of-stream
      Throws:
        `IOException` - if I/O error occurs while reading content

    - #### transfer

          public long transfer(FileChannel dst,
                               long position,
                               long count)
                        throws IOException

      Description copied from interface: `FileContentDecoder`
      Transfers a portion of entity content from the underlying network channel into the given file channel.

      Warning: Many implementations cannot write beyond the length of the file. If the position exceeds the channel's size, some implementations may throw an IOException.

      Specified by:
        `transfer` in interface `FileContentDecoder`
      Parameters:
        `dst` - the target FileChannel to transfer data into.
        `position` - The position within the file at which the transfer is to begin; must be non-negative. Must be less than or equal to the size of the file
        `count` - The maximum number of bytes to be transferred; must be non-negative
      Returns:
        The number of bytes, possibly zero, that were actually transferred
      Throws:
        `IOException` - if some I/O error occurs.

    - #### toString

          public String toString()

      Overrides:
        `toString` in class `Object`

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